CRIME ANALYSIS FOR PROBLEM SOLVERS

In 60 Small Steps

Ronald V. Clarke & John E. Eck

U.S. Department of Justice

Office of Community Oriented Policing Services

COMMUNITY ORIENTED POLICING SERVICES

COPS U.S. DEPARTMENT OF JUSTICE

Center for Problem-Oriented Policing
This project was supported by cooperative agreement #2003CKWXK048 by the Office of Community Oriented

Policing Services, U.S. Department of Justice. The opinions contained herein are those of the authors and do not

necessarily represent the official position of the U.S. Department of Justice. References to specific companies,

products, or services should not be considered an endorsement of the product by the author or the U.S. Department

of Justice. Rather, the references are illustrations to supplement discussion of the issues.
Crime Analysis for Problem Solvers

In 60 Small Steps

Ronald V. Clarke

John E. Eck

Guardian

Handler

Manager

Offender

CRIME

Place

Target/Victim

Crime Analysis for Problem Solvers in 60 Small Steps

his is a revised and extended version of a manual, Become a ProblemSolving Crime Analyst, that we wrote for the Jill Dando Institute of Crime

Science at University College London, with financial support from the

Home Office. We are most grateful to the Institute and to the Home Office

for allowing us to produce this version for the United States. We are also

grateful to the Office of Community Oriented Policing Services for

commissioning the work. In the Acknowledgements page of the earlier

version we thanked many colleagues and friends on whose work we had

freely drawn. Those who have materially assisted us in completing this

version by supplying material for inclusion, commenting on drafts, or in

other ways, include: Stacy Belledin, Rachel Boba, Karen Bullock, Barbie

Brookover, Christopher Bruce, Andy Brumwell, Graham Farrell, Rob

Guerette, Samantha Gwinn, Shane Johnson, Johannes Knutsson, Gloria

Laycock, Nancy Leach, Deborah Loewen, Tamara Madensen, Mangai

Natarajan, Cynthia Pappas, Ken Pease, Nanci Plouffe, Barry Poyner, Jerry

Ratcliffe, George Rengert, Nick Ross, Kim Rossmo, Rana Sampson,

Matthew Scheider, Karin Schmerler, Michael Scott, Nick Tilley, Susan

Wernicke, Matt White, and Deborah Lamm Weisel. We thank all of them.

ACKNOWLEDGEMENTS

T

Crime Analysis for Problem Solvers in 60 Small Steps

AUTHORS

Ronald Clarke is university professor in the school of Criminal Justice at Rutgers,

The State University of New Jersey, and visiting professor at the Jill Dando

Institute of Crime Science, University College London. He worked for many years

in the Home Office Research and Planning Unit, where he contributed to the

development of situational crime prevention and the British Crime Survey. He is

associate director of the Center for Problem-Oriented Policing and chair of the

judges for the annual Herman Goldstein Award for Excellence in ProblemOriented Policing. He can be reached at: rclarke@andromeda.rutgers.edu.

RONALD V. CLARKE

John Eck is professor of criminal justice at the University of Cincinnati. He has

contributed to the development of problem-oriented policing since 1984 when he

studied the first full-scale attempt to implement the concept in the United States

at Newport News, Virginia. He helped to develop a number of now standard

techniques in problem-oriented policing, including the SARA model and the

problem analysis triangle. Dr. Eck is an affiliate member of the Center for

Problem-Oriented Policing. He is a judge for the Tilley Award for Excellence in

Problem-Oriented Policing. Dr. Eck was a member of the Committee to Review

Research on Police Policy and Practice (2000-2003) of the National Academy of

Sciences. He can be reached at: john.eck@uc.edu.

JOHN E. ECK
One of the primary concerns in policing in the United

States today – and for the foreseeable future – is

the severe constraint on spending. The lion's share

of police budgets is consumed in personnel costs. As a

result, many police agencies are already operating

significantly below their authorized strength. Funds to hire

new officers to meet growing needs are hard to obtain.

And, of special relevance here, traditional forms of policing,

because they are so heavily dependent on personnel, are

being curtailed. Calls cannot be handled as completely and

quickly as in the past. Personnel cannot be as freely

assigned to increasing the police presence on the streets in

labor-intensive tactics, such as crackdowns, sweeps, and

special task forces.

This reality is a powerful new force for rethinking the way

in which we police. It connects with prior efforts to

promote greater concern for the effectiveness of the police.

And it lends fresh impetus to meeting a long-standing,

neglected need – the need to equip the police with an

institutionalized capacity to examine its work product; to

routinely ask, before committing to more of the same, what

it is that the police are expected to accomplish and how

they can more effectively accomplish it.

Rethinking current methods requires a new understanding

of the role of the police – both on the part of the police

and the public they serve. It is essential to recognize that

the police function is not as simple as it is sometimes

portrayed. It is incredibly complex. It is not a singular

function, commonly defined as enforcing the law. It

requires dealing with a broad range of behavioral

problems, each quite different from the other. It does not

consist simply of reacting to an endless array of incidents.

Police are now expected to prevent them from occurring in

the first instance.

A fresh perspective on policing requires that the police

examine, in depth, each of the numerous behavioral

problems that together constitute their business; that they

consider a broader range of strategies on how best to

prevent, reduce, or eliminate each of them; and that they

weigh more precisely their effectiveness upon adopting a

new targeted response. This is the essence of problemoriented policing.

Many advances have been realized under the umbrella of

problem-oriented policing since the concept was first

introduced in 1979. But these have not been

mainstreamed within policing. Their implementation has

been spotty, uneven, and without deep and lasting roots.

They remain overshadowed by the dominant, continuing

commitment to traditional policing and its heavy

dependence on lots of police officers patrolling and 

making arrests.

Greater concern about police effectiveness in dealing with

specific behavioral problems need not start from scratch.

Collectively, we know much about the wide range of

behavioral problems that constitute police business and

how best to prevent them. This knowledge can be found in

the substantial literature on crime and crime prevention –

especially in the literature on situational crime prevention.

Much of value can be found, too, among the practices of

police agencies and in the minds of experienced police

officers, but this experience and expertise must be tapped

and subjected to rigorous analysis.

The Center for Problem-Oriented Policing (POP Center)

(www.popcenter.org) now serves as a locus for the

collection of the growing body of knowledge regarding

problems commonly encountered by the police. It

disseminates this material in various ways, but primarily

through the publication of its problem-oriented guides.

Each guide synthesizes existing knowledge and evaluated

practices regarding a specific problem, and stimulates

police to advance their own thinking about how best to

handle the problem in its local context.

While the POP Center has documented hundreds of

successful cases in problem-oriented policing, a major

impediment to advancing the concept has been the

absence of an analytical capacity within police agencies.

Many police agencies do employ one or more crime

analysts, but some of the largest and more advanced police

organizations do not. When employed, the job of the crime

analyst is often narrowly limited to tabulating crimes that

occur. In others, it extends to identifying patterns of crimes

with the primary objective of identifying the likely offender

so that he/she can be apprehended. In its more ambitious

form, the crime analyst's job may include identifying factors

contributing to a crime pattern, but the job of deciding

how to respond to these factors is usually deferred to

operational personnel, who then tend to use traditional

means for dealing with them.

foreword foreword
Crime Analysis for Problem Solvers in 60 Small Steps

Meanwhile, the field of crime analysis itself has grown

much more sophisticated. A strong literature on its

potential is now available. The ability to electronically

capture, store, and retrieve massive amounts of data that

police routinely collect is infinitely greater than it was just

a decade ago. The capacity to map crime geographically is

stunning, and is now a major, indispensable tool in crime

analysis. Standard approaches have been developed for

the collection, analysis, and dissemination of intelligence

across jurisdictional lines.

In this manual, Ronald Clarke and John Eck set out a

much more ambitious and potentially productive agenda

for the analyst. They outline a role in which the crime

analyst invests heavily in seeking new responses to the

problems that are diagnosed and participates directly in

efforts to test and implement them. The analyst is

expected to contribute to exploring new, more creative,

and potentially more effective ways of carrying out the

police job. Through this manual, Clarke and Eck

demonstrate how one analyst, properly trained and

utilized, has the potential to increase many times the

productivity and effectiveness of perhaps hundreds of

police officers. Understood in this way, an investment in

crime analysts can be a smart way to increase the return

on the substantial investment that communities make in

sworn police personnel.

Blending their expertise as researchers and their

familiarity with policing, Clarke and Eck have collected all

of the knowledge and methodology that is relevant and

currently available; organized it in 60 small segments or

steps that build logically upon each other; and

communicated the material in a style that is both concise

and engaging. The volume is packed with vital and

sophisticated information that makes it one of the most

significant publications addressed to the policing field in

the past several decades.

The most immediate goal of the manual is to help the

relatively small number of individuals now commonly

employed in police agencies as crime analysts to expand

their function and thereby contribute more to the

effectiveness of their agency's operations. It is intended,

more ambitiously, to contribute to the training of new

crime analysts or problem-solvers, to increasing their

number, and to their development as a distinct and vital

profession. But problem analysis is not the exclusive

domain of technicians. We hope that, everyone else in a

police agency, from officers on the beat to police

executives, and, more broadly, those in both the public

and private sector concerned about crime, will incorporate

the line of thinking set forth in the manual into the

perspectives they bring to their work.

Herman Goldstein

Professor of Law Emeritus

University of Wisconsin-Madison

FOREWORD
T

his 60-step manual assumes that you are an

experienced analyst and that you are accustomed to

providing the kind of information needed to support

police operations. This means that:

1. You use modern computing and know how to access

and manipulate comprehensive databases.

2. You know how to use software to map crime, to

identify hot spots, and to relate these to demographic

and other data.

3. You routinely produce charts showing weekly or

monthly changes in crime at departmental and beat

level, perhaps to support CompStat-style operations.

4. You are accustomed to carrying out analyses into such

topics as the relationship between the addresses of

known offenders and local outbreaks of car theft and

burglary.

5. You may have carried out some before-and-after

evaluations of crackdowns, such as on residential

burglaries or car thefts.

6. You have some basic knowledge of statistics and

research methodology such as is provided by an

undergraduate social science degree.

The manual builds on this experience to prepare you for a

different analytic role as a key member of a problemsolving team. Indeed, the latest writings on problemoriented policing see crime analysts as central to this new

way of policing communities. These writers argue that

many of the weaknesses of current practice result from

the insufficient involvement of well-trained crime analysts

at each stage of the problem-solving process.

The manual prepares you for this new role by providing

you with a basic knowledge of problem-oriented policing

and the related fields of environmental criminology and

situational crime prevention. You cannot adequately

function as a problem-solving crime analyst without being

conversant with these fields. Nor can you fill this role

without rethinking your job, and the early sections of the

manual explain how to take a more proactive approach.

You cannot simply wait for your police colleagues to come

to you with requests for information. Instead, you must

take the initiative at every stage of the project in defining

the scope of the problem-solving effort, in trying to

analyze the causes of the problem, in helping to find an

effective response, and in setting up the project so that it

can be evaluated and the police can learn from the

results. This means that you must be an integral member

of the problem-solving team, that you must explore

sources of information and data well beyond those that

you normally use in your work, that you must stick with a

particular project much longer than you normally would

and, finally, that you will share the credit for its success, or

the disappointment for its failure, equally with the other

members of the team.

The manual assumes that analysts who take on this new

role are interested in contributing to the development of

their profession. Assisted by vastly improved data-bases

and powerful computing hardware and software, crime

analysis is on the verge of becoming an exciting new

specialty. Indeed, it has already begun to attract a cadre

of well-trained and highly motivated professionals who

are vital to the development of policing in the 21st

century. You can make your contribution by

communicating the results of your work in professional

meetings and in the journals of your profession. By doing

so, you will not only help your profession and policing in

general, but you will become a more informed and

valuable resource to your own force.

The manual is short enough to get through in a weekend.

It would be hard work and probably worth doing, but it

was not designed to be read and then shelved. Instead,

we hope that you will find it to be an indispensable

reference source that you will keep near your desk,

consulting it whenever needed in the course of a

problem-solving project. This is why it is designed to be

robust, allowing for continuous use. When open at a

particular step it is designed to lie flat on your desk so

that you can consult it easily when working at 

your computer.

We have arranged the steps to follow logically one from

another, in line with the SARA model (Scanning, Analysis,

Response and Assessment), though each is self-contained

and deals with a specific topic. This should make it

unnecessary for you to leaf through the manual, jumping

from place to place, when dealing with a particular topic.

To get the best out of the manual you should be

thoroughly familiar with the list of contents and you

should have browsed through sections that interest you to

get an idea of the coverage. But you need only study a

particular step when you have an immediate need for the

information it contains. In any case, this is the best way to

learn: to seek and apply information when you have a

practical need for it.

read this first read this first
Crime Analysis for Problem Solvers in 60 Small Steps

In some cases, we do deal with a particular topic in more

than one place. For example, Step 12 provides a general

introduction to the concept of displacement, while Steps

48 and 49 explain how to check for various forms of

displacement at the evaluation stages. The combined

glossary and index at the end of the manual should help

you find where a topic is mentioned in more than

one place.

We use examples from other countries as well as from the

United States. We sought the best examples to make our

point, so even if the context is foreign, the principles are

universal. We hope this diversity of ideas stimulates

creative thought: "Could that approach be adapted to

this problem? How could we do it?"

We have not referenced the manual as fully as an

academic publication for several reasons. We have already

tried to distill the essentials of the literature at each step.

We also doubt that busy crime analysts will have much

time for academic reading. Lastly, few of you will have

ready access to the specialized libraries that hold this

material. But occasionally you will need to know more

about a topic, and at each step we identify key articles or

books that you should be able to obtain more easily.

Where possible, we have chosen those that are accessible

on the Web. If you need help with references, feel free to

email one of us at the addresses given earlier. We would

also be glad to receive any comments on the manual,

especially suggestions for improvement, which could be

useful if we prepare later editions. Most important, please

don't be shy about suggesting your own analyses 

for inclusion!

READ THIS FIRST

As explained in the Acknowledgements, we have developed this manual from an earlier version that we

prepared for the Jill Dando Institute of Crime Science at University College London. We have removed

British terms and spelling and have replaced many of the British examples with American ones. But you

will still find many references to things British. In particular you will see frequent mention of the Home

Office, which is equivalent to the U.S. Department of Justice. It has overall responsibility for matters

relating to crime and justice in England and Wales, including the police. There are only 43 police forces in

England and Wales (for a population of about 50 million), so the forces are much larger than most

American police departments. There is also much more uniformity among British police forces in policies,

rank structures, equipment, and deployment. This is partly due to the oversight provided by the Home

Office (which provides 51 percent of each force's budget) and regular inspections by Her Majesty's

Inspectors of Constabulary. The Home Office also funds a great deal of research on crime and criminal

justice and has its own large research department that publishes many studies of direct, practical

relevance to police. Recently, it has sponsored much work on problem-oriented policing, including the

original version of this manual.

The Home Office and the British Police
Crime Analysis for Problem Solvers in60 small steps

Acknowledgements

Authors

Foreword

Read This First

Prepare Yourself

1. Rethink your job

2. Be the local crime expert 

3. Know what is effective (and not) in policing

Learn About Problem-Oriented Policing

4. Become a POP expert

5. Be true to POP

6. Be very crime specific

7. Be guided by SARA - not led astray!

Study Environmental Criminology

8. Use the problem analysis triangle

9. Know that opportunity makes the thief 

10. Put yourself in the offender's shoes

11. Expect offenders to react

12. Don't be discouraged by the displacement doomsters 

13. Expect diffusion of benefits

Scan for Crime Problems

14. Use the CHEERS test when defining problems

15. Know what kind of problem you have

16. Study the journey to crime

17. Know how hot spots develop 

18. Learn if the 80-20 rule applies

Analyze in Depth

19. Research your problem

20. Formulate hypotheses 

21. Collect your own data

22. Examine your data distributions

23. Diagnose your hot spot 

24. Know when to use high-definition maps

25. Pay attention to daily and weekly rhythms 

26. Take account of long-term change

TABLE OF CONTENTS
27. Know how to use rates and denominators 

28. Identify risky facilities

29. Be ready for repeat victimization

30. Consider repeat offending

31. Know the products that are CRAVED by thieves

32. Conduct case control studies

33. Measure association 

34. Look for crime facilitators 

35. Understand the crime from beginning to end

36. Be sure to answer the five "W" (and one "H") questions

37. Recognize that to err is human

Find a Practical Response

38. Embrace your key role at response

39. Increase the effort of crime

40. Increase the risks of crime

41. Reduce the rewards of crime

42. Reduce provocations

43. Remove excuses for crime

44. Find the owner of the problem 

45. Choose responses likely to be implemented

Assess the Impact

46. Conduct a process evaluation

47. Know how to use controls

48. Consider geographical and temporal displacement

49. Examine displacement to other targets, tactics and crime types

50. Watch for other offenders moving in

51. Be alert to unexpected benefits

52. Expect premature falls in crime

53. Test for significance

Comunicate Effectively

54. Tell a clear story

55. Make clear maps

56. Use simple tables

57. Use simple figures

58. Organize powerful presentations

59. Become an effective presenter

60. Contribute to the store of knowledge

Glossary/Index

TABLE OF CONTENTS
1

L

ike most crime analysts, you probably think of your

job in rather modest terms. You do not solve crimes

single-handed. Nor do you take the lead in setting

departmental crime-fighting priorities. Instead, you crunch

data for those who do the "real" work of finding better

ways to arrest criminals. You respond to requests for the

latest statistics on burglary or car theft from beat officers

and sergeants. You map crime for weekly meetings so that

the lieutenant knows where to demand more effort. And

you compile monthly statistics that others need for their

reports. In other words, you sit in the back seat while

others do the driving, asking for your help only when they

need it.

This manual will help you rethink your role. Even someone

sitting in the back seat can help the lost driver find

direction. Control over information is crucial, and the

ability to analyze it is all-important. The person who

learns how to do so becomes an essential member of the

team. But we are not talking here about power or status.

We are referring instead to a challenge facing all police

forces: how to solve enduring and repetitive crime

problems. Think of yourself as a member of a team

helping to solve these problems, with a particular role in

that team. As you use this manual you will begin to see

how to perform that role and you will also see how

essential it is.

To play that essential role, you need to know more. We

are not referring to improved computer skills or mapping

ability, important though these are. You need to learn

more about crime itself, to become a resource to your

department as an expert on crime in your local area. If

there is a new burglary wave, you should be the first to

know and the first to tell. Analyze and map the statistics

and get the basic facts yourself. If you wait, others will say

what is happening without any factual basis. Once more

you will be relegated to the back seat. You are the "facts"

person and you must find things out as soon as possible,

using the best means possible. This will often mean going

beyond police data, and this manual will tell you how to

use other data sources, including interviews with victims

and offenders and records of crime kept by businesses.

Becoming a source of information is a first step. The ideal

is to also be a source of advice. Whether you can do this

depends on your supervisor's openness, but at least you

can provide options or support the suggestions of others

with information and data.

In particular you should know what works in policing and

what does not. How effective is random patrol? How

often do police come upon a crime in progress? How

often are crimes solved later through patient detective

work or forensic evidence? How productive are stakeouts

and surveillance in terms of arrests? How much do

crackdowns cost in officers' time? What are the arrest

rates for different kinds of crimes? How many crimes of

different kinds are even reported to the police? Knowing

answers to these questions will tell you why even the

most hard-working officers are relatively ineffective in

preventing crime, and why an increasing number of police

forces are now turning to problem-oriented policing.

The main purpose of this manual is to tell you about

problem-oriented policing and the vital part you can play

in its implementation. The manual helps you distinguish

problem-oriented policing from other forms of community

policing. It shows you how problem-oriented policing can

become more effective by using environmental

criminology and situational crime prevention. It describes

each of the four stages of a problem-oriented project -

scanning for crime problems, analyzing a specific problem

in depth, responding to the problem by implementing

solutions and assessing the results of the project - and

gives examples of the data and information that you

could provide at each stage. Finally, it illustrates the kind

of analyses that you can undertake at all four stages to

work effectively as a member of the 

problem-solving team.

These stages of a problem-oriented project will require

that you remain working on a single project much longer

than your traditional analytic role requires. You can expect

to stay with a problem-solving project for weeks or

months, rather than just the few hours needed to plot a

burglary hot spot or provide a monthly report. Where a

detailed assessment of results is needed, your involvement

might even stretch for more than a year. You may have to

explain this to officers who come to you for help. At first

they may be surprised that you expect to stick so long

with a project, but soon they will appreciate your

commitment to making the effort worthwhile.

Your time has been wasted if you cannot communicate

the results of your work. Later sections of the manual give

suggestions for communicating more effectively by telling

a story using simple maps and tables. Your presentations

should try to lead to a course of action, but you must

always explain the limits of your data and tell officers

where your recommendations are based on best guesses

rather than facts.

1. Rethink your job
Crime Analysis for Problem Solvers in 60 Small Steps

PREPARE YOURSELF

This manual cannot tell you everything you must know or

do to become a problem-solving analyst. You must seek

constantly to enhance your professional and technical

skills and keep up-to-date with the latest developments in

relevant fields. You must take the initiative in finding more

effective ways to capture information and more efficient

ways to process it, as time freed up from routine tasks

means more time for the new work of problem analysis.

You must read more widely and explore other sources of

information. Additional readings are recommended

throughout this manual, but you will also have to find

material for yourself. A good way to do this is through

networking with analysts in other departments and by

attending professional meetings of analysts, police and

criminologists. And try to pass on lessons you have

learned by making presentations at these meetings of

valuable or novel analyses you have undertaken.

In short, you should begin to see yourself as more than

just a technician, skilled in manipulating and presenting

data. You should become more like a researcher - albeit

with a highly practical focus - one who is bringing the

very best that science can offer to make policing more

effective. By the same token, also recognize that you are

part of an emerging profession, which you can help 

to develop.

Rethink your job:

• Become a crime expert 

• Know what works in policing 

• Promote problem solving 

• Take your place on the project team 

• Learn about environmental criminology 

• Hone your research skills 

• Communicate effectively

• Enhance your profession 

Read More:

Braga, Anthony (2002). Problem-Oriented Policing and

Crime Prevention, Monsey, NY: Criminal Justice Press.
2

H

ow often have you been asked the following sorts

of questions in your work?

• What locations are hot for auto theft right now?

• Which convenience stores are repeatedly robbed 

and why? 

• What are burglars taking from shops and where do they

fence the goods?

• Is there less crime in the better-lit streets? 

• Which apartment complexes harbor drug markets? 

Some of these you might not have been able to answer at

all - others only after a special analysis. But suppose you

had the answers to them and many more at your

fingertips? Suppose you were the expert on crime in your

force area? In fact, nobody else can fill that role:

• Individual officers are too busy answering calls.

• Detectives are focused on specific cases.

• Sergeants are supervising their officers.

• Lieutenants are overseeing patrol responses for large

geographic areas.

• The chief, his or her assistants and captains are busy

with administrative issues.

In short, nobody can see the whole crime picture. But if

you became the local crime expert it would help make

your department more informed, efficient, and capable of

using its resources to reduce crime. It would provide more

opportunity to warn citizens, to detect offenders, and to

initiate prevention efforts. In short, you could help a lot of

people by gathering the right information.

To become the local crime expert, sit in regularly with

dispatchers and talk to officers about what they are

seeing. Remember the late shift might not see officers on

the early shift, and those on one side of town might not

see officers on the other. They often talk about exceptions,

not the rules, about what made them angry, not about the

routine. Yet the routine is the bread and butter of 

crime analysis.

Take ride-alongs as often as time permits. Not only will

you get to know more of the officers in your department,

but you will also get a better feel for their work and the

problems they face on the street. Matt White, crime

analyst with the Jacksonville, Florida Sheriff's Office,

recommends taking along a laptop loaded with

Geographic Information System (GIS) data. You can then

compare information about the area with the 

officers' perceptions.

Crime scenes receive a good deal of attention in serious

crimes, but not usually in ordinary crimes. You can learn a

lot by visiting them, especially when trying to understand

a particular crime problem. Comparing incident reports

with your own observations could reveal that important

details about the setting and the circumstances of

incidents might not have been recorded - perhaps

because the report form did not specifically request them.

Armed with this knowledge, you can suggest changes to

the forms to capture information that is helpful both for

detecting offenders and for thinking about how to prevent

these crimes in the future.

Try to keep abreast of new trends in crime. Read through

a batch of crime reports each week to see if there is

anything new. Try also to pay attention to failed crime

attempts (see box). Some offenders have a trial-and-error

process as they look for new ways to get something for

nothing. Those trying to cheat ticket vending machines or

ATMs may have difficulty in finding a method that works.

But when they do, the word will spread. If you know their

method, you might be able to warn officers and others.

Very often a local crime problem is also found elsewhere.

Your force may experience a rash of thefts from building

sites when this has never been a problem before. But you

can be sure that somewhere else has suffered this

problem. That's why it is important to be alert to changes

in crime targets and modus operandi. The Internet is a

good source of information about what crime others are

seeing. You should also ask your analyst colleagues in

nearby forces. They may be experiencing exactly the same

problem, with perhaps the same group of 

offenders involved.

Do not limit yourself to the police because many other

people know a lot about particular crime problems:

• City code inspectors can see blight developing before

this is apparent to others.

• Bar owners know about underage drinking, poor serving

practices and sloppy management (in other bars, of

course!).

• Principals know all too well about bullying and

vandalism on school premises.

• Small business owners are alert to problems involving

their premises. For example, a pharmacist knows what is

being stolen from his shop or whether intoxicated

people are hanging out nearby.

• Emergency room personnel see many injuries from crime

that they record but might not report to the police.

2. Be the local crime expert
Crime Analysis for Problem Solvers in 60 Small Steps

PREPARE YOURSELF

• Women's refuges or rape crisis centers know far more

about patterns of domestic violence than most 

police officers.

• Private security guards are often the first to know about

a particular incident. But they also have information that

can contribute to your general understanding of local

crime patterns.

Offenders themselves are surprising sources of

information. Although they might not admit doing

anything themselves, they are often willing to talk about

"how it is usually done." Many offenders are actually

quite talkative about the craft of offending, and will tell

you exactly how they pick targets, fence valuables, what

offenders are looking for these days, and the like. Asking

your police colleagues to obtain this information from

offenders can sometimes be very useful.

Last, victims can tell you a good deal about the crime. For

offenses such as burglary, they may not be able to give a

precise time of offense, but they can still tell you where

an offender broke in, what is missing, what room or floor

was left alone, etc.

How to become expert on crime in your area:

• Get away from your computer!

• Talk to officers about what they are seeing.

• Go on ride-alongs and sit with dispatchers.

• Visit crime scenes and examine crime reports.

• Check failed attempts to learn exactly what happened.

• Talk to city officials about specific crime problems.

• Exchange information with businesses and 

private security.

• Ask analysts in nearby cities about changes in crime

targets and methods.

• Ask officers to question offenders about their methods.

• Get information from victims about exactly when, where,

and how.

• Help to improve crime incident forms and data capture.

Learning from Unsuccessful Attempts

The Chula Vista, California Police Department was aware that the city's building boom could worsen the residential burglary

problem. The new houses were intended for affluent couples who would be out during the day when burglaries were most likely

to happen. The police, therefore, decided to examine the effectiveness of existing security precautions to see if any of these could

be built into new homes or suggested to homeowners. Cathy Burciaga, one of the department's crime analysts, compared

completed burglaries with unsuccessful attempts for an 18-month sample of 569 homes in the city. This indicated that deadbolts

should be installed on both the side and front doors of new houses. Interviews conducted with 250 victims and 50 burglars

revealed that not one burglar had tried to enter a house by breaking a double-glazed window. This led to the recommendation

that all windows in new housing be double-glazed and meet strict forced-entry standards.

Dusk to dawn light

Indoor light on

Indoor timer light

Deadbolt on front door

Deadbolt front & side doors

Outdoor motion detector

Radio/TV left on

Alarm company sign

Completed Burglaries

28%

26%

9%

28%

15%

23%

9%

19%

Unsuccessful Attempts

29%

29%

11%

25%

29%

36%

18% 

36%

Effective?*

No

No

No

No

Yes

Yes

Yes

Yes

*"Yes" means present in a larger proportion of unsuccessful attempts than completed burglaries.
33. Know what is effective (and not) in policing

E

vidence on what makes police effective points to the

vital role of crime analysis in 21st century policing.

Understanding this research can help you apply the

lessons the police profession has learned over the last

third of a century.

There has been considerable research into which police

practices are effective at reducing crime and which

practices are not effective. Recently, the National Academy

of Sciences established a panel of social science experts to

review all police research including the question of police

effectiveness. The figure is adapted from this report. The

least effective approaches to crime reduction are in the

lower left quadrant and the most effective are in the

upper right.

In the lower left corner of the figure, we have the

"standard model" of policing. This is the dominant

policing strategy in North America. The standard model is

characterized by its reliance on law enforcement and a

lack of focus. Here we find general patrolling to deter

offenders, rapid responses to a wide variety of calls for

police service, follow-up investigations of crimes, and

other law enforcement activities that make little

distinction among the characteristics of the people, places,

times, or situations. Faced with a public demand to reduce

crime, public officials and the press who are wedded to

the standard model will request more police officers,

decreases in response time, greater police visibility, higher

success rates in investigations, and more arrests. Equally

important is what the press and public officials do not call

for - increased precision as to who, what, when, where,

why, and how crimes take place, distinctions among crime

types, the involvement of other public and private

institutions to address crime, or the application of non-law

enforcement alternatives.

Some of the earliest research into police effectiveness

addressed aspects of the standard model. This research

has consistently failed to find that the standard model has

any noticeable effect on crime, disorder, or fear of crime.

Random patrol, rapid response, follow-up investigations,

and arrest policies may be very beneficial for other

purposes, but we should not expect any of these practices

to have an impact on crime or disorder. Nor is there solid

evidence that adding police to carry out these practices

will affect crime.

To have an effect on crime, research strongly suggests

that police strategies must include two elements. These

are represented on the axes of the figure. First, the

strategy must diversify its approaches to crime and

disorder. That is, policing must address crime and disorder

using a greater range of tools than simply enforcing the

law. This idea is expressed on the vertical axis. There is

evidence that working with the public, and going beyond

law enforcement, can have modest crime and disorder

reduction affects, and the more personal the police-citizen

contacts the more likely it is that they will have an effect

on crime.

The second element necessary to highly effective policing

is focus. This element is expressed in the horizontal axis of

the figure. There is generally solid evidence that

geographically concentrated enforcement at crime or

disorder hot spots can be effective, at least in the short

run. That is, focused patrolling of very small high-crime

places (e.g., street corners and block faces) has a modest

effect on crime and a large effect on disorder. This can be

accomplished with or without intensive arrest actions.

CompStat and other related innovations of the late 1990s

seek to take advantage of these findings. The Office of

Community Oriented Policing Services has published a

Problem-Oriented Guide about when crackdowns and

related tactics are and are not effective (see Read More).

If a few individuals are responsible for most crime or

disorder, then removing them should reduce crime. Though

sound in principle, the research testing this idea is very

poor so we do not know whether repeat offender

programs work in actual practice, or if they are a

seemingly promising notion that cannot effectively be

carried out.

Problem-oriented policing applies both elements -

combining the use of diverse approaches with focused

action. How effective is it? There is a large body of

evaluation evidence here applying weak-to-strong

research methods that consistently finds that this

combination does reduce crime and disorder. First, many

problem-solving efforts have been applied after

concentrated enforcement has failed to produce long

lasting effects on crime, so something else needs to be

done. In one of the earliest examples, police in Newport

News, Virginia, had been struggling with the exceptionally

high burglary rate in the New Briarfield apartments for

well over a decade. They had obtained some short-term

results from various enforcement methods, such as foot

patrols and mini-station programs. But each time the

police redeployed away from New Briarfield the burglary

rate surged. It was only after applying a problem-oriented

approach - involving citizens, the public housing authority,
Crime Analysis for Problem Solvers in 60 Small Steps

PREPARE YOURSELF

the fire department, the city codes department, and the

U.S. Department of Housing and Urban Development -

that they were able to substantially reduce burglaries.

Second, when problem-solving at drug hot spots was

compared to traditional law enforcement at drug hot

spots in a Jersey City, New Jersey, randomized experiment,

David Weisburd and Lorraine Green found that problemsolving had the greater impact. So, even though focused

law enforcement is more effective than unfocused law

enforcement, focused problem-solving is even 

more effective.

The lessons during a third of a century of research are

now clear. Effective police work requires both focused

attention and diverse approaches. The least effective

policing uses neither element. The explanation for this is

also clear. If diverse approaches are used without focus, it

is difficult to apply the appropriate approach to the places

and people who most require it. If police are focused on

hot spots, but only enforce the law, they limit their

effectiveness. A fully effective police agency must take 

advantage of the details of crime situations to reduce

crime opportunities. Crime analysts have important roles

in applying both elements - focusing with precision using

their analytical methods, and helping to craft appropriate

police tactics that fit the details of problems they have

uncovered. This makes the 21st century the century of

crime analysis in policing.

Read More:

Scott, Michael (2003). The Benefits and Consequences of

Police Crackdowns. Problem-Oriented Policing Guides.

Response Guides Series No. 1. Washington, DC: Office of

Community Oriented Policing Services. (accessible at

www.popcenter.org and www.cops.usdoj.gov).

Weisburd, David and John Eck (2004). "What Can Police

Do to Reduce Crime, Disorder and Fear?" The Annals of

the American Academy of Political and Social Science 

593: 42-65.

Adapted from National Research Council (2003), Fairness and Effectiveness in Policing: The Evidence.

Committee to Review Research on Police Policy and Practice. Edited by Wesley Skogan and Kathleen Frydl.

Washington, DC: The National Academies Press. Figure 6.1 and Table 6.1, pp. 248-249.

Effectiveness of Policing Strategies

Diversity of Approaches

Community Policing

Little or no evidence of

effectiveness

• Impersonal community policing (e.g.,

newsletters)

Weak to moderate evidence

• Personal contacts in community policing

• Respectful police-citizen contacts

• Improving legitimacy of police

• Foot patrols (fear reduction only)

Problem-oriented Policing

Moderate evidence of effectiveness

• Problem-oriented policing

Strong evidence of effectiveness

• Problem-solving in hot spots

Standard Model

Little or no evidence of

effectiveness

• Adding more police

• General patrol

• Rapid response

• Follow-up investigation

• Undifferentiated arrest for domestic

violence

Focused Policing

Inconsistent or weak

• Repeat offender investigations

Moderate to strong evidence of

effectiveness

• Focused intensive enforcement

• Hot-spots patrols

Low Focus High

Great:

Apply a diverse array of

approaches, including

law enforcement

Little:

Rely almost exclusively

on law enforcement
4

When a serious crime occurs, the police are

expected to react immediately. They must provide

help and reassurance to victims and move fast to

arrest offenders. Yet we have seen that many times the

police are not able to arrest the culprits and may not be

able to secure a conviction when they do. We have also

seen that random patrolling, which the public expects, is

not an efficient way to apprehend criminals. This means

that much police work that is carried out to meet public

expectations is of limited value in controlling crime.

If they knew these facts, people would not be content for

police to abandon patrol or down-grade their response to

serious crimes. Rather, they would expect the police to

find new and better ways to control crime, while

continuing their traditional work. In fact, this is what the

police leadership has been trying to do by experimenting

with CompStat, zero tolerance, community policing, and

problem-oriented policing (or problem-solving as it is

often called). While crime analysts have a role in all these

innovations, problem-oriented policing (POP) thrusts them

into the limelight and gives them an important team

function. That's why you should learn about it.

Herman Goldstein originated the concept of problemoriented policing in a paper published in 1979. His idea

was simple. It is that policing should fundamentally be

about changing the conditions that give rise to recurring

crime problems and should not simply be about

responding to incidents as they occur or trying to forestall

them through preventive patrols. Police find it

demoralizing to return repeatedly to the same place or to

deal repeatedly with problems caused by the same small

group of offenders. They feel overwhelmed by the volume

of calls and rush around in a futile effort to deal with

them all. To escape from this trap, Goldstein said the

police must adopt a problem-solving approach in which

they work through the following four stages:

1. Scan data to identify patterns in the incidents they

routinely handle.

2. Subject these patterns (or problems) to indepth

analysis of causes.

3. Find new ways of intervening earlier in the causal

chain so that these problems are less likely to occur in

the future. These new strategies are not limited to

efforts to identify, arrest, and prosecute offenders.

Rather, without abandoning the use of the criminal law

when it is likely to be the most effective response,

problem-oriented policing seeks to find other potentially

effective responses (that might require partnership with

others) with a high priority on prevention.

4. Assess the impact of the interventions and, if they have

not worked, start the process all over again.

SARA is the acronym used to refer to these four stages of

problem solving - Scanning, Analysis, Response and

Assessment. Later sections of this manual will discuss

these in detail, but you can already see why you have a

central role in problem-oriented policing. You are the

person most familiar with police data and you know how

best to analyze and map that data to identify underlying

patterns. You may know better than anyone else in the

department how to use data in evaluating new initiatives.

If you make it your business to become the local crime

expert, you will also know where to find other relevant

information about problems; where to find information on

the Internet and in specialist literature about successful

responses used elsewhere; how to use insights from

environmental criminology in developing a problem

analysis; and how to anticipate and measure any possible

displacement. Without your day-to-day involvement at all

four stages, the POP project will not achieve a substantial

and sustained reduction in the problem.

Problem solving can be difficult. The greatest difficulties

are found at analysis and assessment, precisely where you

could make your greatest contribution. Indeed, from the

very first, Goldstein has argued that problem-oriented

policing depends crucially on the availability of high-level

analytic capacity in the department an argument repeated

in his most recent publications. In fact, he has been very

supportive of the idea of writing this manual, which is

addressed directly to the role of the crime analyst in

problem-oriented policing.

You might agree that you have a substantial role in

problem-oriented projects, but you might ask how you

could ever succeed in that role given the realities of your

job. How could you devote the time needed for the kind

of careful analyses required? How could you make a longterm commitment to a project, when you are continually

being asked to produce statistical reports and maps

immediately, if not before? How would you ever be

accepted as an equal member of the team, especially if

you are a mere civilian? How could you function as an

equal member when your boss wants to approve every

analysis you suggest and wants to see all your work

before it leaves the unit? How could you restrain the

4. Become a POP expert
Crime Analysis for Problem Solvers in 60 Small Steps

LEARN ABOUT PROBLEM-ORIENTED POLICING

natural impatience of officers to move to a solution before

the analysis is complete? How could you persuade them

to consider solutions other than identifying and arresting

offenders? How would you deal with criticisms that you

are more interested in research than practical action? In

short, you may be wondering what planet we are living

on because it certainly resembles nothing you have seen.

These are good questions, but we believe that policing is

changing and that you can help speed up these changes.

There is slow but increasing pressure on police to become

more effective and the time is long past when chiefs

could say they would cut crime if only they had more

resources. Now, at least in larger departments, they must

make a detailed evidence-based case for these resources

and must explain precisely how they would use them.

Their performance is being watched more closely every

day, and the crime reductions that police in many cities

claim to have achieved have undermined excuses 

for failure.

In short, there is no doubt that police will become

increasingly reliant on data to acquire resources and

manage them effectively. By providing these data, you can

ride this tide of change to a more rewarding career in

policing, though you will have to work patiently to supply

timely information in a form that is helpful to the

organization. If you do this, and you remain firmly focused

on crime reduction, you and your profession will gradually

move into a more central policing role - and problemoriented policing provides you with the perfect vehicle. We

all know that policing is beset by new fads that follow hot

upon one another and almost as quickly disappear when

something new arrives. Many seasoned officers play along

for a while, waiting for management to lose interest so

that they can get back to business as usual. But problemoriented policing is not just a fad. It delivers results and is

here to stay.

Read More:

Goldstein, Herman (1979). "Improving Policing: A

Problem-Oriented Approach." Crime & Delinquency April:

234-58.

Goldstein, Herman (1990). Problem-Oriented Policing.

New York: McGraw Hill.

Goldstein, Herman (2003). "On Further Developing

Problem-Oriented Policing. In Problem-Oriented Policing.

From Innovation to Mainstream." Crime Prevention

Studies, Volume 15, edited by Johannes Knutsson.

Monsey, NY: Criminal Justice Press.
5

S

ome police managers attracted to problem-oriented

policing also apply other strategies, such as

community policing, "broken windows" policing,

intelligence-led policing, and CompStat. Depending on

how these other strategies are implemented, they may or

may not be compatible with POP. Even when

implemented in a compatible manner, they are not the

same as POP. For these reasons it is critical to understand

how POP differs from these other strategies.

Problem-oriented policing is a method for analyzing and

solving crime problems. Community policing, on the other

hand, represents a broader organizational philosophy.

Community policing includes problem-solving as

addressed in problem-oriented policing, but it also

includes the development of external partnerships with

community members and groups. Additionally, community

policing addresses organizational changes that should

take place in a police agency (such as decentralized

decision-making, fixed geographic accountability, agency

wide training, personnel evaluations) designed to support

collaborative problem-solving, community partnerships,

and a general proactive orientation to crime and social

disorder issues. Community policing is therefore more

focused on police-public interaction than is problemoriented policing and represents a broader organizational

philosophy that incorporates the principles of problemoriented policing within it. When done well, community

policing provides a strong overarching philosophy in

which to engage in POP, but community policing that fails

to incorporate the principles of POP within it is unlikely to

have a substantial impact on reducing crime.

Problem-oriented policing identifies partners whose help

is needed in dealing with specific problem. In an ideal

case, community policing does this as well. If the problem

is assaults around bus stops, a necessary partner will be

the local transit authority. If the problem is shoplifting,

then the cooperation of local businesses is needed.

Community members often identify problems. Specific

members of the public (including offenders) can have

important insights useful for problem analysis.

Community members can help implement solutions (for

example, in fitting deadbolts or not giving money to

beggars). And the success of a problem-solving effort

might be defined in terms of community reaction. But

rarely can the community at large help with the

specialized technical work involved in problem analysis,

solution development, and evaluation. In addition to

partnering around specific problems, community policing

also seeks out partnerships among the community at

large (and government organizations) in order to increase

the level of trust and general cooperation with them. In

this sense, it goes beyond the partnerships described

under problem-oriented policing. Agencies that adopt the

broader general philosophy of community policing should

be careful not to let these partnerships with a different

purpose (building trust and cooperation) dilute the more

focused problem-solving partnerships and efforts that the

community policing philosophy also encourages.

These distinctions are most easily confused when the

focus of a problem-oriented project is a deprived

neighborhood. In this case, the project should proceed by

identifying the collection of individual problems that

together make up the greater one (see Step 14). Rather

than attempting to build a relationship with the

community at large, a problem-oriented project focuses on

solving the specific problems of, say, drug houses,

commercial burglaries, and bar fights. To the extent that

members of the community become productively involved

in solving these discrete problems, they may be a rather

different group of individuals in each case. Broader

partnerships with the community could be developed in

order to build trust between police and the community

and this can make the problem-solving process easier;

however, even in the absence of widespread community

support, problems need to be systematically addressed.

It is also important to understand the difference between

problem-oriented policing and broken windows policing.

Under the former, specific solutions to the variety of

problems confronting the police emerge from careful and

detailed analysis of the contributory causes of each. By

contrast, "broken windows" advocates the same general

solution - policing incivilities and maintaining order -

whenever crime shows signs of becoming out of hand.

This approach is based on two principles, the first of

which is that small offenses add up to destroy community

life. For example, littering one piece of paper is nothing

terrible, but if everybody does it the neighborhood

becomes a dump. The second principle of broken windows

is that small offenses encourage larger ones. For example,

abandoned and boarded up properties often become the

scene for drug dealing and can spawn more serious

crimes. This important insight has led some cities to pay

much more attention to policing against small offenses.

All policing requires discretion, and broken windows

policing requires some very important decisions to be

made by officers on the street. (This is why it should not

be confused with "zero tolerance" which is a political

slogan, impossible for the police to deliver because it

would soon result in clogged courts and an alienated

5. Be true to POP
Crime Analysis for Problem Solvers in 60 Small Steps

LEARN ABOUT PROBLEM-ORIENTED POLICING

population.) One has to figure out which of the small

offenses multiply into more crimes and which do not. For

example, New York City subway system managers learned

that young men jumping turnstiles to travel free often

committed robberies within the system. Controlling the

minor crime helped reduce the major one. But the subway

managers also learned that those painting graffiti did not

normally commit more serious crimes. Although their

efforts to control graffiti were very effective (see Step 41),

they did not reduce robbery.

Problem-oriented policing also addresses these less

serious offenses even if there is no expectation that they

will lead to worse problems. Vandalism in a public park

might not increase the chances of robbery, but it does

destroy public facilities, so it is a problem that needs to be

addressed. Citizens in a neighborhood may be very

concerned about speeding, traffic congestion, or noise. As

long as these meet the criteria for a problem (Step 14)

they are addressable by POP, even if there is no

expectation that the neighborhood will deteriorate should

these go unaddressed.

Crime analysts are given a central role in intelligence-led

policing, which puts a premium on the need for sound

information to guide policing operations. However,

intelligence-led policing is primarily a methodology for

producing sound, useable intelligence. It does not guide

police through the whole process of designing and

implementing a crime reduction initiative in the way that

the SARA model is intended to do. Nor does it give a

central role to crime analysts at every stage in such an

initiative. This is why problem-oriented policing has a

great deal more to offer crime analysts and why it expects

much more of them.

Finally, problem-oriented policing is not the same as

CompStat, though they share some common features.

Both focus police attention, though CompStat as normally

practiced restricts itself to geographic hot spots while POP

can be applied to a wider array of crime concentrations.

Though both use data to drive police action, the variety of

data and depth of analysis used in POP is greater than

quick-paced CompStat targeting. CompStat uses law

enforcement tactics almost exclusively, while POP uses

these along with a wider variety of responses. CompStat

may have short-term impacts on geographic hot spots of

crime that wear off and require more enforcement. A

problem-oriented approach seeks longer-term solutions. If

CompStat is used as a "first-aid" response while POP is

applied to enact a longer-term cure, then the two

approaches can work well together.

Read More:

Wilson, James Q. and George Kelling (1982). "Broken

Windows." The Atlantic Monthly March: 29-38.

Differences Between Problem-Oriented Policing and Other Strategies

Problem-oriented

policing 

Community policing

Broken windows

Intelligence-led

policing

CompStat

Focus

Specific, recurring crime

problems

Public-police relations,

organizational changes,

problem-solving

Deteriorating

neighborhoods

The process of

collecting, analyzing,

and disseminating

intelligence 

Acute, short term

geographic crime

patterns

Objective

Remove the causes of

these problems

Proactive prevention of

crime and social

disorder and increased

public confidence in and

support of police

Halt slide of

neighborhood into

serious crime

Base policing strategies

and tactics on sound

intelligence 

Reduce crime hot spots

Rationale

Prevention is more

effective than

enforcement

Support is critical for

police effectiveness.

Organizational changes

are essential to

maintain changes,

problem-solving is a

central method to

dealing with crime and

social disorder issues

Nip trouble in the bud

Action only effective

when based on sound

intelligence

Fewer hot spots reduce

overall crime

Method

Undertake focused

action-research (SARA)

Build trust by contacts

with residents and

community meetings,

enacts organizational

changes to support

efforts, engages in

problem-solving

Policing incivilities/order

maintenance

Promote the intelligence

cycle of collection,

evaluation, collation,

analysis, and

dissemination 

Computerized hot spot

identification and

intensive patrols and

enforcement

First Steps

Identify problems

requiring attention

Appoint a community

officer for the

neighborhood, identify

problems requiring

attention, identify

organizational changes

necessary to support

efforts

Identify a deteriorating

neighborhood

Development of data

gathering, processing,

and dissemination

Build crime mapping

and geographic

accountability
Y

our department will sometimes mount a crackdown

on a particular crime such as auto crime or burglary,

and you might be asked to map these offences or

provide other data to support the operation. But these

categories are too broad for problem-oriented policing.

They include too many different kinds of crimes, all of

which need to be separately analyzed. For example, "auto

crime" could include:

• Stealing hubcaps for resale or badges for collections.

• Breaking into cars to steal items left inside.

• Breaking into cars and stealing radios and other fittings.

• Joyriding by juveniles.

• Taking a car for temporary transport.

• Stealing a car for use in another crime.

• Stealing and keeping a car.

• Stealing cars for "chopping" and sale of the parts.

• Stealing cars for resale.

• Stealing cars for export overseas.

• Carjacking.

You can see these crimes are committed for a variety of

motives, by different offenders, with varying degrees of

organization, knowledge and skills. Stealing hubcaps is

the least difficult and daring and is committed by juvenile

wanabees. Joyriding requires more courage and some

basic knowledge about starting and driving cars. Stealing

cars for export is a much more complicated crime

requiring high levels of organization, with many more

stages and people involved. The offenders are as likely to

be dishonest businessmen as career criminals. More

ruthless, hardened criminals commit carjacking.

These differences between crimes explain why the

solutions to each cannot be the same. Joyriding can be

reduced by better built-in security, which explains why

immobilizers are now bringing down overall levels of car

theft. However, immobilizers cannot prevent carjacking

because victims can be forced to hand over the keys if

these are not already in the ignition. In fact, some

commentators believe that carjacking has increased

because newer cars with ignition immobilizers are difficult to steal in the usual way. Immobilizers can also be

overcome by those with sufficient technical skill and they

may do little to reduce theft of cars for export. The

solution to this problem may lie in better port and border

controls and documents that are harder to forge.

Breaking down a larger problem of crime into smaller

categories is merely the first step in tightening the focus

of a POP project. For example, a recent POP project in

Charlotte, NC, originally focused on downtown thefts from

cars, became progressively more specific as the analysis of

the problem unfolded. First, it became clear that the

problem was concentrated in the car parks. Only 17%

involved cars parked in residences or on the streets. Then

it was found after counting parking spaces that cars in

surface lots were six times more at risk than those in

parking garages, which were generally more secure (see

Step 27). This meant the project could focus on improving

security in the surface lots through better lighting and

fencing, and more supervision by attendants. This would

be much easier than trying to reduce the already low

levels of theft in the parking garages. Tightening the focus

of a POP project in this way increases the probability of

success and uses resources effectively.

There are few rules for determining precisely the level of

specificity needed for a successful POP project. Tightening

the focus too much could result in too few crimes being

addressed to justify the expenditure of resources, though

this depends on the nature and seriousness of the crimes.

If only a few hubcaps are being stolen, then this problem

would not merit a full-blown POP project. On the other

hand, a POP project to reduce corner store robberies

could be worth undertaking, even if only a few such

robberies occur each year, because these can escalate into

worse crimes such as murder, and because they increase

public fear.

6. Be very crime specific 6

"Because so much effort has been concentrated on

crude groupings of crime types, such as burglary,

robbery or auto theft, it has been virtually impossible to

find truly common facts about the conditions which lead

to each of these groups of crimes. This implies that we

have to be very patient and try to solve the problems of

crime gradually and progressively, piece by piece."

Source: Poyner, Barry (1986). "A Model for Action".

Situational Crime Prevention, edited by Gloria Laycock

and Kevin Heal. London: Her Majesty's Stationery Office.
Specific problems in a dilapidated neighborhood or apartment complex should always be separately analyzed, but, for cost- effectiveness

reasons, solutions ought to be considered together. In the hypothetical example below, the last identified solution, a gatekeeper and

closed circuit television (CCTV) system, is the most costly of all those listed. But it is also predicted to be the most effective solution for

each problem. It might therefore be chosen as a solution to all three problems when costs might have ruled out its selection for just one

of the problems.

Crime Analysis for Problem Solvers in 60 Small Steps

Some serious crimes, such as school shootings, are so rare

that they cannot be properly addressed at the local level

by problem-oriented policing. This is because the

methodology depends upon a certain level of repetition to

permit underlying causes to be identified. For these kinds

of crimes, police forces must ensure that routine security

measures are in place and that they have a well-worked

out plan for responding to incidents.

While one should avoid beginning with a solution, some

solutions for specific crimes are so promising that they

might help define the focus of a POP project. To return to

the example of robbery at corner stores, there is good

research showing that having at least two members of

staff on duty can reduce late night robberies of these

stores. You could therefore take a look at how many

corner store robberies occur late at night in your area. If

there were enough of them, you might persuade your

department to mount a POP project focused on these late

night robberies simply because you know that an effective

solution exists.

Finally, as you learn more about a problem in the analysis

stage, you might decide that it is so similar to a related

problem that it is worth addressing the two together. For

instance, when working on a problem of assaults on taxi

drivers, you might discover that many of these are related

to robbery attempts and that it would be more

economical to focus your project on both robberies and

assaults. In this way you may identify a package of

measures that would reduce the two problems together.

LEARN ABOUT PROBLEM-ORIENTED POLICING

Barry Poyner and Barry Webb have argued that preventing residential burglaries targeted on electronic goods

requires quite different measures from those to prevent burglaries targeted on cash or jewelry. This is because they

found many differences between these two sorts of burglaries in the city they studied. When the targets were cash or

jewelry, burglaries occurred mostly in older homes near to the downtown area and were apparently committed by

offenders on foot. When the targets were electronic goods such as TVs and VCRs, the burglaries generally took place

in newer, more distant suburbs and were committed by offenders with cars. The cars were needed to transport the

stolen goods and had to be parked near to the house, but not so close as to attract attention. The layout of housing

in the newer suburbs allowed these conditions to be met, and Poyner and Webb's preventive suggestions consisted

principally of means to counter the lack of natural surveillance of parking places and roadways. Their suggestions to

prevent inner city burglaries focused more on improving security and surveillance at the point of entry.

Being More Specific about Residential Burglary

Source: Poyner, Barry and Barry Webb (1991). Crime Free Housing. Oxford: Butterworth-Architecture.

IDENTIFIED SOLUTIONS

(from least costly to most)

Trim bushes to improve surveillance ($)

Block watch scheme ($)

Alarms for elevators ($$)

Electronic access to parking lot ($$)

Installation of entry phone ($$$)

Security patrol ($$$$)

Window locks and strengthened doors for apartments ($$$$)

Gatekeeper and complex-wide CCTV cameras ($$$$$)

Separate Problems, Common Solutions

VANDALISM TO

ELEVATORS

***

 

** 

*

****

THEFTS

OF/FROM CARS

**

*

****

**

 

BURGLARIES OF

APARTMENTS

** 

*

****

**

****

$ Predicted costs * Predicted effectiveness
Within problem-oriented policing, the police are

required to: (1) carefully define specific problems

(see Step 14 for the definition of "problem"); (2)

conduct in-depth analyses to understand their causes; (3)

undertake broad searches for solutions to remove these

causes and bring about lasting reductions in problems;

and (4) evaluate how successful these activities have

been. This is a form of action research, a well-established

social science method in which researchers work

alongside practitioners, helping to formulate and refine

interventions until success is achieved. This can be

contrasted with the usual role of researchers, in which

they work apart from the practitioners, collect background

information about problems, and conduct independent

evaluations. In action research, however, the researcher is

an integral member of the problem-solving team. This is

the role of the crime analyst. Your analyses must inform

and guide action at every stage.

You will find that SARA will help you and your team keep

on track. This is the acronym formulated by John Eck and

Bill Spelman to refer to the four problem-solving stages of

Scanning, Analysis, Response and Assessment. This

process is very similar to many other analytical processes,

including the standard crime analysis process of

collection, collation, analysis, dissemination, and feedback.

By dividing the overall project into separate stages, SARA

helps to ensure that the necessary steps are undertaken in

proper sequence - for example, that solutions are not

adopted before an analysis of the problem has been

undertaken. This is a useful check on the natural tendency

to jump straight to a final response, while skimping on

definition of the problem and analysis and forgetting to

assess their impact on the problem.

Problem-solving projects can be complex. In action

research, the team is expected to persist until success is

achieved, refining and improving an intervention in the

light of what is learned from earlier experiences. The

process is not necessarily completed once the assessment

has been made. If the problem persists, or has changed its

form, the team may have to start over. This is represented

in the figure where the outer arrows describe the

feedback between assessment and scanning.

However, the four problem-solving stages do not always

follow one another in a strictly linear fashion. In fact,

projects rarely follow a linear path from the initial

scanning and analysis stages through the stages of

response and assessment. Rather, the process often has

loops, so that an unfolding analysis can result in

refocusing of the project, and questions about possible

responses can lead to the need for fresh analyses. The

longer and more complicated the project, the more loops

of this kind are likely to occur. The set of smaller inner

arrows in the figure illustrate this dynamic process. For

example, one might jump from scanning to the

implementation of a short-term emergency response to

stabilize the problem while further analysis is undertaken.

An assessment of the short-term response could add to

the analysis and contribute to the formulation of a new

response, which is then assessed. This might lead back to

scanning as new information forces a revision of the

problem definition or the discovery of new problems. The

important point is that analysis and evaluation are

meaningfully incorporated into the sequence of events

and one does not simply jump from scanning to response

and declare victory.

7. Be guided by SARA — but not led astray! 7

THE SARA PROBLEM-SOLVING PROCESS

SCANNING ANALYSIS

ASSESSMENT RESPONSE
Crime Analysis for Problem Solvers in 60 Small Steps

One of us (Clarke) recently worked with Herman Goldstein

on a project to reduce thefts of appliances from houses

under construction in Charlotte, North Carolina. The

housing developments were often in fairly isolated rural

areas and were impossible to patrol effectively. They were

difficult to secure because builders wanted to encourage

prospective buyers to tour the sites in the evenings and

on weekends. Because few offenders were ever caught,

we knew little about them or how they disposed of the

appliances. We considered a wide range of possible

solutions including storing appliances in secure containers

on site and the use of portable alarms and closed-circuit

television cameras. Then we hit on a solution being used

by some small builders - to delay installation of the

appliances until the day that the buyer took possession.

Many builders were hostile at first to the idea. Sales staff

believed that having the appliances installed made a

home more saleable, and that the absence of appliances,

if attributed to theft, might alarm purchasers about the

area they were moving into. Site supervisors felt that

delivering and installing appliances as houses were

occupied would be more difficult than batch delivery and

installation. Some erroneously believed that building

inspectors would not certify the houses as suitable for

occupancy unless appliances were in place. Others

wrongly believed that this was a mortgage requirement.

Finally, individual installation would mean that builders

could no longer arrange for building inspectors to visit a

site and issue certificates of occupancy wholesale.

Because the solution had so many advantages, we

decided to return to the analysis stage to find answers to

the builders' objections. Ultimately, this information was

useful in persuading builders to adopt the solution and

thus reduce the number of appliance thefts.

This shows how problem-oriented policing is a process in

which the gradual acquisition of data and information

informs the project, leading to more questions, to

redefinition, and even to changes in focus as it moves

along. As soon as a promising response is identified, its

costs and benefits need to be analyzed in depth. The

alternative of comprehensively exploring all available

response options runs the risk that the project will lose

momentum and the support of those involved.

Read More:

Clarke, Ronald and Herman Goldstein (2002). "Reducing

Theft at Construction Sites: Lessons from a ProblemOriented Project." Crime Prevention Studies, volume 13,

edited by Nick Tilley. Monsey, New York: Criminal Justice

Press. (accessible at: www.popcenter.org/library.htm)

Eck, John (2003). "Why Don't Problems Get Solved?"

Community Policing: Can It Work?, edited by Wesley

Skogan. Belmont, California: Wadsworth.

LEARN ABOUT PROBLEM-ORIENTED POLICING

Paul Ekblom of the British Home Office has recently

proposed a development of SARA consisting of:

Intelligence, Intervention, Implementation, Involvement,

and Impact and process evaluation. The "5 I's" are

supported by a wealth of practical concepts and tools.

SARA and the "5 I's"

A summary can be found at:

www.crimereduction.gov.ukwww.jdi.ucl.ac.uk
Most criminological theories focus on what makes

people "criminal". They find causes in distant

factors, such as child-rearing practices, genetic

makeup, and psychological or social processes. These

theories are very difficult to test; are of varying and

unknown scientific validity; and yield ambiguous policy

implications that are mostly beyond the reach of police

practice. But you will find that the theories and concepts

of environmental criminology (and of the new discipline of

crime science) are very helpful in everyday police work.

This is because they deal with the immediate situational

causes of crime events, including temptations and

opportunities and inadequate protection of targets. You

will be a stronger member of the problem-oriented team

if you are familiar with these concepts.

The problem analysis triangle (also known as the crime

triangle) comes from one of the main theories of

environmental criminology - routine activity theory. This

theory, originally formulated by Lawrence Cohen and

Marcus Felson, states that predatory crime occurs when a

likely offender and suitable target come together in time

and place, without a capable guardian present. It takes

the existence of a likely offender for granted since normal

human greed and selfishness are sufficient explanations

of most criminal motivation. It makes no distinction

between a human victim and an inanimate target since

both can meet the offender's purpose. And it defines a

capable guardian in terms of both human actors and

security devices. This formulation led to the original

problem analysis triangle with the three sides representing

the offender, the target, and the location, or place (see

inner triangle of the figure).

By directing attention to the three major components of

any problem, the inner triangle helps to ensure that your

analysis covers all three. Police are used to thinking about

a problem in terms of the offenders involved - indeed, the

usual focus is almost exclusively on how to identify and

arrest them. But POP requires that you explore a broader

range of factors and this requires information about the

victims and the places involved.

The latest formulation of the problem analysis triangle

adds an outer triangle of "controllers" for each of the

three original elements (see figure):

• For the target/victim, this is the capable guardian of the

original formulation of routine activity theory - usually

people protecting themselves, their own belongings or

those of family members, friends, and co-workers.

Guardians also include public police and private security.

• For the offender, this is the handler, someone who

knows the offender well and who is in a position to

exert some control over his or her actions. Handlers

include parents, siblings, teachers, friends and spouses.

Probation and parole authorities often augment or

substitute for normal handlers.

• For the place, the controller is the manager, the owner

or designee who has some responsibility for controlling

behavior in the specific location such as a bus driver or

teacher in a school, bar owners in drinking

establishments, landlords in rental housing, or flight

attendants on commercial airliners.

Problem Analysis Triangle

8. Use the problem analysis triangle 8

Guardian

Handler

Manager

Offender

CRIME

Place

Target/Victim
Crime Analysis for Problem Solvers in 60 Small Steps

The problem analysis triangle is the basis for another

useful analytic tool - a classification of the three main

kinds of problems that confront police and a theory about

how these problems arise. John Eck and William Spelman

have proposed classifying such problems as "wolf,"

"duck" and "den" problems:

1. Repeat offending problems involve offenders attacking

different targets at different places. These are ravenous

WOLF problems. An armed robber who attacks a series

of different banks is an example of a pure wolf problem.

Wolf problems occur when offenders are able to locate

temporarily vulnerable targets and places. The

controllers for these targets and places may act to

prevent future attacks, but the offenders move on to

other targets and places. It is the lack of control by

handlers that facilitates wolf problems.

2. Repeat victimization problems involve victims

repeatedly attacked by different offenders. These are

sitting DUCK problems. Taxi drivers repeatedly robbed in

different locations by different people is an example of a

pure duck problem. Duck problems occur when victims

continually interact with potential offenders at different

places, but the victims do not increase their

precautionary measures and their guardians are either

absent or ineffective.

3. Repeat location problems involve different offenders

and different targets interacting at the same place.

These are DEN of iniquity problems. A drinking

establishment that has many fights, but always among

different people, is an example of a pure den problem.

Den problems occur when new potential offenders and

new potential targets encounter each other in a place

where management is ineffective. The setting continues

to facilitate the problem events.

Note that pure wolf, duck, and den problems are rare.

Most problems involve a mixture. The question is, which is

most dominant in a given problem: wolves, ducks,

or dens?

When crime is occurring, all inner elements of the triangle

must be present and all outer elements weak or absent.

If potential offenders are constantly present, for example,

but crimes occur only when guardians are absent, then

rescheduling guardians might be a useful solution. Ask

yourself, "What does the problem analysis triangle look

like before, during, and after crimes?"

Understanding how problems are created by opportunities

will help you think about what might be done to: prevent

offenders from reoffending by making better use of

handlers; help victims reduce their probabilities of being

targets; and to change places where problems occur, be

these schools, taverns, or parking lots. In short, right from

the beginning, it helps you to focus data collection on

those six aspects most likely to lead to practical solutions.

STUDY ENVIROMENTAL CRIMINOLOGY

Traditional criminology seeks to improve understanding of the psychological and social forces that cause people to

become criminals in the hope of finding ways to change these causes. Crime science takes a radically different

approach. It focuses not on the reasons why criminals are born or made, but on the act of committing crime. It seeks

ways to reduce the opportunities and temptations for crime and increase the risks of detection. In doing so, it seeks

contributions from a wide range of disciplines, including psychology, geography, medicine, town planning, and

architecture. Crime science explicitly seeks to be judged by the extent to which it helps to reduce crime on our

streets, and in our homes and businesses.

What is Crime Science?

Source: Jill Dando Institute for Crime Science. (2004). www.jdi.ucl.ac.uk
F

or environmental criminologists, "opportunity makes

the thief" is more than just a popular saying; it is the

cornerstone of their approach. They believe that if

opportunity increases so will crime. To see if you agree,

consider the scenario suggested by Gloria Laycock and

Nick Tilley of the Jill Dando Institute of Crime Science:

Suppose all situational controls were to be 

abandoned: no locks, no custom controls, 

cash left for parking in an open pot for occasional 

collection, no library check-outs, no baggage 

screening at airports, no ticket checks at train 

stations, no traffic lights, etc., would there be no 

change in the volume of crime and disorder?

If you answer that of course crime and disorder would

increase, then you, too, think opportunity is a cause of

crime. Incredibly, most criminologists would not agree.

They believe that opportunity can only determine when

and where crime occurs, not whether it occurs. In their

view, whether crime occurs is wholly dependent on

offenders' propensities and these propensities collectively

determine the volume of crime in society.

In fact, crime levels are as much determined by the

opportunities afforded by the physical and social

arrangements of society as by the attitudes and

dispositions of the population. This is difficult to prove

without conducting experiments, but it would be unethical

to create new opportunities for burglary or robbery and

wait to see what happens. However, experiments have

been undertaken with minor transgressions. In the 1920s,

researchers gave children the opportunity to cheat on

tests, to lie about cheating, and to steal coins from

puzzles used. Other researchers have scattered stamped

and addressed letters in the streets, some containing

money, to see if these were mailed. In a third group of lab

experiments, subjects were instructed to "punish" others

for disobeying test instructions by delivering severe

electric shocks through the test apparatus. (In fact, no

shocks were actually delivered).

The results of these experiments support the causal role of

opportunity. Most of the subjects, even those who

generally resisted temptation, took some opportunities to

behave dishonestly or aggressively - opportunities they

would not have encountered but for their participation in

the studies. But you cannot generalize from these minor

transgressions to crimes of robbery or car theft. We,

therefore, must turn to some other sources of evidence

about the importance of opportunity in causing crime.

Suicide and opportunity. Suicide is not a crime, but

like much crime is generally thought to be deeply

motivated. However, there is clear evidence from the U.K.

that opportunity plays an important part in suicide. During

the 1950s, about half the people who killed themselves in

the U.K. used domestic gas, which contained lethal

amounts of carbon monoxide (CO). This was known as

"putting your head in the gas oven." In the 1960s, gas

began to be made from oil instead of coal. The new gas

had less CO and the number of gas suicides began to

decline. By 1968, only about 20 percent of suicides

involved gas. This is when a second change began:

manufactured gas was replaced by natural gas from the

North Sea. Natural gas contains no CO and is almost

impossible to use for suicide. By the mid-1970s, less than

1 percent of suicides in the U.K. used this method.

What is deeply surprising is that suicides did not displace

wholesale to other methods. The table shows that

between 1958 and 1976 suicides dropped by nearly 30

percent from 5,298 to 3,816. (This was during an

economic decline when suicide could have been expected

to increase and, indeed, was increasing in other European

countries.) People did not turn to other methods because

these all had drawbacks. Overdoses are much less lethal

than carbon monoxide. Hanging requires more knowledge

as well as courage. Not everyone has access to guns,

which can result in disfigurement instead of death. On the

other hand, domestic gas was readily available in most

homes. It was highly lethal and using it was bloodless and

painless. It is not surprising it was the preferred method

for so long and that when the opportunity to use it was

removed, the number of suicides declined.

9. Know that opportunity makes the thief 9
Murder and opportunity. Opportunity also plays an

important causal role in murder, as shown by a

comparison made some years ago of homicide rates in the

United States and the U.K. For 1980-84, the period

covered by the study, the overall homicide rate in this

country was 8.5 times greater than in England and Wales.

The gun homicide and handgun homicide rates were,

respectively, 63 times and 75 times as great. In the whole

of England and Wales in this period (with about 50

million people), only 57 handgun murders occurred. In the

United States, with a population of about 230 million

(less than five times greater) a total of 46,553 people

were murdered with a handgun.

These findings tended to be dismissed because the overall

crime rate in the U.S. was generally higher than it was in

England and Wales during that period. However, in the

past 15 years the overall crime rates of the two countries

have converged so that there is now little difference

between them, with the glaring exception of homicide.

There is still a much higher rate of murder in this country

because far more people here own guns, especially

handguns, than in the U.K. Even the police in the U.K. do

not routinely carry guns! So, when people fight here,

someone is much more likely to get shot than in the U.K.

Similar, but not such striking findings, emerge from

comparing murder rates in the U.S. and Canada (see box).

Taken together, these comparisons show that gun

availability (an opportunity variable) plays an important

causal role in murder.

Understanding the arguments in this section, and

accepting that opportunity causes crime, does not mean

you must deny the importance of other causes, such as

inherited personalities, broken homes, and inconsistent

discipline. But there is little you can do to change people's

personalities or the divorce rate or poor parenting.

However, you can alter the criminogenic situations in

which they find themselves. Understanding that

opportunity makes the thief will help direct your attention

to practical means of preventing crime, and help you

defend them from criticism.

Read More:

Felson, Marcus and Ronald Clarke (1998). Opportunity

Makes the Thief. Police Research Series, Paper 98.

London: Home Office

Year

1958

1960

1962

1964

1966

1968

1970

1972

1974

1976

Total

Suicides

5,298

5,112

5,588

5,566

4,994

4,584

3,940

3,770

3,899

3,816

Suicides by

Domestic Gas

2,637

2,499

2,469

2,088

1,593

988 

511

197

50

14

Percent of

Total

49.8

48.9

44.2

37.5

31.9

21.6

13.0

5.2

1.3

0.4

Crime Analysis for Problem Solvers in 60 Small Steps

STUDY ENVIROMENTAL CRIMINOLOGY

Suicides in England and Wales

1958-1977

Source: Mortality Statistics, England and Wales: Causes. London:

Her Majesty's Stationery Office, Annual

A classic study compared the rate of homicides and

assaults in Seattle (U.S.A.) and Vancouver (Canada) from

1980-1986 to determine the effect of handgun

availability on the crime rate. Although similar to Seattle

in many ways, Vancouver has a more restrictive

approach to handgun possession. The study found that

wider availability of handguns increases the rate of

homicide. The key findings were:

1. The two cities differed little in their rate of assaults.

2. The murder risk was significantly higher in Seattle 

than in Vancouver, mainly due to a five times

greater risk of being murdered with a handgun in

Seattle.

3. Rates of non-gun homicides differed little between 

the two cities.

Guns and Homicide in the 

United States and Canada

Source: Sloan, John and colleagues (1988). "Handgun

Regulations, Crime, Assaults, and Homicide." The New

England Journal of Medicine, 319: 1256-1262.
10

Whenever you analyze a crime problem or think

about solutions, try to see the crime from the

offender's perspective. Try to understand why

they commit the crime - not the distant social or

psychological causes, but the benefits they are seeking. A

radical critique of criminology pointed out 30 years ago

that is not their genes that propel bank robbers through

the doors of the bank: they rob banks because they want

to get rich.

In many cases of theft and robbery the benefits are

obvious, but they may not be clear for gang violence or

so-called "senseless" vandalism and graffiti. In fact,

graffiti can mark the territory of a juvenile gang, can

indicate where to purchase drugs, or can simply be a way

to show off. Knowing which of these reasons is dominant

helps to define the focus of a problem-solving project and

unravel the contributory factors. It can also help the

project team identify solutions. Thus, the New York City

subway authorities succeeded in eradicating graffiti only

when they understood the motivation of the "taggers,"

which was to see their handiwork on display as the trains

traveled around the system (see Step 41).

Learning how offenders commit crimes is as important as

learning why they commit them. You will find rational

choice theory helpful in thinking about these questions.

The name is misleading because the theory does not

assume that offenders plan their crimes carefully; it

assumes only that they are seeking to benefit themselves

by their crimes, which is rational enough. The theory does

not even assume that offenders succeed in obtaining the

benefits they seek. This is because they rarely have all the

information they need, they do not devote enough time to

planning their actions, they take risks, and they make

mistakes. This is how we all behave in everyday decisionmaking and is what theorists call limited or bounded

rationality.

Offenders must often decide quickly how to accomplish

their goals and how to get away without being caught.

Interviewing offenders will help you understand how they

make these decisions. (The COPS Guide on interviewing

offenders will help you think about the legal and technical

difficulties of conducting these interviews. See Read

More.) Surprisingly, it is usually not difficult to get

offenders to talk, especially if you confine yourself to the

general nature of the problem you are trying to solve, and

avoid specific questions about crimes they have

committed. Offenders are no exception to the rule that we

enjoy talking about ourselves and about the work we do.

On the other hand, always retain some skepticism as

people who habitually break the law may also habitually

exaggerate and lie.

If you cannot interview offenders, try to imagine the

course of a crime (see Step 35). What must be done at

each stage? How are targets selected? How can victims

be subdued or tricked? The police escaped? The goods

disposed of? Even if you cannot answer all these

questions about modus operandi, your attempt to enter

the offender's mind can help you think about responses.

This is not an invitation to try your hand at

psychoanalysis. Instead of delving into the offender's

unconscious you should try to understand the tangible

benefits the offender is seeking and how he must manage

the commission of crime without too much effort or risk.

This is what Paul Ekblom of the Home Office Research

Department means when he advises problem solvers to

"think thief." 

10. Put yourself in the offender's shoes

Martin Gill of Leicester University in England tells a story

of interviewing an experienced offender in prison. When

dealing with the crime that had led to his arrest, Gill

asked: "Did you think you'd get caught?" The prisoner

leaned back in his chair and gave him a long look

before saying: "I never expected to hear someone from

a university ask such a stupid question. Do you think I'd

have done it, if I thought I'd get caught?"

Paul Ekblom interviewed thieves on the London

Underground (subway system) who told him that they

would stand near signs warning that "pickpockets"

were operating. On noticing the signs, passengers

would reassuringly pat whichever pockets contained

their wallets, which was a considerable help to the

thieves.
Crime Analysis for Problem Solvers in 60 Small Steps

Another alternative to interviewing your own group of

offenders is to search the literature for reports of

interviews with similar groups of offenders. Environmental

criminologists have greatly expanded our knowledge

about the methods that criminals use by interviewing car

thieves, muggers, shoplifters, and residential and

commercial burglars. The offenders may not be quite the

same group as your own, but carefully looking at the

results of these interview studies can suggest hypotheses

that you might explore in regard to your own problem.

Read More:

Decker, Scott (2004). Using Offender Interviews to Inform

Police Problem-Solving Guide No. 3. Problem-Oriented

Guides for Police, Problem Solving Tool Series.

Washington, D.C.: Office of Community Oriented Policing

Services, U.S. Department of Justice. (Accessible at

www.popcenter.org and www.cops.usdoj.gov).

STUDY ENVIROMENTAL CRIMINOLOGY

Motives

"You are sitting there alone and you feeling light in your pocket, your rent is due, light and gas bill, you got these bill

collectors sending you letters all the time, and you say, 'I wish I had some money. I need some money.' Those are the

haints. [You haint got this and you haint got that.] Your mind starts tripping cause you ain't got no money and the

wolves are at the door... [After my last stickup] I gave my landlord some money and sent a little money off to the

electric company, a little bit off to the gas company. I still had like twenty or thirty dollars in my pocket. I got me

some beer, some cigarettes, and [spent] some on a stone [of crack cocaine]; enjoy myself for a minute" (pp. 43-44).

Advantages of robbery

"Robbery is the quickest money. Robbery is the most money you gonna get fast... Burglary, you gonna have to sell

the merchandise and get the money. Drugs, you gonna have to deal with too many people, [a] bunch of people. You

gonna sell a fifty-dollar or hundred dollar bag to him, a fifty-dollar or hundred-dollar bag to him, it takes too long.

But if you find where the cash money is and just go take it, you get it all in one wad" (pp. 51-52).

Choosing the victim

"See, I know the places to go [to locate good robbery targets]. Usually I go to all the places where dope men hang

out... but I [also have] done some people coming out of those instant tellers" (p. 78).

"That's all I done robbed is drug dealers ... they not gonna call the police. What they gonna tell the police? He

robbed me for my dope? They is the easiest bait to me. I don't want to harm no innocent people, I just deal basically

with drug dealers" (p. 64).

Violence

"Well, if [the victim] hesitates like that, undecided, you get a little aggressive and you push them ...I might take [the]

pistol and crack their head with it. 'Come on with that money and quit bullcrapping or else you gonna get into some

real trouble!' Normally when they see you mean that kind of business they ... come on out with it" (p. 109).

Armed Robbers Talking

Source: Wright, Richard and Scott Decker (1997). Armed Robbers in Action. Boston: Northeastern University Press.
11

Offenders make choices based on their perceptions

of opportunities. Understanding how offenders see

things is important to preventing crime because

almost all crime prevention involves changing offenders'

perceptions of crime opportunities. Some prevention

programs work directly on offenders' perceptions, as when

police inform offenders that they are being closely

watched. But most prevention schemes work through one

or more intermediate steps, as in property marking

schemes, for example, where residents apply window

stickers showing participation. Changes in the

environment change offender perceptions. These

perceptions influence offenders' behaviors that, in turn,

alter crime patterns.

In many cases, the preventive measures deter offenders

from further criminal activity. They can also have the

positive unintended effects of: (1) reducing crime beyond

the focus of the measures, which is known as diffusion of

benefits (see Steps 13 and 47); and (2) reducing crime

before they have actually been implemented, known as

anticipatory benefits (Step 52). However, preventive

measures do not always achieve the desired effects,

sometimes because offenders are quite unaware of the

interventions in place. For example, offenders may

continue to offend in the face of covert enforcement

because they might not perceive that their risks of being

caught have increased. In other cases, offenders may

adjust negatively to the preventive measures. These

negative adjustments include displacement and long-term

adaptation.

• Displacement occurs when offenders change their

behavior to thwart preventive actions. Displacement is

the opposite of diffusion of benefits. Displacement is a

possible threat, but it is far from inevitable. Reviews

show that many situational prevention programs show

little or no evidence of displacement, and when

displacement is found, it seldom fully offsets the

prevention benefits (Step 12).

• Adaptation refers to a longer term process whereby

the offender population as a whole discovers new crime

vulnerabilities after preventive measures have been in

place for a while. Paul Ekblom, Ken Pease, and other

researchers often use the analogy of an arms race

between preventers and offenders when discussing this

process. So, in time, we can expect many crimes that

have been reduced by preventive measures to reappear

as criminals discover new ways to commit them.

Adaptation may occur as the original offenders slowly

discover new methods, or it may occur as new offenders

take advantage of changing opportunities.

A good example of adaptation is credit card fraud (see

the Box). Another more recent example of adaptation

involves bike locks. Bike thieves discovered that they

could defeat a widely used and effective lock by using a

common and cheap ballpoint pen. But not all preventive

measures are so vulnerable to criminal ingenuity. For

example, Neal Shover has argued that technology has

brought a lasting respite from safecracking, which is now

very rare though it was once quite common.

In some circumstances preventive actions may stimulate

defiance. This occurs when offenders challenge the

legitimacy of prevention efforts and commit more crimes

rather than fewer. Police are legitimately concerned, for

example, that premature displays of force can sometimes

stimulate crowds to engage in riotous behavior, so police

often refrain from dressing in full riot gear until there is

strong evidence that serious misbehavior is likely. There is

some research evidence that defiance is more likely when

the police are perceived to be unfair and heavy handed,

and that people are more law abiding when police treat

them fairly, even if the outcome is not what people desire.

In general, defiance is not a well-documented

phenomenon, but it cannot be ruled out as a possibility,

particularly when police use enforcement as the principal

prevention tool.

Read More:

Ekblom, Paul (1997). "Gearing up Against Crime: a

Dynamic Framework to Help Designers Keep up with the

Adaptive Criminal in a Changing World." International

Journal of Risk, Security and Crime Prevention, 2: 249-

265.

(Accessible at www.homeoffice.gov.uk/rds/pdfs/risk.pdf)

11. Expect offenders to react
Crime Analysis for Problem Solvers in 60 Small Steps

STUDY ENVIROMENTAL CRIMINOLOGY

Michael Levi and his colleagues have described how a partnership between the police, the British Home Office

(similar to the U.S. Department of Justice), and the credit card issuers led to successful action in the mid-1990s to

reduce credit card frauds. The measures introduced included new lower limits for retailers for seeking authorization

of transactions and more secure methods of delivering new credit cards to consumers via the mail. As the figure

shows, there was a resulting marked reduction in fraud losses (total, lost & stolen, and mail non-receipt). In recent

years, however, credit card losses have begun to climb again. This is due principally to a growth in losses resulting

from "card not present frauds" (due to the rapid expansion of Internet sales) and in counterfeiting of cards (said to

be the work of organized gangs in East Asia).

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Offender Adaptation and Credit Card Fraud

£ millions

300-

250-

200-

150-

100-

50-

0-

Total

Lost & Stolen

Mail Non-Receipt

Card Not Present

Counterfeit Card

Application Fraud

Credit Card Fraud Losses, UK
12

P

roblem-oriented policing often tries to reduce

opportunities for crime. For example, window locks

may be fitted to prevent burglary in an apartment

complex, or closed circuit television cameras installed to

prevent thefts in parking lots. These ways of reducing

opportunities for crime often meet the same objection: all

they do is move crime around, not prevent it. This theory

of displacement sees crime as being shifted around in five

main ways:

1. Crime is moved from one place to another

(geographical).

2. Crime is moved from one time to another (temporal).

3. Crime is directed away from one target to another

(target).

4. One method of committing crime replaces another

(tactical).

5. One kind of crime is substituted for another (crime

type).

In each case, the theory assumes that offenders are

compelled to commit crime, whatever impediments they

face. The basis for the assumption is either that the

propensity to commit crime builds up and must be

discharged in the same way that sexual release is sought,

or that "professional" criminals or drug addicts must

obtain a certain income from crime to maintain their

lifestyles. There is no evidence that offenders must satiate

some deep physiological appetite to commit crimes. In

fact, there is plenty of evidence that people make choices

about whether, where, and when to offend. Whatever its

basis, the displacement assumption neglects the important

role of temptation and opportunity in crime (Step 9).

Even in the case of more committed offenders, the

displacement theory fails to give enough importance to

opportunity. Thus, research on drug addicts has shown

that they adapt to variations in the supply of drugs. Nor is

there any simple progression in drug use. Rather, addicts

might be forced to use smaller amounts or less agreeable

drugs because the supply of drugs has been cut.

As for professional criminals like bank robbers, there is no

reason to assume that they must obtain a fixed amount of

money from crime. They would surely commit fewer

robberies if these became difficult and risky, just as they

would commit more robberies if these became easy. Bank

robbers, like everyone else, may sometimes have to adjust

to reduced circumstances and be content with lower

levels of income.

This does not mean that we can ignore displacement.

Indeed, rational choice theory predicts that offenders will

displace when the benefits for doing so outweigh the

costs. For example, in the early 1990s the New York City

Police deployed its Tactical Narcotics Teams to several high

drug-dealing neighborhoods. Dealers responded by

shifting their sales locations from curbside to inside the

foyers of apartment buildings. But numerous other studies

have found that displacement did not occur at all, or only

to a limited extent. For example:

• Intensive gun patrols reduced firearms crimes in a

Kansas City, Missouri high gun-crime neighborhood

without displacing these or other crimes to 

nearby communities.

• New identification procedures greatly reduced check

frauds in Sweden, with no evidence of displacement to a

range of "conceivable" alternative crimes.

• Extensive target hardening undertaken in banks in

Australia lowered robbery rates, but there was no sign

that corner stores, gas stations, betting shops, motels, or

people in the street began to experience more robberies.

• Burglary was not displaced to nearby apartment

complexes when a problem-solving approach drove

down burglary in a high-crime apartment complex in

Newport News, Virginia.

• When streets were closed in the London neighborhood

of Finsbury Park and policing was intensified, there was

little evidence that prostitutes simply moved to other

nearby locations. According to the researchers, many of

the women working the streets in Finsbury Park were

not deeply committed to prostitution, but saw it as a

relatively easy way to make a living. When conditions

changed so did their involvement and many seem to

have given up "the game" (Step 50).

• Redesign of a trolley stop to curb robberies and assaults

resulted in a reduction in violent crime at a San Diego,

California location without shifting these crimes to other

trolley stops.

In these examples and numerous others, the offenders'

costs of displacing seemed to have outweighed the

benefits and the examples bear out the argument that

displacement occurs much less than commonly believed.

This is the consensus of four different reviews of the

12. Don't be discouraged by the displacement doomsters
Crime Analysis for Problem Solvers in 60 Small Steps

displacement literature undertaken in the United

Kingdom, Canada, the United States, and The

Netherlands. The Dutch review (the most recent one)

reports that in 22 of 55 studies from around the world in

which displacement was examined, no evidence of it was

found. In the remaining 33 studies, in which evidence of

displacement was found, only some of the crime seems to

have been displaced. In no case was the amount of crime

displaced equal to the amount prevented. And in no case

did displacement increase crime.

Displacement is usually limited because offenders have

difficulty adapting quickly. If they do make changes they

are most likely to change to places, times, targets,

methods, and crime types that are similar to those the

prevention program blocks because these are the easiest

changes for them to make. This suggests that

displacement can be predicted by anticipating the easiest

changes for offenders to make. If there are obvious easy

changes, then you should consider how to incorporate

these in your prevention plan. And if you cannot include

them, then you should consider monitoring them to detect

possible displacement.

To sum up, displacement is always a threat, but there are

strong theoretical reasons for believing that it is far from

inevitable. In addition, the studies of displacement show

that even when it does occur, it may be far from complete

and that important net reductions in crime can be

achieved by opportunity-reducing measures.

Read More:

Hesseling, Rene (1994). "Displacement: A Review of the

Empirical Literature." Crime Prevention Studies, volume

3, edited by Ronald Clarke. Monsey, NY: Criminal Justice

Press (accessible at www.popcenter.org).

STUDY ENVIROMENTAL CRIMINOLOGY

In the mid-1980s, John Eck observed a displacement

dispute within the Newport News Police Department

(VA). A crackdown on a street corner marijuana market

resulted in the market's closure. Some police officials

asserted that the offenders had merely moved to a

nearby corner to deal drugs. However, close inspection

by other officers revealed several important facts:

• The nearby corner dealers were selling heroin, not

marijuana.

• None of the offenders from the marijuana market

were found at the heroin market.

• The heroin market was a much smaller scale

operation.

• It predated the opening of the marijuana market.

The claims of displacement were probably due to

selective perception. Prior to the marijuana market,

street corner drug dealing had been low key and did

not attract much public notice. Consequently, drug

markets were not a high police priority. When

neighborhood members complained about the

marijuana market, greater attention was paid to other

drug markets as well.

Claims of Displacement Often Evaporate under

Closer Scrutiny
13

R

esearchers looking for displacement have sometimes

found precisely its reverse. Rather than finding that

crime has been pushed to some other place or time,

they have found that crime has been reduced more widely

than expected, beyond the intended focus of the

measures. This is a relatively recent discovery, but already

many examples exist:

• As expected, electronic tagging of books in a University

of Wisconsin library resulted in reduced book thefts.

However, thefts of videocassettes and other materials

that had not been tagged also declined.

• When a New Jersey discount electronic retailer

introduced a regime of daily counting of valuable

merchandise in the warehouse, employee thefts of these

items plummeted - but thefts also plummeted of items

not repeatedly counted.

• When LoJack vehicle tracking systems were introduced in

six large cities, rates of theft declined citywide, not just

for car owners who purchased the devices.

• Simon Hakim and his colleagues at Temple University

have shown that widespread ownership of burglar

alarms in an affluent community near Philadelphia

resulted in reduced burglary rates for the community 

at large.

• When red light cameras were installed at certain

junctions in Strathclyde, a large city in Scotland, not only

did fewer people run the lights at these locations, but

also at other traffic lights nearby. (In a smaller city, with

more local traffic, this effect might be short-lived as

people learned exactly which junctions had cameras.) 

• The implementation of added security for houses that

had been repeatedly burgled on a U.K. public housing

estate in Kirkholt reduced burglaries for the whole of

the estate, not just for those houses given 

additional protection.

These are all examples of the "diffusion of benefits"

resulting from crime prevention measures. It seems that

potential offenders may be aware that new prevention

measures have been introduced, but they are often unsure

of their precise scope. They may believe the measures

have been implemented more widely than they really

have, and that the effort needed to commit crime, or the

risks incurred, have been increased for a wider range of

places, times, or targets than really is the case. This means

that diffusion can take several forms, paralleling the

different kinds of displacement (see table).

Diffusion of benefits is a windfall that greatly increases

the practical appeal of situational crime prevention, but

we do not yet know how to deliberately enhance it. One

important method may be through publicity. A publicity

campaign helped to spread the benefits of video

surveillance cameras across an entire fleet of 80 buses in

the North of England, although these were installed on

just a few of the buses. One of the buses with the

cameras was taken around to schools in the area to show

students they could be caught if they misbehaved and

vandalized the bus, and the first arrests resulting from the

cameras were given wide publicity in the news media.

13. Expect diffusion of benefits

Displacement and Diffusion of Benefits for Burglary of Apartments

Definition

Geographic change

Time switch

Switching object of offending

Change in method of offending

Switching crimes

Displacement

Switch to another building

Switch from day to evening

Switch from apartments to

houses

Switch from unlocked doors to

picking locks

Switch from burglary to theft

Diffusion

Reduce burglaries in targeted

building and in nearby buildings

Reduce burglaries during day

and evening

Reduce burglaries in apartments

and houses

Reduction in attacks on locked

and unlocked doors

Reduction in burglary and theft

Type

Geographical

Temporal 

Target 

Tactical

Crime Type
Crime Analysis for Problem Solvers in 60 Small Steps

We should expect the diffusion of benefits to decay when

offenders discover that the risks and effort of committing

crime have not increased as much as they had thought.

Research has shown that this occurred in the early days of

the breathalyzer in the U.K., which had a much greater

immediate impact on drunk driving than expected, given

the actual increase in the risk of getting caught. However,

as drivers learned that the risks of being stopped were

still quite small, drunk driving began to increase again.

This may mean that ways will have to be found of

keeping offenders guessing about the precise levels of

threat, or about how much extra effort is needed if they

are to continue with crime.

At a practical level, diffusion is important as a counterargument to displacement from those resisting the

introduction of preventive measures. And you will certainly

encounter many of those! Second, it is important that you

plan your evaluation to take account of diffusion. Ways to

do this are discussed in Step 51, by using two sets of

control areas, both near and more distant. Otherwise, you

might find that people question the effectiveness of the

preventive initiative on grounds that crime fell across a

broader area than was targeted.

Read More:

Clarke, Ronald and David Weisburd (1994). "Diffusion of

Crime Control Benefits: Observations on the Reverse of

Displacement". Crime Prevention Studies, volume 2.

Monsey, NY: Criminal Justice Press

(accessible at www.popcenter.org).

STUDY ENVIROMENTAL CRIMINOLOGY

A new head of security at the University of Surrey in the U.K. decided to deal with a plague of thefts in the

university's parking lots by introducing video surveillance (or CCTV - closed-circuit television). He installed a CCTV

camera on a mast to provide surveillance of the parking lots. As the diagram shows, the camera could not provide

surveillance equally for all four parking lots because buildings obscured its view of parking lot 1.

It might have been expected, therefore, that if the camera had any value in preventing crime this would only be for

the parking lots it covered adequately. It might also have been expected that crime would be displaced by the

camera from these parking lots to the one not given proper surveillance. In fact, in the year following the

introduction of the camera, incidents of theft and vandalism in the lots were cut in half, from 138 in the year prior to

65 in the year after. Incidents declined just as much in parking lot 1, not covered by the cameras, as in the other

three lots. This diffusion of the benefits of the video surveillance probably resulted from potential offenders being

aware that it had been introduced at the university, but not knowing its limitations. Many probably decided that it

was no longer worth the risk and effort of going to the university parking lots to commit crime.

Diffusion of Benefits and Video Surveillance in a University's Parking Lots

Source: Poyner, Barry (1997). "Situational Prevention in Two Parking Facilities". Situational Crime Prevention:

Successful Case Studies, edited by Ronald V. Clarke. Monsey, NY: Criminal Justice Press.

2

3 4

1

CCTV

Security Gate

Parking Lots

University Buildings
A

problem is a recurring set of related harmful events

in a community that members of the public expect

the police to address. This definition draws

attention to the six required elements of a problem:

Community; Harm; Expectation; Events; Recurring; and

Similarity. These elements are captured by the 

acronym CHEERS:

• Community. Members of the public must experience

the harmful events. They include individuals, businesses,

government agencies, and other groups. Only some -

not all or most - community members need experience

the problem.

• Harmful. People or institutions must suffer harm. The

harm can involve property loss or damage, injury or

death, serious mental anguish, or undermining the

capacity of the police (as in repeat fraudulent calls for

service). Illegality is not a defining characteristic of

problems. Some problems involve legal behavior that

the police must address. Noise complaints arising from

the impact of legitimate commercial activity on

neighboring residents is a common example. Some

problems are first reported as involving illegal behavior,

but on closer inspection do not involve illegalities. If

such reports meet all the CHEERS criteria, they 

are problems.

• Expectation. Some members of the community must

expect the police to address the causes of the harm

(their numbers do not have to be large). Expectation

should never be presumed, but must be evident through

processes such as citizen calls, community meetings,

press reports, or other means. This element does not

require the police to accept at face value the public's

definition of the problem, their idea of its causes, or

what should be done about it. The public may be

mistaken as to its cause and characteristics. It is the

role of analysis to uncover the causes.

• Events. You must be able to describe the type of event

that makes up the problem. Problems are made up of

discrete events. Examples of events include a break-in

at a home, one person striking another, two people

exchanging money and sex, or a burst of noise. Most

events are brief, though some may involve a great deal

of time - some frauds, for example.

• Recurring. These events must recur. Recurrence may

be symptomatic of acute troubles or a chronic problem.

Acute troubles suddenly appear, as in the case of a

neighborhood with few vehicle break-ins suddenly

having many such break-ins. Some acute troubles

dissipate quickly, even if nothing is done. Others can

become chronic problems if not addressed. For this

reason, acute troubles should be investigated to

determine if they signal something more entrenched.

Chronic problems persist for a long time, as in the case

of a prostitution stroll that has been located along one

street for many years. Unless something is done, the

events from chronic problems will continue to occur.

• Similarity. The recurring events must have something in

common. They may be committed by the same person,

happen to the same type of victim, occur in the same

types of locations, take place in similar circumstances,

involve the same type of weapon, or have one or more

other factors in common. Without common features, you

have an arbitrary collection of events, not a problem.

Common crime classifications - such as used by the

Uniform Crime Reports - are not helpful. Vehicle theft,

for example, includes joyriding, thefts for chop shops,

thefts for export to other countries, thefts for use in

other crimes, and a host of other dissimilar events. So a

cluster of vehicle thefts may not be a single problem.

More information is needed. With common features, we

have a pattern of events that could indicate a problem -

for example, thefts of minivans in suburban

neighborhoods to be used as gypsy cabs in the 

inner city.

Problems need to be examined with great specificity (see

Steps 6 and 15) because small details can make a

difference between a set of circumstances that gives rise

to harmful events, and a set of circumstances producing

harmless events. CHEERS suggests six basic questions

you need to answer at the scanning stage:

• Who in the community is affected by the problem?

• What are the harms created by the problem?

• What are the expectations for the police response?

• What types of events contribute to the problem?

• How often do these events recur? 

• How are the events similar?

1414. Use the CHEERS test when defining problems
Crime Analysis for Problem Solvers in 60 Small Steps

Not everything the police are asked to address is a

problem. CHEERS can help identify demands that are not

problems. We are using the term "problem" in the

technical, POP sense, not as we would in everyday

speech. So things that are not problems may be

troublesome and may require police attention. These are

as follows:

• Single events. A single event, regardless of how

serious, is not a problem unless there is a reasonable

prospect that another similar event will occur if nothing

is done. A single event may deserve investigation or

some other police action, but problem solving cannot be

applied to isolated events because nothing can be

prevented.

• Neighborhoods. Small areas, such as city centers or

particular residential apartment complexes, sometimes

get reputations as problems, but these neighborhoods

are seldom problems. Rather they are usually areas

containing several problems. The individual problems

might be related, but not always. Tackling an entire area

as a single problem increases the complexity of the

effort and reduces the chances you will find effective

responses. Instead, you should identify specific problems

within a neighborhood and tackle them individually. If

the problems are linked (e.g., the street network

contributes to several problems) then tackling the link

might be helpful. Do not assume problems are linked

just because they are near each other. In some cases, of

course, there may be common solutions to distinct

problems (see Step 6).

• Status conditions. Truant schoolchildren, bored

teenagers, vagrant adults, and convicted criminals are

not problems because of their status of not being in

school, having nothing to do, not being employed, or

having been found guilty of an offense. A community

might expect the police to do something about them,

but status conditions lack the characteristics of harm

and events. Some of these people may play a role in

problems, as targets, offenders, or in some other

capacity, but that does not make them a problem.

Defining a problem by status conditions is evidence of

lack of precision and a need to examine the issue in

greater depth. Status conditions may point to pieces of

a larger problem.

Always use the CHEERS test - does the possible problem

have all six elements? If it does not, it is probably not a

suitable focus for a problem-oriented policing project.

SCAN FOR CRIME PROBLEMS
B

ecause local police have to deal with a wide range

of problems that meet the CHEERS definition (Step

14) we have developed a classification for these

problems. This classification scheme can help you precisely

define the problem. It helps separate superficially similar

problems that are really distinct. It also allows you to

compare your problem to similar problems that have

already been addressed, and it helps identify important

features for examination. For example, an extensive set of

guides to addressing common problems are available from

the Office of Community Oriented Policing Services and

the Center for Problem-Oriented Policing websites (Step

19). Knowing the type of problem you are investigating

can help you identify guides that might be helpful, even if

they do not directly address your problem. The

classification scheme is based on two criteria: the

environments within which problems arise, and the

behaviors of the participants. (The scheme is different

from the wolf/duck/den classification in Step 8, which is a

classification of persistent problems.) 

Environments regulate the targets available, the

activities people can engage in and who controls the

location. Specifying an environment allows comparisons of

environments with and without the problem.

Environments have owners who can be important for

solving the problem (see Step 44). There are 11 distinct

environments for most common police problems:

• Residential - Locations where people dwell. Houses,

apartments, and hotel rooms are examples. Though most

are in fixed locations, a few are mobile, such as

recreational vehicles.

• Recreational - Places where people go to have a good

time. Bars, nightclubs, restaurants, movie theaters,

playgrounds, marinas, and parks are examples.

• Offices - Locations of white-collar work where there is

little face-to-face interaction between the workers and

the general public. Government and business facilities

are often of this type. Access to these locations is 

often restricted.

• Retail - Places for walk-in or drive-up customer traffic

involving monetary transactions. Stores and banks 

are examples.

• Industrial - Locations for processing of goods. Cash

transactions are not important activities in these

environments and the public is seldom invited. Factories,

warehouses, package-sorting facilities are examples.

• Agricultural - Locations for growing crops and 

raising animals.

• Education - Places of learning or study, including day

care centers, schools, universities, libraries, and place

of worship.

• Human services - Places where people go when

something is wrong. Courts, jails, prisons, police stations,

hospitals and drug treatment centers are examples.

• Public ways - Routes connecting all other environments.

Roads and highways, foot-paths and bike trails, and

drives and parking facilities are examples.

• Transport - Locations for the mass movement of people.

These include buses, bus stations and bus stops,

airplanes and airports, trains and train stations, ferries

and ferry terminals, and ocean liners and piers.

• Open/transitional - Areas without consistent or regular

designated uses. These differ from parks in that they

have not been designated for recreation, though people

may use them for this. Transitional areas include

abandoned properties and construction sites.

Behavior is the second dimension for classifying a

problem. Specifying behaviors helps pinpoint important

aspects of harm, intent, and offender-target relationships.

There are six types of behavior:

• Predatory - The offender is clearly distinct from the

victim and the victim objects to the offender's actions.

Most common crimes are of this type. Examples include

robbery, child abuse, burglary, bullying, and theft.

• Consensual - The parties involved knowingly and

willingly interact. This typically involves some form of

transaction. Examples include drug sales, prostitution,

and stolen goods sales. Note, however, that assaults on

prostitutes are predatory behaviors.

• Conflicts - Violent interactions involving roughly coequal

people who have some pre-existing relationship. Some

forms of domestic violence among adults involve this

type of behavior, though domestic violence against

children and the elderly is classified as predatory

because the parties involved are not coequal.

• Incivilities - Offenders are distinguishable from victims

but the victims are spread over a number of individuals

and the harms are not serious. Many concerns that are

1515. Know what kind of problem you have
Crime Analysis for Problem Solvers in 60 Small Steps

annoying, unsightly, noisy, or disturbing, but do not

involve serious property damage or injury fall into this

category. Loud parties are an example. Whether

vandalism fits in this category depends on the details.

Some forms of vandalism are predatory. Some

incivilities are troublesome regardless of the

environment, while others are only troublesome in

specific environments.

• Endangerment - The offender and the victim are the

same person or the offender had no intent to harm the

victim. Suicide attempts, drug overdoses, and vehicle

crashes are examples.

• Misuse of police - A category reserved for unwarranted

demands on the police service. False reporting of crimes

and repeated calling about issues citizens can handle

themselves are examples. This is a category of last resort

- for use when the sole harm stemming from the

behavior is the expenditure of police resources and

when none of the other categories fit.

The table shows the full classification. A problem is

classified by putting it in the cell where the appropriate

column intersects with the appropriate row. So, for

example, the 2001 Tilley Award winner dealt with glass

bottle injuries around pubs, a conflict-recreational

problem (A). Officers in San Diego had to deal with repeat

fraudulent calls of gang member threats at a convenience

store (B). Notice how this differs from the 2003 Goldstein

award runner-up, addressing stores selling alcohol to

minors in Plano, Texas (C). The 2002 Goldstein Award

winner dealt with motor vehicle accidents involving

migrant farm workers, an endangerment-public ways

problem (D). The 1999 Goldstein Award winner dealt

with litter and vagrancy, a public way/incivility problem

(E). Consider the difference between a problem of street

corner drug sales (F) and a robbery-retaliatory shooting

problem stemming from disputes between the dealers (G).

These two problems overlap, but they are not the same.

Though most problems fit into a single cell, on occasion a

problem might involve multiple behaviors or

environments. For example, the Staffordshire Police

(England) had a problem created when protesters

occupied abandoned buildings along a construction right

of way. These were open/transitional environments. The

protests involved incivilities, but the tactics for occupying

these buildings also posed a danger to the protesters.

Thus, endangerment was another relevant behavior (H in

the table). Though multiple types of behaviors or

environments are sometimes needed, excessive use of

multiple types can lead to imprecision.

By classifying problems, police agencies can compare

separate problem-solving efforts that occur in the same

environments and involve the same category of behavior.

Are there common analysis issues or effective responses

to these problems? Do analysis and response issues for

problems of this type differ from other types of problems?

Answering questions like these can improve problem

solving as well as problem-solving training, and help us

increase our understanding of what might work for

different types of problems in different types 

of environments.

Read More:

Eck, John and Ronald Clarke (2003). "Classifying

Common Police Problems: A Routine Activity Approach."

Crime Prevention Studies, volume 16, edited by Martha

Smith and Derek Cornish. Monsey, NY: Criminal 

Justice Press.

SCAN FOR CRIME PROBLEMS

BEHAVIORS

A Classification Scheme for Common Problems Facing Local Police

Predatory

G

Consensual

C

F

Conflicts

A

Incivilities

E

H

Endangerment

D

H

Misuse of Police

B

ENVIRONMENTS

Residential

Recreational

Offices

Retail

Industrial

Agricultural

Educational

Human service

Public ways

Transport

Open/Transition
While the problem analysis triangle (Step 8)

identifies the three essential elements of crime, it

does not explain how offenders find suitable

targets. According to Marcus Felson, they do this in three

main ways:

1. Through personal knowledge of the victim (your

neighbor's son might know when you are away from

your house).

2. Through work (a burglar working as a telephone

engineer might overhear that you will be taking

vacation next week).

3. Through overlapping "activity spaces."

The concept of activity spaces is central to crime pattern

theory, which was developed by the Canadian

environmental criminologists Pat and Paul Brantingham

(see figure). They use the concept to describe how

offenders find targets in the course of their daily routines.

Starting with a triangle, they consider offenders going

from home to work to recreation. Around each of these

three nodes and along each of these three paths

(excepting a buffer zone where they might be recognized)

offenders look around for crime opportunities. They may

find these a little way off the path, but they usually do not

go far beyond the area they know. This is because it is

easier to commit crimes in the course of their daily routine

than by making a special journey to do so.

The Brantinghams also use the term edges to refer to the

boundaries of areas where people live, work, shop, or

seek entertainment. Some crimes are more likely to occur

at these edges - such as racial attacks, robberies, or

shoplifting - because this is where people from different

neighborhoods who do not know each other come

together. In an early study, the Brantinghams found that

residential burglaries in Tallahassee, Florida tended to

cluster where affluent areas bordered on poor areas. Their

explanation was that the affluent areas provided

attractive targets to burglars from the poorer areas, but

the burglars preferred not to venture too far into them

because they were unfamiliar with the territory and might

be recognized as not belonging there. They would also be

more vulnerable because they would have further to travel

with the proceeds of the crime.

The paths that people take in their everyday activities and

the nodes they inhabit explain risks of victimization as

well as patterns of offending. This is why the

Brantinghams and other crime pattern theorists pay so

much attention to the geographical distribution of crime

and the daily rhythm of activity. For example, these

researchers generate crime maps for different hours of the

day and days of the week, linking specific kinds of crimes

to commuter flows, school children being let out, store

closing hours, or any other process that moves people

among nodes and along paths. Pickpockets and some

shoplifters seek crowds, while other offenders pay closer

attention to the absence of people. For example, the flow

of people to work generates a counterflow of burglars to

residential areas, taking advantage of the commuters'

absence. The flow of workers home at night and at

weekends produces a counterflow a few hours later of

burglars targeting commercial and industrial sites.

Many studies have shown that the journey to crime is

typically very short - offenders generally commit crimes

within 1 or 2 miles of their homes. For example, Andy

Brumwell, a crime analyst with the West Midlands Police,

one of the U.K.'s largest police forces, has recently

completed an analysis of 258,074 crime trips made over a

2-year period. He found the following:

• About half the journeys were less than a mile. (In most

U.S. studies the journeys might be a little longer because

of lower population densities and greater access to

vehicles.) 

• Distance traveled varied with the offense. For example,

shoplifters tended to travel further than many other

kinds of offenders.

• Females traveled further than males, possibly because

many committed shopliftings.

• Individual offenders varied considerably in crime trips.

Some usually committed crimes in their local

neighborhoods. Others traveled further, particularly

when working with co-offenders.

• The youngest offenders committed crime very close to

home, while those in their 20s traveled the furthest.

Susan Wernicke, a crime analyst with the City of Overland

Park, Kansas, presented more detailed information on

juveniles at the National Institute of Justice's 2000

National Crime Mapping Conference in San Diego,

California. She showed that in Overland Park the 11-yearolds arrested had committed crimes an average of 1.05

miles from home. This distance gradually increased with

age, and by age 17 was 2.7 miles. She attributed part of

the increase to greater access to cars.

1616. Study the journey to crime
Crime Analysis for Problem Solvers in 60 Small Steps

You can use the concepts of crime pattern theory to

understand crime in your jurisdiction. You should try to

piece together offender and offense patterns by finding

nodes, paths, and edges. You can begin to distinguish

between how offenders search for crime and when they

find it by accident. You can find where offenders are

absent and where they congregate in hot spots and think

about the reasons for this (Step 17). You will find that

very local crime patterns tell the story. Thus a high-crime

district will have some streets with no crime at all and

some addresses which generate most of the problem.

Residents may know it is fairly safe to walk down one

street but not to walk down another. They may even

choose one side of the street over the other. If residents

know their local turf this well, what's to stop you from

finding out about it? Crime pattern theory helps you do

just that, and it will help to define a specific problem at

the scanning stage and understand the contributory

causes at analysis.

Read More:

Brantingham, Patricia and Paul (1993). "Environment,

Routine, and Situation: Toward a Pattern Theory of

Crime." Routine Activity and Rational Choice, Advances

in Criminological Theory, volume 5, edited by Ronald

Clarke and Marcus Felson. New Brunswick, NJ:

Transaction Publishers.

Felson, Marcus (2002). Crime and Everyday Life. Thousand

Oaks, CA: Sage.

Wiles, Paul and Andrew Costello (2000). The Road to

Nowhere: The Evidence for Travelling Criminals. Home

Office Research Study 207. London: Home Office

(accessible at www.homeoffice.gov.uk) 

SCAN FOR CRIME PROBLEMS

Kim Rossmo prepared this diagram to represent the Brantinghams' theory. It shows an offender's activity space (residence, work, recreation, and the

travel routes between them), the buffer zone close to the home in which offenders do not usually commit crimes, and five potential target areas (for

example, parking lots). Where an offender's activity space intersects a target area, this is where crimes happen (crosses). Note that in this example no

crimes occur around the offender's workplace, because there are no suitable targets there. Also, there are two target areas with no crimes in them

because this offender is not aware of those places.

Andy Brumwell has developed the "self-containment

index," which looks at the percentage of crimes in an

area that is committed by offenders who also live in

that area. A value of 100 indicates that local offenders

are responsible for all the crimes, whereas a value of

zero indicates that local offenders commit none of

them. This value should be calculated when analyzing a

local problem. Whether predators are local or come

from a distance will have an influence on the type of

situational crime prevention measures that could be

successfully introduced. For example, closing streets in a

particular neighborhood will only be effective if many of

the offenders drive to the neighborhood to commit

crime.

The Journey to Crime and the Self-Containment

Index

Brantingham Crime Pattern Theory

Residence

Crime Sites

Work

Activity Space

Recreation

Target Areas

Buffer Zone

Source: Rossmo, Kim (2000). Geographic Profiling. Boca Raton, FL: CRC Press.
A

nalysts often examine hot spots by use of

geography alone. This can often be a useful

starting point, but to reduce or eliminate the hot

spot you must look deeper to understand why it is a hot

spot. We focus on developing an understanding of the

processes that create hot spots. Later, in Steps 23 and

55, we examine how to analyze and map hot spots

without letting your mapping software call the shots. As

we have seen in previous steps, small areas - places - are

critical to understanding many problems and developing

effective responses. We, therefore, focus on hot spot

places in this step. In later steps we will build on this

idea to examine hot spot streets and areas.

There are three kinds of hot spot places, each with its

own underlying causal mechanisms:

• Crime generators are places to which large numbers

of people are attracted for reasons unrelated to criminal

motivation. Providing large numbers of opportunities for

offenders and targets to come together in time and

place produces crime or disorder. Examples of

generators include shopping areas, transportation hubs,

festivals, and sporting events. The large number of crime

or disorder events is due principally to the large number

of place users and targets.

• Crime attractors are places affording many criminal

opportunities that are well known to offenders. People

with criminal motivation are drawn to such locales. In

the short run, offenders may come from outside the

area, but over longer time periods, and under some

circumstances, offenders may relocate to these areas.

Prostitution and drug areas are examples. Some

entertainment spots are also well known for allowing

deviant activity. Such places might start off being known

only to locals, but as their reputation spreads increasing

numbers of offenders are drawn in, thus increasing the

number of crime and disorder events.

• Crime enablers occur when there is little regulation of

behavior at places: rules of conduct are absent or are

not enforced. The removal of a parking lot attendant, for

example, allows people to loiter in the parking area. This

results in an increase in thefts from vehicles. This is an

example of an abrupt change in place management.

Sometimes place management erodes slowly over time,

leading to problem growth. Crime enablers also occur

with the erosion of guardianship and handling. For

example, if parents attend a play area with their children

they simultaneously protect the children (guardianship)

and keep their children from misbehaving (handling). If

parenting styles slowly change so that the children are

increasingly left to themselves, their risk of victimization

and of becoming offenders can increase.

Patricia and Paul Brantingham suggest that areas can be

crime neutral, i.e., they attract neither offenders nor

targets, and controls on behaviors are adequate. These

areas tend to have relatively few crimes, and the crimes

tend to be relatively unpatterned. For this reason, crimeneutral areas seldom draw police attention. Though they

seldom require crime analysis, they are important because

they provide a useful comparison to the other types of

areas. Comparing crime-neutral areas, for example, to a

hot spot can help identify the differences that create the

troubles in the crime generator, crime attractor, or crime

enabler. Case-control studies (Step 32) are useful for 

this purpose.

In summary, when a crime or disorder hot spot becomes a

greater problem it is generally because the number of

targets has increased, the number of offenders taking

advantage of the hot spot have increased, or because the

level of control being exercised at the site declined. Often,

all three are at work. Shoppers might increase in an area,

for example, due to new roads. This might lead to

increased thefts as offenders take advantage of the new

theft opportunities. Successful offending might attract new

offenders. Increased offending might cause the number

of shoppers to decline. This removes guardianship

(shoppers). But it has another effect. It could reduce

place management as the resources of the businesses

decline. So, a problem that started out as a crime

generator evolved into a crime attractor and then into a

crime enabler.

We can compare numbers and rates to diagnose which of

these mechanisms may be operating. Dividing the crimes

in question by the number of possible crime targets

creates rates (Step 27). This is often expressed as the

number of crimes per 100 targets available. So, for

example, if a parking lot has 15 car break-ins during a

year, and the lot contains 150 spaces and operates at

near capacity, its break-in rate is 15/150 or .1. This

translates to 10 break-ins per space per year. Note that

this analysis is only useful if the lot is operating near

capacity. If only 50 spaces are used on most days, then

the rate is three times as high (15/50=.3 or 30 break-ins

per vehicle per year).

1717. Know how hot spots develop
Crime Analysis for Problem Solvers in 60 Small Steps

Table 1 illustrates the differences in ranking the

importance of hot spots depending on whether numbers

or rates are used. Place A is the "hottest" spot in terms

of numbers but second in terms of rates, and place C goes

from third hottest to first when one switches from

numbers to rates.

Let's look at how hot spot mechanisms generate

indicative combinations of numbers and rates. Crime

generators have many crimes, but as their number of

targets is high, they have low crime rates (Place B in Table

1). Crime attractors also have many crimes, but as they

have relatively few targets, their crime rates are high

(Place A). Crime enablers, with their weakened behavior

controls, tend to be unattractive to targets. However,

those few available targets have high risks. So a place

with relatively few crimes but a high crime rate suggests a

crime enabler (Place C). Finally, the number of crimes at

crime-neutral locations will be low, so even if the number

of targets is not particularly great, their crime rate will

also be low (Place D). Table 2 summarizes 

these relationships.

The rankings of numbers and rates are relative, so this

process is useful for comparison purposes. And there may

be multiple mechanisms operating. Low behavioral

controls (enabler) may also attract offenders (attractor),

for example. Nevertheless, such comparisons provide an

early indicator of how to proceed and establish

hypotheses for later examination (see Step 20). Such

analysis will help suggest the types of responses that

could be effective. This is summarized in Table 3.

Read More:

Brantingham, Patricia and Paul (1995). "Criminality of

Place: Crime Generators and Crime Attractors". European

Journal on Criminal Policy and Research 3(3):1-26.

SCAN FOR CRIME PROBLEMS

A

B

C

D

341

148

117

28

898

1,795

243

638

.350

.082

.481

.044

35

8

48

4

Table 1: Numbers and Rates

Place Crimes Targets Rate Per 100

targets

Crime Attractors

Crime Generators

Crime Enabler

Crime Neutral

Number

High

High

Low (High)

Low

Rate

High

Low

High

Low

Table 2: Diagnosing Hot Spot Mechanisms

Hot spot type

Crime Generator

Crime Attractor

Crime Enabler

Cause

Many unprotected targets

Attracts offenders

Erosion of controls

Type of Response

Increase protection

Discourage offenders from

coming

Restore guardianship,

handling or place

management

Questions to Answer

In what circumstances are

targets vulnerable?

How can vulnerability be

changed?

What is attracting

offenders?

How can this be changed?

Who could control

behaviour?

How can they be

encouraged to exert

controls?

Table 3: What To Do about Worsening Hot Spots
A

very important principle of crime prevention is that

crime is highly concentrated on particular people,

places, and things. This suggests that focusing

resources where crime is concentrated will yield the

greatest preventive benefits. These concentrations (dealt

with in more detail in later steps) have attracted labels

that are becoming well known to most crime analysts:

• Repeat Offenders In Wolfgang's famous Philadelphia

cohort, about 5 percent of all offenders in the study

were responsible for more than 50 percent of the

crimes.

• Repeat Victims According to the British Crime Survey,

repeat victims (just over 4 percent of all victims) endure

40 percent of the crimes reported in the survey (see

Step 29).

• Hot Spots In the landmark paper that put this concept

on the map, so to speak, Lawrence Sherman and

colleagues found that 6 percent of the addresses in

Minneapolis accounted for 60 percent of the calls for

police service.

• Hot products Annual data produced by the Highway

Loss Data Institute show that theft claims for some

automobile models are as much as 30 times greater

than for other cars (see Step 31).

• Risky Facilities In Danvers, Massachusetts, 3 out of 78

stores (5 percent) accounted for 55 percent of

shoplifting incidents reported to the police (see 

Step 28).

This kind of concentration is not peculiar to crime and

disorder, but is almost a universal law. A small portion of

the earth's surface holds the majority of life on earth. Only

a small proportion of earthquakes cause most of the

earthquake damage. A small portion of the population

holds most of the wealth. A small proportion of police

officers produce most of the arrests.

This phenomenon is commonly called the 80-20 rule,

where in theory 20 percent of some things are responsible

for 80 percent of the outcomes. In practice, it is seldom

exactly 80-20, but it is always a small percentage of

something or some group involved in a large percentage

of some result. The table shows this rule in practice. It

reports an analysis made by Stacy Belledin of construction

site thefts and burglaries for 55 homebuilders in

Jacksonville, Florida. Eleven of the builders (20 percent of

the group) experienced between them 85 percent of all

the thefts and burglaries at construction sites reported to

the Jacksonville Sheriff’s Department during JanuarySeptember 2004.

In investigating any problem, you should therefore always

ask if the 80-20 rule applies. A simple six-stage procedure

shows how to answer this:

1. Make a list of the people, places, or products, with a

count of the number of events associated with each

of these.

2. Rank order them according to the number of events

associated with each - most to least.

3. Calculate the percentages of the events each person,

place, or product contributes. In the table, there are

386 incidents of theft and burglary. Sixty of these

incidents (15.5 percent) occurred at construction sites

owned by Builder 1.

4. Cumulate the percentages of incidents starting with

the most involved person, place or product (or in this

example, home builders).

5. Cumulate the percentages of the people, places, or

products (in our example, the cumulative percentage

of home builders in column 5).

6. Compare the cumulative percentages of people,

places, or products (column 5) to the cumulative

percentage of outcomes (column 4). This shows how

much the most involved people or places contribute

to the problem.

These kinds of calculations can be very helpful at the

scanning stage in directing preventive effort. Thus, in the

Jacksonville example, just five builders experienced more

than 50 percent of the incidents. In theory, focusing

preventive action on these five builders, rather than on

the total group of 55, could be a very efficient strategy for

reducing the city's overall problem of theft and burglaries

in construction sites.

At the analysis stage, these kinds of tables can help in

determining if there are important differences among

people, places, or products at the top and those at the

bottom of the list. In our example, Stacy Belledin found

that an approximate measure of the numbers of homes

built correlated fairly well with the numbers of thefts and

burglaries experienced by each builder, but it did not

explain all the differences in risk. Other possibly important

sources of these differences could be the neighborhoods

where builders were operating, their police reporting

practices and their standard security precautions.

1818. Learn if the 80-20 rule applies
1

Home Builder

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

3 Builders, 4 Incidents

3 Builders, 3 Incidents

1 Builders, 2 Incidents

9 Builders, 1 Incident

24 Builders, 0 Incidents

55 builders

2

Incidents

60

39

38

34

34

31

29

26

19

11

8

7

7

6

5

12

9

2

9

0

386

3

Percentage Of

Incidents

15.5%

10.1%

9.8%

8.8%

8.8%

8.0%

7.5%

6.7%

4.9%

2.9%

2.1%

1.8%

1.8%

1.6%

1.3%

3.0%

2.4%

0.5%

2.3%

0.0%

100%

4

Cumulative

Percentage Of

Incidents

15.5%

25.7%

35.5%

44.3%

53.1%

61.1%

68.7%

75.4%

80.3%

83.2%

85.2%

87.1%

88.9%

90.4%

91.7%

94.8%

97.2%

97.7%

100.0

100.0

100%

5

Cumulative

Percentage Of

Builders 

1.8%

3.6%

5.5%

7.3%

9.1%

10.9%

12.7%

14.6%

16.4%

18.2%

20.0%

21.8%

23.7%

25.5%

27.3%

32.7%

38.2%

40.0%

56.4%

100.00

100%

Crime Analysis for Problem Solvers in 60 Small Steps

SCAN FOR CRIME PROBLEMS

Reported Thefts and Burglaries at Construction Sites

55 Home Builders, Jacksonville, FL , Jan. - Sept 2004
Other police agencies might already have dealt with

the problem you are tackling or researchers might

have studied it. You could save a lot of time by

finding out how they analyzed it and what they did, in

particular which responses seemed to be effective and

which not. Studying the efforts of others can provide you

with useful hypotheses to test on your problem (Step 20).

Begin with the Problem-Oriented Guides for Police (POP

Guides) available online at www.cops.usdoj.gov and

www.popcenter.org. Each guide summarizes the research

on a particular problem and discusses ways of responding

to it. (The website versions of the guides include links to

source materials that are not available with the print

versions.) New guides are continually being produced, but

if there is not one on your problem, look for related

guides. For example, there is presently no guide on drug

dealing in public housing, which might be the problem

you are tackling. However, guides are available on "Drug

dealing in privately-owned apartment complexes" and

"Open-air drug markets," and reading them could 

be helpful.

Useful Websites

To expand your search, visit the websites listed below.

Don't be tempted to skip those from Australia and the

U.K. because problem-oriented policing is widely practiced

in those countries and the crime problems are similar to

those here. In fact, crime in San Francisco may be more

like that in Sydney, Australia, than in a small town in

Louisiana or Tennessee.

• Center for Problem-Oriented Policing

(www.popcenter.org). Apart from the POP Guides, the

website also contains hundreds of reports of problemoriented projects submitted over the years for the

Goldstein and Tilley Awards. The website's search engine

allows you search these projects by topic and you can

read and download them.

• NCJRS Abstracts Database

(http://abstractsdb.ncjrs.gov). Only a small proportion of

the abstracts on this huge database deal directly with

policing, but it might contain material useful to you.

Abstracts are sometimes linked to the full text of the

article or report, which you can download. In other

cases, you can ask to borrow a copy. This service is free

and efficient - it generally takes no more than 2 to three

weeks to receive the material.

• The Home Office, United Kingdom

(www.homeoffice.gov.uk). The Home Office, roughly

equivalent to the U.S. Department of Justice, undertakes

and sponsors excellent research on police topics. Start

with a "quick search" using the search box on the

home page. A summary is given for each entry. Clicking

on this will take you to the full text.

• Crime Reduction Website, Home Office

(www.crimereduction.gov.uk). Browse the "toolkits"

and "mini-sites," which provide practical guidance in

dealing with many crimes including robbery, residential

burglary, domestic violence, street crime, and

victimization of college students.

• Australian Institute of Criminology

(www.aic.government.au). Begin searching this website

from the opening page. A short description is provided

of each entry yielded by the search. You can get a fuller

description by clicking on the title. Full text downloads

are available of many of the documents.

Other Useful Resources

• Google. If the websites yield little of value, try

"googling" the problem. Google is considered the

premier search tool on the Internet. To enter a query,

just type in a few descriptive words and click on the

search button for a list of relevant web pages. These are

listed in order of importance as calculated by the

number of links to the site. Narrowing your search is as

simple as adding more words to the search terms that

you have already entered. Your new query will return a

smaller subset of the pages found for your original "toobroad" query.

• Other police departments. If you find that other

police departments have tackled the same problem as

yours, try calling them. Try to speak to the crime analysts

or officers originally involved in the project. Unless a

report is available, do not rely too heavily on what you

are told because memory is notoriously unreliable.

• Local faculty. Particularly when your local college has a

criminal justice program, you might obtain useful advice

from a faculty member. Learn about faculty interests

from the college website before attempting to contact

anyone. For anything more than an hour or so of

consultation, the faculty member might expect

compensation, although some state universities consider

assistance to government agencies as part of their

faculty's regular service mission.

1919. Research your problem 
Summarize the responses you identify by constructing a table like that found in the POP

Guides, with one row for each response and five columns as below:

Crime Analysis for Problem Solvers in 60 Small Steps

• National experts. If you repeatedly see an expert's

name during your search, try e-mailing that person for

advice. Ask only for specific information that the expert

can provide quickly. When asking for references, list

those that you have already found, which will let the

expert see whether you have missed 

anything important.

• Interlibrary Loan. Most large public libraries and

college libraries subscribe to this service, which allows

them to obtain books and articles that you might need

from other libraries. You must complete a form that the

library will supply, and expect to wait about 2 weeks for

the material to arrive.

• Criminal Justice Abstracts (CJA). Online access to

CJA is a vital resource that you will usually find only at

colleges with a criminal justice program. Try to persuade

your department to subscribe to it. It covers the major

journals, books and reports in the field. It provides

greater coverage of the academic literature than NCJRS

Abstracts, though the latter provides more coverage of

government research and professional magazines.

Limitations of the Information

Your best sources of information are likely to be (1)

articles by researchers who have studied the problem you

are facing and, (2) reports of police projects dealing with

the problem. However, both have their limitations,

as follows:

• Most criminologists are more interested in crime and

delinquency in general than in specific forms of crime.

They are also more interested in distant causes of crime,

such as social disadvantage and dysfunctional families,

than the near causes of a problem, such as poor security

or lack of surveillance. So even when you find academic

articles dealing with your problem, you might find the

causes they identify help little in developing an

effective response.

• Unless your problem is very common, do not expect to

find many relevant police projects. Be skeptical about

claims of success unless supported by evaluative data.

Even projects that have received Goldstein or Tilley

awards may not have been well evaluated. Be warned

also that a response that worked in a particular town or

neighborhood might not work in yours because of

specific circumstances that make your situation different.

However, past police experience of dealing with the

problem is always an important source of ideas about

what might be helpful in your situation.

If you need more detailed information for a response (for

example, CCTV surveillance), returning to your computer

and the library again should let you find the facts you

need and enable you to profit from the experience

of others.

Read More:

Clarke, Ronald and Phyllis Schultze (2004). Researching a

Problem. Problem-Oriented Guides for Police, ProblemSolving Tool Series No. 2. Washington, DC: Office of

Community Oriented Policing Services. (accessible at

www.popcenter.org and www.cops.usdoj.gov).

ANALYZE IN DEPTH

Most academic articles begin with a short Abstract. If

this looks interesting, read the Summary, Discussion

and/or Conclusions. If these also seem useful, scan the

literature review at the beginning of the article. You can

usually skip the methods sections dealing with data,

analysis, and results. Even if the article is not directly

relevant, you might still find useful material listed in the

References.

Scanning Academic Articles

Identifying responses

1

2

Response Source How It Works Works Best If... Considerations
Whenever we confront some new and perplexing

crime pattern we form hypotheses about its

causes, often based on incomplete information.

Experience and theory are good sources of hypotheses.

You should (1) clearly state your hypotheses, (2) not be

wedded to them, and (3) use data to objectively test

them. Expect all hypotheses to be altered or discarded

once relevant data have been examined because no

hypothesis is completely right. For this reason it is often

best to test multiple conflicting hypotheses.

A set of hypotheses is a roadmap for analysis. Hypotheses

suggest types of data to collect, how this data should be

analyzed, and how to interpret analysis results. If you

were investigating drinking-related assaults in bars you

might begin with the question, "How many bars are

problem locations?" Based on the 80-20 rule (Step 18),

you would state the hypothesis that some bars will have

many fights, but most will have few or none. You would

then test this hypothesis by listing the licensed drinking

places and counting the number of assault reports at each

over the last 12 months.

If your hypothesis was supported, you might ask the

question, "What is different about the bars with many

fights compared to the bars with few assaults?" The

concept of risky facilities (Step 28) would help you form a

set of three hypotheses:

1. Risky bars have more customers.

2. Risky bars have features that attract assaulters.

3. Bar staff in risky bars either fail to control behaviors, or 

provoke fights.

You can test these hypotheses by gathering data on the

number of customers at high- and low-risk bars, analyzing

the number and rate of assaults per customer, observing

the interactions of people at troublesome and trouble-free

bars, and interviewing staff and customers.

If your first hypothesis was contradicted by the data, and

you found that there was no great difference in numbers

of assaults across drinking establishments, then you might

ask the question, why are so many bars troublesome?

This suggests another hypothesis: It's a perception

problem; the city has about as many bar assaults as other

comparable cities. This hypothesis suggests that you will

need data from comparable cities.

If, after you collected the relevant data, you found that

your city has an abnormally high number of problem bars,

you might ask the question, "What is common to most

bars in the city that produces a large number of

assaults?" One hypothesis is that it is the way liquor

licenses are dispensed and bars regulated. Another

hypothesis is that there is something about the nature of

bar customers in your city. Testing each would require you

to collect relevant data and assess the validity of 

the hypothesis.

Notice how the questions and hypotheses structure the

analysis. Test results - positive or negative - reveal new,

more specific questions. The objective is to start with

broad questions and hypotheses and, through a pruning

process, come to a set of highly focused questions that

point to possible responses.

Hypotheses suggest the type of data to collect. In the bar

assaults example, the test of each hypothesis requires

specific data. Sometimes the same data can test multiple

hypotheses (as is the case with choosing among the three

alternative explanations for risky bars). Often a variety of

data is required to select among alternative hypotheses

(as is the case with the last set of hypotheses). The more

specific your hypotheses, the more focused your data

collection will be. This is why it is more important to have

a clear hypothesis you personally dislike, than an unclear

hypothesis you approve of, or worse, no hypothesis at all.

Hypotheses can help direct the analysis of data. Every

clear hypothesis suggests a pattern of data that you

should be able to observe, if the hypothesis is correct. In

the example above, the hypotheses derived from the

concept of risky facilities can be tested using a simple

analytical procedure. If a bar is a crime generator, then

you should see a high number of assaults, a high number

of customers, but a low assault rate (see Step 17). Failure

to find this pattern suggests the hypothesis is wrong. So

it is important to have a clear idea of what you should

observe if your hypothesis is correct, and what you should

observe if your hypothesis is wrong (see third column of

the table). If you cannot do this, then this is an indicator

that your hypothesis may be too vague.

2020. Formulate hypotheses

The lack of explicit hypotheses can lead to "paralysis by

analysis," collecting too much data, conducting too

much analysis, and not coming to any useful conclusion.

Paralysis by Analysis
Crime Analysis for Problem Solvers in 60 Small Steps

Hypotheses help interpret the analysis results. Let's

assume that the analysis of bar fights showed that a few

bars had most fights, and observations of the high- and

low-risk bars indicated that the security staff of the risky

bars provoked fights. This immediately suggests a

possible avenue for intervention. In short, the validity of a

hypothesis must make a difference. That is, if the

hypothesis is true you will take a different decision than if

it is false. If you will make the same decision regardless of

the test results, then the hypothesis and its test 

are irrelevant.

In summary, hypotheses are important for guiding

analysis. To formulate hypotheses you need to ask

important questions, then create simple and direct

speculative answers to these questions. These answers are

your hypotheses. These speculations must be bold enough

that they could be wrong, and there must be a way of

showing whether they are right or wrong. If possible,

create competing hypotheses.

Hypothesis formation is a useful group exercise, as it

allows participants with contrary views to put their

perspectives on the table in a way that allows clear and

objective tests. In this way, participants contributing

invalid hypotheses make substantial contributions to the

analysis of the problem. If each hypothesis is linked to a

potential solution, the test of these hypotheses

simultaneously directs attention to feasible responses and

rules out ineffective approaches.

ANALYZE IN DEPTH

Question

Why is this place risky?

Why are there more car thefts in the

problem area than in nearby areas?

Why did the theft of copper piping

from new construction suddenly

increase?

Example Hypothesis

It is due to a large number of targets

being available.

Residents park their cars on the

street, unlike residents of other

areas.

A new owner bought a nearby scrap

metal dealership.

Possible Test

Count the targets at the location and

calculate the crime rate. Compare

this rate to rates for the surrounding

area. If the risky place has a higher

rate, the hypothesis is false, if it is

about the same or lower, then the

hypothesis is true.

If the problem area has similar or

lower on-street parking rates than

the others, reject the hypothesis. If

higher, accept it.

Compare the thefts of piping before

and after the change in owners. If

the theft rate is the same before and

after, or the trend in thefts was

already going up before the change,

then the hypothesis is probably false.

If otherwise, the hypothesis appears

reasonable.

Questions, Hypotheses, and Tests
I

n the course of your routine analytic work, you

probably use mainly crime incident and arrest data, but

for problem-oriented projects, you will need to use a

much wider array of data. For example, calls-for-service

data could give you a better handle on the amount of

drug dealing at troublesome locations than arrest data.

And data kept by the city and by businesses could be

helpful in analyzing problems of vandalism or shoplifting,

both of which are poorly measured by police reports. But

for most problem-oriented projects you will find it

necessary to go into the field - to use research

terminology - and gather data yourself. For example, you

and your project team might have to make systematic

observations of the environmental features of crime sites;

you might have to survey victims; and you might have to

interview offenders or persuade officers to do this for you.

The need for your own data collection can arise at any

one of the four stages of SARA as the following 

examples show:

1. Ronald Clarke was involved in a project focused on

vehicle-related thefts in downtown parking lots in

Charlotte, North Carolina. It turned out that the city did

not have up-to-date maps showing the location of every

parking lot because new lots were continually being

opened on the sites of demolished buildings and new

buildings were being erected on the sites of former lots.

Consequently, police officers working on the project had

to survey the entire downtown area to make a complete

inventory of lots. Later in the project, officers counted

the spaces in each lot so that the risks of theft per

parking slot could be calculated. This enabled the lots to

be ranked for their risks of theft, from highest to lowest.

Then, in order to explain these variations in risk, officers

collected detailed information about the security of each

lot, including the adequacy of its lighting and fencing

and the use of attendants or security patrols.

2. In another Charlotte project focused on thefts from

construction sites, two police officers working on the

project, Dan Cunius and Eric Rost, regularly checked

each house in the project to make sure that builders

were implementing the agreed preventive measures. By

the time that the study was completed, the officers had

completed a total of 8,050 separate checks on

individual houses - a truly enormous data-gathering

exercise conducted in all kinds of weather.

3. In a report for the National Law Enforcement &

Corrections Technology Center, Karin Schmerler, a public

safety analyst in Chula Vista, Calirfornia, has collected

some other examples of primary data collection in

projects submitted for the Goldstein Award for

Excellence in Problem-Oriented Policing, including 

the following:

•For a project that reduced prostitution-related calls for

service in Buffalo, New York, the police conducted 15 indepth interviews with prostitutes and 116 surveys of

"johns". The information obtained was used to garner

community support for increased enforcement against

johns and increased drug treatment and court options

for prostitutes.

• In the course of a California Highway Patrol project that

reduced deaths by 35 percent on a deadly stretch of

rural roads, a 30-member task force spent 5 hours by

bus inspecting 20 miles of roadway. A key

recommendation made by the task force was to adopt a

24-hour "headlights on" policy.

• In a project to reduce school bullying in South Euclid,

Ohio, police conducted focus group interviews with

students to determine where and when they felt unsafe.

The students identified hallways and class change-overs

as being high-risk times and places for bullying, which

the police confirmed by looking at school incident

records. Based on these findings, class change-over

times were staggered and teachers worked in teams to

increase supervision of hallways. This led to a 60 percent

drop of bullying in hallways.

In her article, Karin Schmerler points out that even ad hoc

data collection can be useful - she gives the example of a

quick visit to a frequently targeted ATM to inspect the

location and the lighting. In other cases, data collection

might require the help of a local university in designing

and conducting the exercise.

2121. Collect your own data

Problem-oriented policing makes many demands on

you, but it does not require you to expose yourself to

the risk of mugging or assault.

Be Careful in Collecting Your Own Data
Matt White and Charles Dean, working in the Charlotte-Mecklenburg Police Department, became convinced that

many offenders were using forged temporary tags on their vehicles. These tags allowed them to operate untaxed,

uninsured vehicles for months or even years, and made it safer for them to use their cars in committing other crimes.

To build a case for reform of the temporary tag system, White and Dean undertook an evening's informal survey of

two same-sized, contiguous neighborhoods in Charlotte - one high crime and the other low. The high crime area

(Belmont on the left in the map) had 6.4 times as many reported violent offenses in the 12 months prior to the

survey and 5.6 times as many resident arrests as the low crime area (Plaza-Millwood). As expected they spotted 12

cars (black dots on map) with temporary tags in Belmont and none in Plaza Millwood. This was despite similar onstreet parking in both neighborhoods and a higher proportion of cars in Belmont backed into driveways to hide their

tags from passing patrols.

Crime Analysis for Problem Solvers in 60 Small Steps

While you might resist collecting your own data because

of the difficulties and time involved, it is sometimes

essential for a problem-oriented project and it always

brings benefits, as follows:

1. Getting into the field can give you an understanding of

the problem that you would never get from sitting in front

of your computer, however rich the data that you

manipulate.

2. Designing a data-collection instrument can force you to

think very hard about the nature of the problem, about

the kind of responses that might be effective, and how

best to evaluate your efforts.

3. Involving police officers in data collection (and in the

design of the exercise) provides a valuable opportunity to

train them in the need for a rigorous, systematic approach

in a problem-oriented project.

4. Undertaking your own data collection gives you the

opportunity to hone your research skills and be 

genuinely creative.

Read More:

Schmerler, Karin and Mary Velasco (2002). "Primary Data

Collection: A Problem-Solving Necessity". Advanced Crime

Mapping Topics. Denver, CO: National Law Enforcement &

Corrections Technology Center, University of Denver.

ANALYZE IN DEPTH

Tabulating Temporary Tags

Source: White, Matt and Charles Dean (2004). "Abuse of Temporary License Tags in North Carolina". Understanding

and Preventing Car Theft, Crime Prevention Studies, Volume 17, edited by Michael Maxfield and Ronald Clarke,

Monsey, NY: Criminal Justice Press.
FREQUENCY DISTRIBUTION OF HOMICIDES IN CINCINNATI NEIGHBORHOODS

Number of Neighborhoods

Number of Homicides

A

fter collecting your data you need to know what it

is telling you. Suppose you collected incidents of

assaults on taxi drivers. Are assaults concentrated

among a very few drivers? Are the assaults concentrated

on some days of the week or times of day? 

To answer these questions you need to look at the

distribution of the data. The figure below displays the

distribution of homicides across Cincinnati's 53

neighborhoods for a 36-month period. The horizontal axis

shows the number of homicides in a neighborhood. The

vertical axis shows how many neighborhoods had each of

these numbers (so in the first column, 13 neighborhoods

had zero homicides). Most neighborhoods had few

homicides but there is a long tail stretching to the right

where a few neighborhoods have many homicides.

Often you need to summarize a distribution. There are

two basic descriptions of distributions: the typical, or

average, case and the variation, or spread of cases.

The Average Case. The average can be calculated 

three ways:

• Mean. This is the most common measure of

average. The mean number of homicides in the

Cincinnati neighborhoods is 3.7 homicides per

neighborhood - calculated by dividing the 198 killings

by the 53 neighborhoods.

• Median. This is the value that divides the cases into

two equal groups. Half the Cincinnati neighborhoods

have two or more homicides and half have two or

fewer.

• Mode. This is the value possessed by the greatest

number of cases. In this example the mode is 0

homicides because the biggest group of

neighborhoods have no homicides.

The Spread of Cases. There are three common

methods to measure spread:

• Range. This is most basic measure of spread. This is

the lowest and highest value. In our example, the

range is 0 to 27 homicides.

• Inner quartile range looks at the lower and upper

bounds of the middle 50 percent of the cases. In the

Cincinnati example, the inner quartile range is one to

five homicides. Half the neighborhoods fall into this

bracket. Another 25 percent of the neighborhoods

have one or no homicides and the last 25 percent

have 5 or more homicides. To find the inner quartile

range, rank the cases and divide them into four equal

groups. The two middle groups are the innerquartiles. The inner quartile range is the lowest and

the highest value of these two middle groups.

• Standard deviation. This measure of spread

indicates the mean difference from the mean of the

distribution. The smaller the standard deviation, the

smaller the average spread around the mean. The

formula is rather tedious, but any spreadsheet or

statistical software package can calculate it. Two

thirds of the cases fall within one standard deviation

on both sides of the mean. In the Cincinnati

example, the standard deviation is 5.2 homicides.

2222. Examine your data distributions

14

12

10

8

6

4

2

0

0 1 2 3 4 5 6 7 8 9 10 14 22 27

Range 0 to 27 homicides

Mode=0 homicides

Inner quartile 1 to 5 homicides

Median=2 homicides

Mean=3.7 homicides

66.7% of neighborhoods within one std. deviation of mean (std. dev.=5.2)
Crime Analysis for Problem Solvers in 60 Small Steps

Which measures of typicality and spread are best depends

on two characteristics of the data. The first is the

symmetry of the distribution. In a symmetrical distribution,

the shape on one side of the mean is mirrored on the

other side. The mean equals the median in symmetrical

distributions. If the value with the most cases is in the

center, then the mode will be the same as the other two

measures of average. But the mode need not equal the

median or the mean. The distribution could have two

modes, one on each side of the median. If the distribution

is roughly symmetrical, the mean and standard deviation

may be appropriate.

If the distribution is asymmetrical, then the mean and

standard deviation should not be used. Use the median

or the mode and the inner quartile or full range. In

problem analysis, asymmetry is very common.

The second characteristic used to select measures of

typicality and spread is the measurement scale used for

the data. There are three common types of scales.

• Nominal scales simply apply labels. Gender

(male=1, female=2) is measured with a nominal scale

because the numbers simply substitute for word

labels, and the categories could be relabeled, male=2,

female=1 without creating a problem. If your data is

nominal, then only a mode is appropriate.

• Ordinal scales rank cases as well as label them. An

ordered list of neighborhoods, from greatest to fewest

homicides produces an ordinal scale (first, second,

third, through fifty-third). You cannot add and

subtract, multiply and divide ordinal data. You can

only determine if a case has a greater, lesser or equal

rank to another case. If the data is ordinal, neither

the mean nor the standard deviation can be used.

Use the median and inner quartile range.

• Ratio scales allow you to add, subtract, multiply and

divide because the difference between each value is

equal and there is a meaningful zero. The number of

homicides in a neighborhood is measured with a ratio

scale: the difference between 0 homicides and 1

homicide is the same as the difference between 26

homicides and 27 homicides, and 0 homicides has

meaning. You can use a mean and standard

deviation with this type of data.

Read More:

Help for elementary to advanced statistics with many

useful links

www.prndata.com/statistics_sites.htm - Hyperstat

HyperStat Online Textbook

http://davidmlane.com/hyperstat/index.html

ANALYZE IN DEPTH

TYPES OF DATA, THEIR USE, AND THEIR LIMITATIONS

Description

Example

Allowable Math

Allowable Average

Allowable Spread

Comments 

Nominal

Names categories

0= not victim

1= victim 

is as valid as

0= victim

1= not victim

Same or not same

Mode

Range

Used when dealing with

categories (e.g., gender)

and groups (e.g. chain

stores, not chain stores).

Ordinal

Ranks & names categories

0= no crime

1= one crime

2= more than one crime

Ratio

Has equal intervals between numbers, and zero is

meaningful.

Number of crimes: 0, 1, 2, ...

(0= no crimes)

Scales to the right have all the properties of those to their left, plus their own properties (e.g., anything you can do with nominal and

ordinal data you can do with ratio data, plus more).

Greater, lesser, or equal

Median & Mode

Inner quartile range & Range

Use when there is a natural

ranking or order to categories

(e.g., police ranks) but the

differences between ranks is not

always the same or unclear.

Addition, subtraction, multiplication, & division

Mean, Median, & Mode

Standard deviation & others

Use for percents, counts, and a host of other

measures.
When mapping crime, it is helpful to distinguish

between acute and chronic hot spots (Step 17).

Acute hot spots show abnormal spikes in crime,

which may decline naturally, while chronic hot spots have

persistently higher crime levels than other areas and are

unlikely to decline unless something is done. There are

three basic forms of chronic hot spots, each of them

linked to particular theories and types of responses.

• Hot dots are locations with high crime levels. These

show crime concentrated at facilities or at addresses of

repeat victims (see Steps 28 and 29). Multiple crime

events at places are represented by dots.

• Hot lines are street segments where crime is

concentrated. These might occur, for example, if vehicles

parked along particular streets suffer high rates of

break-ins. Multiple crimes along street segments are

shown with lines.

• Hot areas are neighborhoods where crime is

concentrated. Hot areas arise for a variety or reasons.

Area characteristics may give rise to crime. Or a hot area

may contain many separate and discrete problems. On

maps, hot areas are shown as shaded areas, contour

lines, or gradients depicting crime levels. Jerry Ratcliffe’s

hot spot typology (see box) differentiates between two

kinds of area hot spots:

• those that have a tightly grouped pattern of 

events and

• those that have a relatively even spread of events over

the hot spot area.

The figure depicts these three forms of hot spots.

Troublesome entertainment locations are shown as dots

because the assaults are located at addresses. Vehicle

break-ins, however, are along continuous street segments,

so this concentration is shown as two intersecting lines.

Finally, the graduated contours for the residential hot spot

suggests that risk for break-ins is highest in one small

area but declines as one goes away from the center. The

dots within this graduated area depict repeat 

burglary locations.

Clarifying the nature of your hot spot gives an inkling 

of response:

• Hot dots suggest changing the physical environment of

particular places or changing their management. They

also suggest intervening with high-risk victims.

• Hot lines suggest changing streets, paths and other

routes, or the environments along them.

• Hot areas suggest large-scale partnerships to change

neighborhoods.

The table shows how crime concentration is related to the

way it is mapped, and where the response is focused.

2323. Diagnose your hot spot

Concentration

Places - at specific

addresses, corners, or

facilities

Victims

Streets - along streets or

block faces

Area - neighborhoods

Hot spots shown as:

Dots

Dots

Lines

Shaded areas

Action level

Facility, corner, address

Victims' addresses

Along paths, streets, and

highways

Neighborhoods, regions and

other areas

Action examples

Closed circuit television in a

parking garage, changing

the way alcohol is served in

bars.

Helping victims prevent

further crimes through

target hardening.

Creating cul-de-sacs,

changing traffic patterns,

altering parking regulations.

Community partnerships,

neighborhood

redevelopment.

Concentration, Mapping and Action
Crime Analysis for Problem Solvers in 60 Small Steps

Analysis of hot spots should begin with places, then move

to streets, and finally to areas. Consider, for example, the

problem of burned-out cars. Are they repeatedly found at

specific addresses? If yes, then you should ask why these

places are chosen instead of other nearby sites. If no, you

should move on to examine streets. If you find street-level

concentration, you should compare streets to find out why

some attract burned-out cars and others do not. If there is

little street-level concentration (i.e., crime is spread

relatively evenly across many streets), then you should

consider community concentration and compare high- and

low-concentration neighborhoods. This approach assures a

highly focused response.

In the figure, the hot burglary dots indicate repeat victims

within the overall neighborhood problem. An area hot

spot alone would not reveal this. Before proceeding

further, you should determine if the area hot spot is

largely due to the few repeat burglary spots. You can do

this by treating each crime location as if it had only a

single event, and then look at the area. If it is no longer

hot, then the problem is driven by a few hot places. If the

area is still hot, then these repeat burglary dots are

fragments of an area concentration of burglaries.

Hot spot analysis can be a valuable tool early in the

problem-solving process, but having discovered hot spots,

you need to ask why some spots are hot and others are

not. Stopping analysis after the discovery of hot spots

can result in superficial analysis and the implementation

of ineffective responses. If there is no geographical

component to the problem, hot spot mapping has little

utility and you must use other analytical approaches.

Read More:

Eck, John, Spencer Chainey, and John Cameron (2005).

Mapping Crime: Understanding Hot Spots. Washington,

DC: U.S. Department of Justice, National Institute 

of Justice.

ANALYZE IN DEPTH

Jerry Ratcliffe differentiates among three types of hot spots. He begins with a hot spot area and then examines the

point pattern. If all events occur at the same location then the hot spot is a "hot point." Hot points describe the

same phenomena as hot dots. If the events are tightly grouped within the overall area, Ratcliffe calls this a

"clustered" hot spot. Finally, if the events are spread relatively evenly across the hot spot area, he calls the hot spot

"dispersed." Clustered and dispersed hot spots are subcategories of our category of "hot area." Ratcliffe's

approach draws attention to the concentration of the events and requires the analyst to define the perimeter of the

hot spot area prior to classifying the hot spot.

Ratcliffe's Hot Spot Typology

Source: Ratcliffe, Jerry (2004). "The Hotspot Matrix: A Framework for the Spatio-Temporal Targeting of Crime

Reduction". Police Practice and Research 5:5-23.

Types of Hotspots

Hot lines representing

thefts from vehicles along

a side street parallel to

an arterial route

One of four hot dots representing

entertainment venues with a

high numbers of assaults

One of five hot dots

showing repeat

burglary locations

A hot area represented

as a gradient of risk for

residential burglary
C

onventional software is of little use when mapping

crime in a downtown area, a college campus, a

public housing project, or any site with many large

buildings. This is because most buildings, however large,

have only one street address, and crimes occurring

anywhere in the building are assigned to that address.

Mapping might therefore suggest that a particular

building or facility has a crime problem, but this may only

be because it is so large. When account is taken of the

many people working in the building or using the facility,

it could prove to be relatively safe. For example, George

Rengert showed that a parking garage in central

Philadelphia identified as an auto crime hot spot actually

had a lower rate of auto crime than the surrounding

streets, once account was taken of the large number of

cars that could be parked in the facility.

In fact, many large buildings are not safe. In his

devastating critique of 1960s American public housing,

Oscar Newman showed that the taller a tower block, the

higher the rate of crime per 100 residents. He argued that

very large blocks invited crime because residents did not

know their neighbors and the design and layout of the

buildings made it difficult for them to exercise any

supervision of the public spaces, including corridors,

elevators, and play areas. His ideas have since been

developed into a set of principles - Crime Prevention

through Environmental Design (CPTED) - for designing

and laying out secure buildings and public spaces.

To understand why a particular building is insecure, crimes

need to be divided into specific categories and their

locations within the building need to be charted. This is

where high-definition or 3-D mapping comes into play.

Unfortunately, high-definition mapping is difficult and time

consuming. It suffers from two principal problems:

1. Police records of crime rarely give the precise location

of incidents within the building, though building

managers or security departments can sometimes supply

this information. When they cannot, special crimerecording procedures may have to be established for a

period of time in order to obtain this information 

(Step 21).

2. For new buildings, it may be possible to obtain plans in

digitized format, which can make mapping easier. But

when the building is old, it may be difficult to obtain upto-date plans so you may have to get these drawn.

In many cases, these problems will simply rule out highdefinition mapping, but they can be overcome, as George

Rengert and his colleagues showed in their study of crime

on Temple University's campus in Philadelphia. They

developed a high-definition GIS by combining mapping

software with AutoCAD drawings of the campus. Features

such as water pipes and electrical wiring were eliminated,

and the maps were altered so that streets were

represented as lines (with lines on either side representing

pavements), while polygons were used to represent the

footprints of buildings and the shapes of athletic fields

and parking lots. Shrubbery, fences, lighting, and other

physical features were also represented on the maps.

Crimes recorded by the campus police were then plotted

exactly where they occurred, allowing them to be related

to environmental features such as poor lighting or a blind

corner allowing the attacker to lie in wait.

Crime was mapped for the floors of each building and a

picture of the horizontal arrangement of crime within the

building was projected onto its ground floor footprint.

Figure 1 shows the result for one of the buildings -

Gladfelter Hall. Crime is distributed among all floors, with

the exception of the 10th floor. The map also shows a

clear cluster of crime common to most floors, the area

closest to the bank of four elevators near the center of the

building. This is where each academic department's

fishbowl offices for secretaries and receptionists are

located - fishbowls because they are surrounded by glass

windows, which allow thieves to look into them to see if

anyone is there and if anything is worth taking. The

Department of Criminal Justice - Rengert's own

department - has now installed blinds, which can be

lowered in the evenings to prevent people seeing into 

the fishbowl.

Commercial software is already available that will produce

photo-realistic city models, and technological

developments, such as 3-D laser imaging, will simplify the

production of computer maps like those of Gladfelter Hall.

Meanwhile, when the number of incidents is small, good

clear drawings with the location of crimes clearly indicated

can sometimes do just as well. Figure 2 is a plan of the

Lisson Green public housing estate in London, drawn by

Barry Poyner, showing the locations of robberies and purse

snatches on the walkways connecting the buildings for

two 6-month periods: before any preventive changes were

made and after four of the blocks were fitted with entry

2424. Know when to use high-definition maps
Crime Analysis for Problem Solvers in 60 Small Steps

phones. In effect, the entry phones closed access to the

walkway system from the main street entrance. In this

case, high-definition mapping assisted with the

assessment of preventive action. But Figure 2 also helped

with diagnosis of the problem because it showed that

robberies and purse snatches tended to occur on those

parts of the walkway system that lacked surveillance from

neighboring buildings or ground level.

Read More:

Crowe, Tim (1991). Crime Prevention Through

Environmental Design. Applications of Architectural Design

and Space Management Concepts. Boston:

Butterworth-Heinemann.

Rengert, George, Mark Mattson, and Kristin Henderson

(2001). Campus Security. Situational Crime Prevention in

High-Density Environments. Monsey, NY: Criminal 

Justice Press.

ANALYZE IN DEPTH

Figure 1: 3-D Map of Gladfelter Hall, Temple University Campus

High Definition

Geographic

Information

System

Crime Projected 

on Building Footprint

Crime on Building Floors

Figure 2: Locations of Robberies and Snatches on the Walkway System on the Lisson Green Estate

Key

Housing blocks

Blocks fitted

with entry

phones

Walkways

Robbery or

snatch

Elevator and

stair towers

Before Entry Phones After Entry Phones
C

ycles of activities have tremendous influences on

problems. The ebb and flow of vehicles caused by

commuting and shopping rhythms, for example,

changes the number of targets and guardians in parking

facilities. This, in turn, influences when vehicle thefts and

break-ins are most frequent. Robberies of drunken

revelers may be more likely around bar closing time on

Fridays and Saturdays, because the number of targets is

higher. In this example, two important rhythms

concentrate problem activities. The first is the

workday/weekend cycle that makes Friday and Saturday

nights so popular for entertainment and recreation. The

second involves the daily cycle of opening and closing of

bars. In this step we will discuss short-term fluctuations

occurring over hours and days. In Step 26, we will look at

longer time periods covering months and years.

Different facilities have different cycles of activities that

can contribute to their associated problems. School

rhythms are similar though distinct from job rhythms. Bus

stops are influenced by the rhythm of commuting and

shopping, but also by the more frequent coming and

going of buses.

Charting the rhythm of crime or disorder events helps

identify important activity cycles that may contribute to a

problem. As shown in the figure below, calculate the

average of the number of events occurring in each hour

(or other time interval) over several days (data matrix at

top), then plot the results (Chart A). Chart B shows the

percentage of the week's events occurring on each day.

Because some days routinely have very different rhythms

than other days, Rachel Boba recommends charting days

and hours together (Chart C). The result shows hot time

periods throughout the week. Such charts are easy to

produce; all three of these charts were created on a

spreadsheet, using standard graphing routines.

Temporal analysis is easiest when problem events are

frequent. So temporal analysis will be more useful for

common minor events, like noise complaints and minor

traffic accidents, than for uncommon serious events, like

murder. If there are few events, then you can look at a

longer period to collect more events. But if the problem

changes in the longer period, the picture that emerges

may be distorted or out of date.

Having reasonably exact times of occurrence helps

temporal analysis. Contact crimes, such as robbery, rape,

and assault, can be accurately pin-pointed as victims can

often describe when these crimes took place. Property

crimes, such as vehicle crimes, burglary, and vandalism,

are much harder to pin down because victims usually

provide only a time range during which such crimes could

have occurred. Though it is common to use the midpoints

in these ranges to estimate the times crimes occurred, this

can lead to distortion and should be avoided for long

periods (e.g., more than 8 hours).

Jerry Ratcliffe also has identified three forms of temporal

clustering. First, events may be relatively evenly spread

over the entire day. He calls this a diffused pattern.

Second, focused patterns show clustering within distinct

time ranges. Events clustered around rush hours follow

focused patterns. Third, acute patterns are tightly packed

within small periods. Disturbances immediately following

bar closing time might be an example. Focused and acute

patterns immediately suggest temporal cycles that should

be investigated.

Though Ratcliffe developed his typology for daily patterns,

the basic idea can be applied to weekly cycles. If no

particular day of the week is routinely troublesome, this

indicates a diffused weekly pattern. A cluster of days

showing a marked increase in troublesome events

indicates a focused pattern. Finally, if one or two days

have a marked concentration of events, this indicates an

acute pattern.

Read More:

Boba, Rachel (2005). Crime Analysis and Crime Mapping:

An Introduction. Thousand Oaks, CA: Sage Publications.

2525. Pay attention to daily and weekly rhythms

Days 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Mean

Mon 7 3 6 9 9 11 10 17 16 17 5 6 12 7 9 5 20 18 16 8 7 10 8 7 10.1

Tues 10 9 10 11 7 6 13 15 15 18 6 12 7 7 8 5 16 18 17 12 5 11 10 4 10.5

Wed 4 11 12 6 8 3 18 17 24 14 10 7 4 2 4 9 23 24 24 7 5 12 3 4 10.6

Thur 8 8 7 9 4 10 17 21 20 11 10 5 4 3 9 6 17 24 18 4 5 4 10 6 10.0

Fri 3 12 6 7 9 12 13 19 20 19 3 4 3 4 9 3 15 16 17 8 10 18 12 13 10.6

Sat 10 12 3 1 1 1 1 1 2 3 4 3 4 5 6 4 7 8 7 5 10 21 24 23 6.9

Sun 21 22 10 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 3.1

Mean 9.0 11.0 7.7 6.4 5.6 6.3 10.4 13.0 14.0 11.9 5.6 5.4 5.0 4.1 6.6 4.7 14.1 15.6 14.3 6.4 6.1 11.0 9.7 8.3

Hours

Example of Number of Events by Hour and Day of Week
Crime Analysis for Problem Solvers in 60 Small Steps

ANALYZE IN DEPTH

16

14

12

10

8

6

4

2

0

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

A. Average Hourly Rhythm

Hours

Events

B. Percent of Week's Events

Percent

Mon

Tues

Wed

Thur

Fri

Sat

Sun

C. Daily and Hourly Rhythms

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hours

20-25

15-20

10-15

5-10

0-5

EXAMINING TEMPORAL RHYTHMS

.0 5.0 10.0 15.0

Mon

Tues

Wed

Thur

Fri

Sat

Sun
I

s your problem getting worse or better? Does it

fluctuate regularly or randomly? To answer these

questions you need to study your problem by graphing

either the number of events or a rate against time. A rate

is typically the number of crime or disorder events divided

by the number of targets at risk (Step 27).

The time course of a problem can be divided into three

basic components:

• The overall trend, which may be obvious from visual

inspection, and which shows whether the problem is

getting worse, better, or staying the same over a 

long period.

• Seasonal, daily, and weekly cycles.

• Random fluctuations that are caused by a large

number of minor influences.

Systematic study of the time course of crime is called

"time series analysis."

Figure 1 shows homicides in Buffalo, New York. The

straight line through the middle of the chart shows the

overall trend. It is virtually flat, indicating very little

upward trend (though it is increasing slightly at about 1

homicide per 100 months). May 2001 was a particularly

bad month, and October and November of 2000 were

particularly low months.

Throughout the 58 months there is considerable monthly

variation, shown by the jagged peaks and valleys. Low

frequency problems tend to have this characteristic,

whereas problems with many events per time period often

show smoother changes. These random fluctuations can

hide systematic variation. One method for revealing a

trend obscured by random variation is to use a moving

average. This is called "smoothing". A 3-month moving

average was used in this example. The July value, for

example, is the average of June, July, and August while

the August value is the average of July, August, and

September. Notice that there is no data for the first and

last months of the series because we do not have 3

months of data for these months. Moving averages fill in

the valleys and knock off the peaks. Longer moving

averages produce smoother graphs than shorter ones, but

they can also hide useful information by making the graph

too smooth.

2626. Take account of long-term change

Trend

Smoothed

Homicides

Figure 1: HOMICIDES IN BUFFALO, NY 

Jan. 00 through Oct. 04

20.0

18.0

16.0

14.0

12.0

10.0

8.0

6.0

4.0

2.0

0.0

Jan 00

Apr 00Jul 00Oct 00Jan 01

Apr 01

Jul 01Oct 01

Jan 02

Apr 02Jul 02Oct 02

Jan 03Apr 03Jul 03

Oct 03

Jan 04

Apr 04Jul 04

Oct 04

Number of homicides
Crime Analysis for Problem Solvers in 60 Small Steps

Cycles can be detected by comparing the same months of

the year (or same weeks of the month, or same days of a

week, or same hours of a day, depending on the time

periods you are examining). It is important to note that

months are of different lengths (and do not forget

February in leap years) as this might influence the number

of problem events. Some analysts use 4-week periods,

rather than months, to address this issue.

Obvious seasonal cycles can be seen in Figure 2. Here we

see the number of bicycle thefts per month over 32

months. Thefts consistently peak in July and August, and

consistently reach their minimum in January and February.

We can also see that on a month-to-month basis 2001

was usually worse than 2002 and the months of 2003 for

which we have data. This makes some sense, as there are

more bicycles available to steal in the summer and even

thieves have little use for bicycles in the winter (especially

in Buffalo!).

Separating a time series into component parts is very

useful for revealing possible causes of a problem. The

homicide trend, for example, could be decomposed into

two charts showing domestic homicides and 

non-domestic homicides (or firearm and non-firearm). So

if the non-domestic homicides were trending upward

while domestic homicides were declining, this would

suggest that attention should be focused on 

non-domestic homicides.

Time series analysis is a powerful tool for evaluating the

effectiveness of a response. The basic principle is to obtain

a good idea of a problem's natural trends, cycles, and

variation before the response is implemented, using the

techniques just discussed. This tells you what you can

expect from the problem in the future, if you did nothing

about the problem. This provides a basis for examining

time frames after the response. Changes in the trend,

cycles, or even the random fluctuation suggest the

response had an impact. The longer the time frames

before and after, the greater the confidence you can have

in your conclusions.

Time series analysis can also be very complex, so if there

is a great deal depending on a precise answer to a time

frame analysis, it may be useful to seek the help of a

statistician specializing in this area.

ANALYZE IN DEPTH

Figure 2: SEASONAL EFFECTS IN BUFFALO BICYCLE THEFTS

Jan. 01 through Aug. 03

120

100

80

60

40

20

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

2001

2002

2003

Number of Bicycle Thefts
When one place has more crimes than another

place, one possible reason is that one has more

targets than another. Examining rates helps you

understand if number of targets contributes to your

problem (see Step 17).

Rates describe the number of crimes per target at risk,

during a period of time: one burglary per 1,000

households during 2002, for example. Target rates show

the risk the average target has of being involved in a

crime during the time period.

To calculate target rates you will need to:

1. Define the type of event you are interested in (e.g.,

thefts from vehicles).

2. Define the at-risk population (e.g., vehicles).

3. Define the locations and time period (e.g., downtown 

area parking lots in 2004);

4. Find sources of data that that provide counts of events 

of interest and targets for each location being 

examined (e.g., police reported crime data has 

information on address of theft, which can be 

associated with specific parking lots, and observations 

of downtown parking lots can provide estimates of the 

number of vehicles in each lot).

5. For each location, divide the number of events (the 

numerator) by the number of targets

(the denominator) to obtain rates.

Defining the targets at-risk requires careful thought. If

you are analyzing burglaries, is your target people or

homes? "Homes" is the more reasonable answer.

Everything being equal, if a population of a 1000 people

lived in 500 units we would expect it to have more

burglaries than if the same population lived in 250 units.

If you are analyzing street robberies, then the at-risk

population is the number of pedestrians in the area 

being examined.

Police incident reports usually contain data describing the

events of interest, including address information, so

counts of events at locations can be obtained. However,

it is often difficult to obtain information describing the

number of targets at risk at locations. For example,

reported thefts from vehicles may be available for parking

lot addresses, but the number of vehicles using the lots

may not be readily available (see box).

To overcome this problem, you might have to find proxy

measure of targets. The number of vehicles using parking

lots, for example, may be proportional to lot size. Thus, a

proxy measure for vehicles at risk might be square

footage or number of parking spaces. The table gives

some examples of estimating at-risk target rates.

Proxy measures of targets must have two characteristics.

First, they must be logically associated with the targets.

One would expect spaces to be associated with the

volume of vehicles, but we would not expect number of

feet of parking lot street frontage to be associated with

number of vehicles, because very deep lots could have

little street frontage but contain many vehicles. Second,

the association between the proxy and at-risk targets

cannot vary too greatly across locations. If all parking lots

in the downtown area are about two thirds full during the

week, number of spaces is a useful proxy. But if some

lots are used to capacity and others get little use, then

number of spaces is not a good indicator of targets.

2727. Know how to use rates and denominators

Type

Apartment burglaries

Shoplifting 

Motorcycle Theft

Graffiti

Taxi robberies

Disorder calls from

motels

Example of Rates for Different Crimes

Location

Apartment buildings

Retail stores

Neighborhood

Commercial areas

Company

Motels

Rate

Burglaries per apartment, or per

household

Thefts per item on shelves, or per

square foot of retail space

Motorcycle thefts per registered

motorcycle

Graffiti per square foot

Robberies per cab, or per driver, or

driver-hours

Disorder calls per guest or per

room

Comments

Burglaries per resident places too much emphasis on

large families.

Thefts per customer gives an offending rate.

Problematic for areas cyclists use but do not live in.

Difficult to measure.

Hours of exposure is preferable, but data may not be

available.

Might also look at numbers of non-guest visitors.
Crime Analysis for Problem Solvers in 60 Small Steps

Even with proxy measures, it can be difficult to obtain

target data. Government agencies might have some of

the information you need. For example the Hamilton

County, Ohio, auditor has information on every land

parcel in the county, including the square footage and

location. Businesses and business associations sometimes

have information about sales volume. And state supplied

sales tax information can be used as proxy for the

numbers of customers (when comparing stores selling

similar items).

Calculating rates can be very helpful in finding risky

facilities (Step 28). Karin Schmerler and her colleagues in

the Chula Vista, California, Police Department investigated

calls from the city's motels. The 10 national chain and 16

local independent motels generated similar numbers of

calls, but the national chains contained more rooms.

When they added up all the calls for the local

independents and divided this by the rooms in these

motels, Schmerler found that the average call rate for the

independent motels was 1.8 per room. Doing the same

for the national chains yielded a call rate of 0.5. Clearly,

the local independents generate many more calls 

per room.

Should you put more emphasis on high numbers or high

rates? If your objective is to reduce the volume of crime,

then focusing on numbers may the best choice. But if

your objective is to reduce the chances of harm, then

focus on rate.

ANALYZE IN DEPTH

The value of calculating rates is illustrated by a project

in Charlotte, North Carolina on which one of us

(Clarke) worked with Herman Goldstein. Assisted by

local analysts and police officers, we examined

larcenies from autos (LFAs) in parking facilities in the

downtown area of the city (locally known as Uptown).

Hot spot analysis had shown a large undifferentiated

cluster of these thefts centered in the middle of the

area, but a map based on rates of theft was far more

revealing. This map was produced by crime analyst

Matt White, who enlisted the help of precinct officers

in counting the number of parking spaces in each

facility. He then calculated theft rates for each lot and

parking garage. The resulting map revealed a much

more detailed picture of risk. Further analysis showed

that cars parked in lots were six times more at risk

than ones in garages and that some lots were crime

enablers due to inadequate security.

Read More:

Clarke, Ronald and Herman Goldstein (2003). Thefts from

Cars in Center City Parking Facilities. From Innovation to

Mainstream. Crime Prevention Studies, vol. 15, Monsey,

New York: Criminal Justice Press. (available at:

www.popcenter.org)

Rates of theft from cars by block, Charlotte NC, 1999

Using Rates to Identify Risky Parking Lots

Legend

Uptown Study

Area and Analysis

Parking Areas

1999 LFA by block

Lower

Higher
F

acilities are environments with special functions (Step

15). Educational facilities involve teaching and study.

Industrial facilities produce and process materials.

Office facilities process information. Retail facilities involve

sales and monetary transactions. Some facilities are

frequent sites for crime and incivilities. These include

taverns, parks, railway stations, payphone booths,

convenience stores, and public housing projects. These

facilities make a disproportionately large contribution to

crime and disorder - they are "risky facilities."

But the term has also a more precise meaning. It refers to

the fact that within each type of facility a few of them are

especially risky. When we described the 80-20 rule in Step

18, we mentioned that 5 percent of the stores in Danvers,

Massachusetts, accounted for 50 percent of the reported

shopliftings (see the table provided by Christopher Bruce,

crime analyst in the Danvers Police Department). Here are

some other documented examples of risky facilities:

• Convenience stores. A national survey found that 6.5

percent of convenience stores experience 65 percent of

all robberies.

• Gas Stations. Ten percent of Austin, Texas gas stations

accounted for more than 50 percent of calls for driveoffs and drug crimes in 1998-1999.

• Banks. Four percent of U.K. banks have rates of

robbery four to six times higher than other banks.

• Schools. Eight percent of Stockholm schools suffered

50 percent of the violent crimes reported in the 1993-

1994 school year.

• Bus stops. Andrew Newton's recent doctoral

dissertation reported that 9 percent of the shelters at

bus stops in the British city of Liverpool experienced

more than 40 percent of the vandalism incidents.

• Parking facilities. In another British city, Nottingham,

just one parking deck (The Royal Moat House)

accounted for about 25 percent (103) of the 415 crimes

reported for all 19 downtown lots in 2001.

There are at least eight reasons why facilities are "risky"

and different analysis procedures can help determine

which reasons are operating in particular circumstances:

1. Random Variation. It is possible to get

concentrations of crime in a few places through some

fluke of randomness. This is more likely to occur when

you are looking at only a few facilities with few

incidents. Try checking the same facilities for a different

time period. If the rank order of incidents is roughly the

same in both periods, then the variation is not random.

2. Reporting practices. Some facilities might always

report crimes to the police, while others experiencing

the same number of incidents might report many fewer

of them. This can be difficult to check, but you should

ask officers who are familiar with the facilities whether

the recorded crime rates match their own perceptions of

the crime problems in the facilities.

3. Many targets. Some facilities contain many targets.

The store with the most shopliftings in Danvers was one

of the largest in the city. But this was not the whole

story because when account is taken of its size by

calculating shopliftings per 100 square feet (see the

final row of the table), it is still one of the riskiest for

shoplifting (see Step 27).

4. Hot products. A risky facility may not have a large

number of targets, but it might have targets that are

particularly "hot." Store 15 in the Danvers list had the

highest rate of shoplifting in the city per 1,000 square

feet. This store specializes in selling small, high value

electronic items that meet the CRAVED criteria described

in Step 31.

5. Location. Facilities located in high-crime areas,

perhaps where many habitual offenders live, are more

likely to be crime risks. This is because offenders prefer

not to travel far to commit crime (Step 16).

6. Repeat victimization. Some places attract people

who are particularly vulnerable to crime. Compare the

people being victimized in risky and non-risky facilities.

If the re-victimization rates are different, then repeat

victimization may be the cause of the elevated risk (Step

29).

7. Crime attractors. Facilities that draw in large

numbers of offenders are crime attractors (Step 15).

Crime attractors have high numbers of offenses and

high offense rates. Additional diagnostic checks involve

analysis of arrest records and other information

containing offender names.

8. Poor management. When owners or managers do

not exercise proper control or management a risky

facility can develop. The box shows how a slumlord's

negligent management turned the properties he

acquired into risky facilities (Step 44).

2828. Identify risky facilities
Crime Analysis for Problem Solvers in 60 Small Steps

ANALYZE IN DEPTH

Read More:

Eck, John, Ronald Clarke and Rob Guerette,

"Risky Facilities: Crime Concentration in Homogeneous

Sets of Facilities." Crime Prevention Studies, in press.

Store*

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

7 stores with 2 incidents

28 stores with 1 incident

26 stores with 0 incidents

Total stores = 78 

Reported Shopliftings by Store, Danvers, MA.

October 1, 2003 to September 30, 2004

* The top 17 stores were (in alphabetical order): Best Buy, Boater's World, Circuit City, Costco, CVS Pharmacy, Galyan's, Home Depot,

Kohl's, Linens & Things, Lowe's, Marshall's, Old Navy, Radio Shack, Stop & Shop, Target, and Wal-Mart

Shopliftings

78

42

28

16

15

12

11

11

9

7

5

5

4

4

3

3

3

14

28

0

298

Percent of

Shopliftings

26.2

14.1

9.4

5.4

5.0

4.0

3.7

3.7

3.0

2.3

1.7

1.7

1.3

1.3

1.0

1.0

1.0

4.7

9.4

0.0

100.0

Cumulative Percent of

Shopliftings 

26.2

40.3

49.7

55.0

60.1

64.1

67.8

71.5

74.5

76.8

78.5

80.2

81.5

82.9

83.9

84.9

85.9

90.6

100.0

100.0

100.0

Cumulative Percent

of Stores

1.3

2.6

3.8

5.1

6.4

7.7

9.0

10.3

11.5

12.8

14.1

15.4

16.7

17.9

19.2

20.5

21.8

30.8

66.7

100.0

100.0

Shopliftings per

1000 Sq. Ft.

1.54

0.70

0.22

0.24

0.28

0.31

0.09

0.16

0.28

2.82

0.16

0.10

0.35

0.12

3.32

0.90

0.02

0.08

0.06

0.00

0.15

Property

1

2

3

4

5

6

7

8

9

10

11

12

13

14

Year

Acquired

1977

1982

1983

1985

1985

1986

1986

1987

1987

1988

1991

1991

1992

1992

Pre-Owning

0

0

0

0

0.1

0.2

0

0

0

0.4

0.2

2.3

1.1

0.2

Post-Owning

1.6

16.9

2.3

4.5

6

27.9

3.4

8.3

11.3

8.1

9.3

21.8

0.7

10.7

No. of Units

4

15

8

8

10

16

6/8

5

12

6

10

10+

4+

4

Average Yearly Arrests

Slumlords, Crime in Low Rent Apartments and Neighborhood Blight

In every large city, a few low-cost rental apartment

buildings make extraordinary demands on police time. These

"risky facilities" are often owned by slumlords -

unscrupulous landlords who purchase properties in poor

neighborhoods and who make a minimum investment in

management and maintenance. Building services

deteriorate, respectable tenants move out, and their place is

taken by less respectable ones - drug dealers, pimps, and

prostitutes - who can afford to pay the rent but who cannot

pass the background checks made by more responsible

managements. In the course of a problem-oriented policing

project in Santa Barbara, California, Officers Kim Frylsie and

Mike Apsland analyzed arrests made at 14 rental apartment

buildings owned by a slumlord, before and after he had

purchased them. The table clearly shows a large increase in

the number of people arrested at the properties in the years

after he acquired them. There was also some evidence that

the increased crime and disorder in these properties spilled

over to infect other nearby apartment buildings - a finding

that supports the widespread belief that slumlords

contribute to neighborhood blight.

Source: Clarke, Ronald and Gisela Bichler-Robertson (1998). "Place Managers, Slumlords and Crime in Low Rent Apartment Buildings".

Security Journal, 11: 11-19.
S

ome people are repeatedly victimized and, in

conformity with the 80-20 rule (Step 18), a small

proportion of victims account for a large proportion

of all victimizations. Ken Pease and Graham Farrell

carefully documented this fact in a seminal Home Office

publication called "Once Bitten, Twice Bitten". Using

British Crime Survey data (see the table), they showed

that about 4% of people experience about 40% of all

victimizations in one year. They showed that repeat

victimization occurs for a variety of crimes including

domestic violence, sexual assault, burglary and car-related

thefts. They also showed that repeats occur quite quickly,

often within a week of the first victimization, though this

varies with the offense.

Research has shown that it is easy to miss the extent of

repeat victimization for several reasons:

• Many victims do not report crimes to the police, which

means that repeat victimization is undercounted in

official police records. This is why researchers have tried

to use surveys, in which people can be asked about

crimes they did not report to the police. Unfortunately,

the National Crime Victimization Survey, the United

States equivalent to the British Crime Survey,

undercounts repeat victimization because it uses only a

6-month recall period and does not count all the crimes

committed in a series against a particular victim.

• Crime analysts often look for repeat victimization by

counting the number of crimes at addresses, but police

data often contains incomplete address information,

especially for apartment units. This leads to higher

estimates of one-time only victimizations than is actually

the case. This difficulty is being reduced by the greater

availability of GIS systems and through the use of

address matching in mapping software (i.e., geocoding).

• Repeat victimization can be underestimated because of

the "time-window effect". If only victimizations during a

specific time period are counted - a time window of

January 2002 through June 2002, for example - then

someone who had been victimized in December 2001

and once during the six-month window would not be

counted as a repeat victim. If they had the misfortune to

be victimized in July 2002, we would not know that this

person had three victimizations. Ideally, a moving

window should be used where each new victim is

followed for a year after the first reported event.

In explaining repeat victimization, Ken Pease distinguishes

two kinds of accounts:

1. Boost accounts explain repetitions in terms of

positive experiences at the initial offense. A burglar, for

example, learns a great deal about a home during a

break-in. This knowledge may encourage him to come

back for another break-in. A burglar may also tell others

about goods he left behind, leading to subsequent

break-ins by other burglars.

2. Flag accounts explain repetitions in terms of the

unusual attractiveness or vulnerability of particular

targets that result in their victimization by a variety of

offenders. Some occupations have much higher

victimization rates than others (taxi drivers, for example)

and people who spend time in risky facilities (such as

convenience store clerks) are also more prone to

repeated victimization. Finally, the ownership of hot

products, such as cars attractive to joyriders (Step 31),

will also increase the probability of repeat victimization.

"Virtual" or "near" repeats involve victims with

characteristics similar to the original victim or target. After

successfully attacking the first target, offenders generalize

to targets with similar characteristics. Houses with the

same lay-out and in the same neighborhood as the first

burglary, for example, can be expected to have higher

risks because the offender has learned something about

them from breaking in before.

2929. Be ready for repeat victimization

Well-intentioned police officers sometimes say this to

reassure burglary victims that they won't be victimized

again. Unfortunately, the research reviewed here shows

that it is not true.

Number of

Crimes

Experienced

0

1

2

3

4

5+

Percent of

Respondents

59.5

20.3

9.0

4.5

2.4

4.3

Percent of

Incidents

0.0

18.7

16.5

12.4

8.8

43.5

About 4 Percent of People Experience About 40

Percent of All Crimes

Source: British Crime Survey, 1992, all offenses

"Lightning never strikes twice in the same place"
Crime Analysis for Problem Solvers in 60 Small Steps

Knowledge of repeat victimization is useful for predicting

who is most at risk and when they are at risk. This means

that crime prevention resources can be focused on these

people, rather than spreading resources over a number of

people, most of whom have a very low risk of crime.

Many police agencies now also use a "graded response"

when dealing with repeat victims. This means that the

more often someone has been victimized the more

intensive the preventive action taken by the police.

Knowing the time period between repeats also makes it

possible to temporarily deploy crime prevention for short

periods when the risk of crime is the greatest. For

example, some police agencies will install temporary

burglar alarms where the risk is high of a repeat burglary

occurring soon.

Read More:

Weisel, Deborah (2004) Analyzing Repeat Victimization,

Problem Solving Tool Series, No. 2. Washington, D.C.:

Office of Community Oriented Policing Services, U.S.

Department of Justice. (accessible at www.popcenter.org

and www.cops.usdoj.gov).

Johnson, Shane and Kate Bowers (2004). "The Burglary

as Clue to the Future: The Beginnings of Prospective HotSpotting." European Journal of Criminology, 1(2),

237-255.

ANALYZE IN DEPTH

Neighbor Beware!

Repeat victimization tells of an elevated risk that the same victim will suffer again, most often in the immediate days

or weeks following the preceding crime. But risk can be communicated to nearby places. Kate Bowers and Shane

Johnson of the Jill Dando Institute of Crime Science have shown how burglary risk is communicated down a street.

This is illustrated in the graph. A home is burgled, which we will call the reference burglary. The numbers at the

bottom are a measure of distance from the reference burglary. A distance of one tells of a home next to a burglary

location on the same side of the street, or the home immediately opposite. A distance of two refers to homes two

doors down on the same side of the street, or diagonally opposite, and so on. The ordinate shows the number of

burglaries following reference burglaries. The data come from Merseyside Police in the UK. You can see that the risk

of another burglary declines the further the distance from the reference burglary. For any given distance, the risk is

greater for homes on the same side of the street. This shows which homes one should seek to protect in the wake of

a burglary. Priority should be given to homes close to the burgled home and especially on the same side of the street.

same side equivalent

opposite side

4500

4000

3500

3000

2500

2000

123456789

number of burglaries

house numbers apart

10
One of the fundamental facts of criminology is that a

small proportion of individuals commit a large

proportion of crime. Data from Marvin Wolfgang's

famous Philadelphia cohort study suggested that around

5 percent of offenders account for 40 percent of crimes.

There are two explanations for repeat offending, the first

of which is that impulsive individuals, with weak social

attachments to others tend to get into trouble more

frequently than less impulsive and more attached

individuals. The second explanation is that people exposed

to more crime and disorder opportunities take advantage

of them and adjust accordingly (see Step 9). Both of these

theories can be true. Impulsive individuals with weak

attachments require routine exposures to crime

opportunities to become repeat offenders.

Repeat offending can be detected by testing for the

presence of the 80-20 rule (Step 18). This can be difficult

in practice because offenders try to remain anonymous, so

the data are seldom comprehensive, and may not even

exist. Intelligence information can provide evidence of

repeat offending, but the quality of this information is

highly variable and seldom comprehensive about the

offender population. We often know far more, and know

it with greater validity, about places and victims than we

know about offenders. Nevertheless, systematic

interviews with offenders and their associates can reveal

very useful information for understanding and addressing

problems (Step 10).

Understanding repeat offenders' objectives and motives

can help create prevention strategies. It can make a

difference to the solution of a vehicle theft problem if the

thieves want to have a good time riding around in a fancy

car, to obtain transportation home after a late night of

partying, or to sell it for cash to support a drug habit. It

can make a difference to the solution of a graffiti problem

if the offenders are marking gang territories, creating

"public art", displaying their affection, or trying to

terrorize local residents of a different religion, race,

or ethnicity.

Successful offending can lead to more offending. This

occurs in three ways:

• Offenders, like others, learn from doing. A successful

crime teaches important lessons. This can lead to the

offender attacking the same target again (see box). But

offenders, like everyone else, can generalize. So they

learn that they may be successful if they attack similar

targets (see Step 29).

• Offenders learn from each other. Information can spread

through individuals working in small groups, group

breakup and new group formation. This underscores the

need to understand offender networks. Police can use

networks to spread information that enhances

offenders' perceptions of risks or of the undesirability of

the target or place. Part of the effort to reduce juvenile

homicides in Boston, Massachusetts for example,

involved highly targeted messages to gang members.

• Successful offending can erode prevention, thus making

subsequent offending easier. A small break in a fence,

for example, will become larger with use. If the influx of

offenders and offensive behaviors is faster than the

responses of guardians and place managers, then a

small problem will become worse.

Many crime prevention techniques rest on the assumption

of a credible threat (Step 40). Closed circuit television

(CCTV) provides a deterrent threat to the extent that

potential offenders believe either that someone is

watching who will take action should they see

misbehavior, or that offenders can be identified and

arrested later based on CCTV recordings. This does not

mean that there have to be many arrests, but a few wellpublicized arrests can reinforce an important message.

And the message may be powerful if it is communicated

through offender networks.

3030. Consider repeat offending

Ken Pease has recently written about the benefits for

detection resulting from a focus on repeat victimization.

Evidence is accumulating that repeat victimizations are

the work of the most committed offenders. He points out

that this raises the intriguing possibility that offender

targeting may be achieved simply by detecting repeated

offenses against the same household or person, since

these offenses are committed by offenders whom one

would in any case wish to target. This kind of offender

targeting avoids allegations of violations of civil liberties,

since it focuses on the most troublesome subset of acts

that prolific offenders commit.

Catch Prolific Criminals by Focusing on Repeat

Victimization
Crime Analysis for Problem Solvers in 60 Small Steps

When there is specific information that a few people are

responsible for most of a problem, it can be productive to

focus on these individuals. The Boston Police Department

reduced homicides among young males by monitoring a

relatively few gang members. Francis Cullen and

colleagues suggest that probation and parole authorities

should learn the specific circumstances under which each

offender gets into trouble, then help offenders develop

plans to avoid these circumstances, and finally monitor

compliance with these plans.

Tackling repeat offending by removing facilitating

environments can be effective. For example, in Staining, a

village in England, a scrap yard served as a receiver for

stolen vehicles, parts, and other loot from thefts. Many of

the associated offenders were known. But despite police

enforcement efforts this problem could not be resolved.

The local constable was able to close the site using laws

governing pollution and other environmental hazards. This

substantially reduced crime in the village. Similarly, police

in the United States often use civil laws to close down

facilities that foster drug dealing, prostitution, and other

crimes and disorder.

Conversely, creating crime opportunities to catch

offenders can make things worse. In the late 1970s and

early 1980s, a number of U.S. police departments

experimented with "sting" operations in which they

created fake markets for stolen goods, documented who

sold such goods to them, and then arrested many thieves.

A number of these operations were evaluated. There is

no evidence that these operations reduced crime. There is

some evidence that they may have increased crime by

providing lucrative and convenient ways to sell stolen

goods. Throughout this manual we have noted the strong

influence facilitating environments can have on promoting

criminal behavior. So one should be very cautious about

creating artificial crime opportunities to round up

unknown prolific offenders.

Information from repeat offenders and their confederates

can be used to identify features of the environment that

facilitate offending. Much of the early crime prevention

implemented in convenience stores was developed from

offender interviews (Step 9). In the early 1970s, the

Lakewood, Colorado Police Department interviewed

convicted burglars and learned a great deal about how

they targeted dwellings and handled stolen goods. The

Newport News, Virginia Police Department used offender

interviews to help analyze thefts from vehicles. An

important piece of intelligence they gained was that

thieves targeted vehicles that the thieves believed

contained drugs. More recently, when the Chula Vista,

California Police Department interviewed car thieves they

found that the thieves had a much simpler method for

stealing cars than investigators had suspected. This

alerted investigators to an unknown vulnerability of older

cars of a particular make. Such information is available

from no other source.

Read More:

Cullen, Francis and colleagues (2002). "Environmental

Corrections: A New Framework for Effective Probation and

Parole Supervision." Federal Probation, 66 (2):28-37.

Kennedy, David and colleagues (2001). Reducing Gun

Violence: The Boston Gun Project's Operation Ceasefire.

Research Report. Washington, D.C.: National Institute 

of Justice.

ANALYZE IN DEPTH
I

n line with the 80-20 principle (Step 18), not all

products are equally at risk of theft because thieves are

very picky about what they will steal. They focus on

relatively few "hot products," such as cars, laptop

computers, DVD players, and cell phones. The hottest

product of all is cash, which Marcus Felson describes as

"the mother's milk of crime." It is the most frequently

stolen item in larcenies, burglaries, and robberies. It fuels

robberies of banks and off-track betting shops, attacks on

payphones, and muggings near ATMs.

People's possessions can help explain their victimization

risks. For example, owning a car doubles the risk of

becoming a crime victim, even when account is taken of

relevant demographic and social variables. And the

particular model of car owned can raise this risk many

times over. To inform people about high-risk cars and to

put pressure on manufacturers to improve security, the

Highway Loss Data Institute in Washington, D.C. publishes

annual data showing the number of theft-related

insurance claims made for each model on the road. The

table shows the five models with the highest and lowest

theft claim frequencies (per 1,000 vehicles on the road)

from among the 305 new models during 2001-2003. The

Cadillac Escalade and Nissan Maxima had claim

frequencies about 30 times higher than the five models

with the lowest claims. Escalades were targeted for their

custom wheels and Maximas for their high-intensity

headlights, which also fit earlier models supplied without

such lights.

Useful as these data are, they do not show which cars are

most at risk from specific forms of theft. However,

research undertaken in the 1980s found that the models

preferred by joyriders were "muscle" cars with powerful

acceleration, such as the Chevrolet Camaro. Those most

often stolen and never recovered were expensive cars

such as Lincolns and Mercedes, and those most often

broken into and stripped of contents were European

models, such as Volkswagens, with good radios that fit a

variety of models. Domestic station wagons, the staples of

family transport, were not at risk of any form of theft.

These were inexpensive, had terrible radios, and joyriders

wouldn't be seen dead in them.

Surveys undertaken by the Loss Prevention Research

Council show that shoplifters consistently choose CDs,

cigarettes, liquor, and fashion items such as Hilfiger jeans

and Nike sneakers. Many of these things can readily be

sold on the street or door-to-door in some places. Police

have paid little attention to the fencing of stolen goods

because it is difficult to prove and attracts relatively light

sentences, but many departments now receive regular

electronic reports on pawnshop transactions. Scanning

these reports will help you keep informed about what

burglars and others are stealing in your area. It will also

help you think about how stolen goods are sold and ways

of disrupting the market.

3131. Know the products that are CRAVED by thieves

Cadillac Escalade EXT (2002-03)

Nissan Maxima (2002-03)

Cadillac Escalade (2002-03)

Dodge Stratus/Chrysler Sebring

Dodge Intrepid

Large luxury pickup

Midsize 4-door car

Large luxury SUV

Midsize 4-door car

Large 4-door car

Highest Theft Claim Frequencies, 2001-03 

Buick LeSabre

Buick Park Avenue

Ford Taurus

Buick Rendezvous 4WD (2002-03)

Saturn LW

AVERAGE ALL CARS

Large 4-door car

Large 4-door car

Large station wagon

Midsize SUV 

Midsize station wagon

Lowest Theft Claim Frequencies, 2001-03 

Claim Frequency

20.2

17.0

10.2

8.3

7.9

0.5

0.5 

0.5

0.7

0.7

2.5

Source: Highway Loss Data Institute (www.hldi.org)
Crime Analysis for Problem Solvers in 60 Small Steps

The acronym CRAVED will help you remember which

goods are most stolen. These are Concealable, Removable,

Available, Valuable, Enjoyable, and Disposable:

• Concealable. Things that can be hidden in pockets or

bags are more vulnerable to shoplifters and other sneak

thieves. Things that are difficult to identify or can easily

be concealed after being stolen are also more at risk. In

some cases, thefts may even be concealed from the

owners of goods, as when lumber or bricks left lying

around on building sites are stolen.

• Removable. The fact that cars and bikes are mobile

helps explain why they are so often stolen. Nor is it

surprising that laptop computers are often stolen since

these are not only desirable but also easy to carry. What

is easy to carry depends on the kind of theft. Both

burglars and shoplifters steal cigarettes, liquor,

medicines, and beauty aids from supermarkets, but

burglars take them in much larger quantities.

• Available. Desirable objects that are widely available

and easy to find are at higher risk. This explains why

householders try to hide jewelry and cash from burglars.

It also helps explain why cars become more at risk of

theft as they get older. They become increasingly likely

to be owned by people living in poor neighborhoods

with less off-street parking and more offenders living

nearby. Finally, theft waves can result from the

availability of an attractive new product, such as the cell

phone, which quickly establishes its own illegal market

(see box).

• Valuable. Thieves will generally choose the more

expensive goods, particularly when they are stealing to

sell. But value is not simply defined in terms of resale

value. Thus, when stealing for their own use, juvenile

shoplifters may select goods that confer status among

their peers. Similarly, joyriders are more interested in a

car's performance than its financial value.

• Enjoyable. Hot products tend to be enjoyable things to

own or consume, such as liquor, tobacco, and DVDs.

Thus, residential burglars are more likely to take DVD

players and televisions than equally valuable electronic

goods, such as microwave ovens. This may reflect the

pleasure-loving lifestyle of many thieves (and 

their customers).

• Disposable. Only recently has systematic research

begun on the relationship between hot products and

theft markets, but it is clear that thieves will tend to

select things that are easy to sell. This helps explain why

batteries and disposable razors are among the most

frequently stolen items from American drug stores.

Read More:

Clarke, Ronald (1999). Hot Products. Police Research

Series. Paper 112. London: Home Office. (Accessible 

at: www.popcenter.org).

ANALYZE IN DEPTH

When cell phones became popular, criminals found ways to clone

them so that they could use them without paying any bills. They used

scanners near airports and hotels to capture the numbers that each

phone transmits in order to send and receive calls. They then created

"clones" of the original phones by re-programming the numbers into

phones they had stolen. The original phone would then be charged

for calls made by the clone. This rapidly became big business. The top

line in the graph shows that the cloning losses for all cell phone

companies increased quite rapidly from June 1992 to June 1996

when they totaled nearly $450 million for the previous 6 months.

(The losses were the charges that the phone companies wiped off the

bills of legitimate subscribers whose phones were cloned.) At this

point, the phone companies began to introduce a variety of

technologies that made it much more difficult to steal phone numbers

and to use a clone. There was a rapid reduction in cloning so that, by

December 1999, it was all but eliminated. Incidentally, the second

most common form of cell phone fraud, "subscription fraud"

(opening an account with a false name and address), did not

skyrocket when cloning was closed down, as displacement doomsters

would predict. This could be because cloning was easy to "massproduce" by organized criminals, whereas subscription fraud is not.

The Rise and Fall of the Cloned Phone

$500m

$450m

$400m

$350m

$300m

$250m

$200m

$150m

$100m

$50m

$0

Tumbling & Cloning Losses

Subscription Frauds

Semi-Annual Fraud Dollar Losses

United States, June 1992 - December 1999

Jun- 92

Dec- 92

Jun- 93

Dec- 93

Jun- 94

Dec- 94

Jun- 95

Dec- 95

Jun- 96

Dec- 96

Jun- 97

Dec- 97

Jun- 98

Dec- 98

Jun- 99

Dec- 99

Source: Clarke, Ronald, Rick Kemper and Laura Wyckoff (2001).

"Controlling Cell Phone Fraud in the U.S.," Security Journal, 14:7-22.
When analyzing a problem, it is always useful to

ask, "why are these persons, places, times, or

events troublesome, when other similar entities

are far less troublesome?" Answering such questions

requires you to compare problem cases to 

non-problem cases.

This kind of comparison is called a "case-control study." A

case-control study involves comparing troublesome

persons, places, times, or events with untroublesome

persons, places, times, or events. The troublesome cases

are called the "cases." The cases to which they are

compared are called the "controls."

An example comes from data supplied by Susan Wernike,

a crime analyst for the Shawnee, Kansas Police

Department. For every bar in Shawnee, she calculated the

calls per 100 persons of rated capacity. This adjusted for

bars of various sizes (see Step 27). The figure shows the

bars ranked from highest to lowest rate. A basic casecontrol study could be applied here. The bars with the

highest rates would be compared to those with the lowest

rates to see if there are systematic differences in the ways

they operate, the behaviors in the bars, and the types of

customers they attract.

Case-control studies are very helpful when the

troublesome cases are rare relative to the untroublesome

ones. This is frequently the situation in problem solving.

To conduct a valid case-control study you should do 

the following:

• Define your cases precisely.

• Select a representative sample of these cases.

• Define a group of controls that could have been

troublesome but did not become troublesome even

though they were exposed to similar conditions (e.g., in

the same neighborhood or city, serve the same types of

clients, etc.).

• Select a representative sample of these controls.

• Compare the characteristics of the cases to the

characteristics of the controls.

Substantial differences indicate characteristics that might

be contributing to the problem. Similarities indicate

characteristics that are probably not contributing to the

problem. Let's explore these steps with an example.

The simple example of Shawnee bars illustrates the first

four steps for a very small number of locations. We can

also examine a more complex example to point out some

of the details of case-control studies.

Define the cases precisely. In the early 1990s, John

Eck was interested in why a few places were persistent

drug dealing locations and most other nearby places were

not. With the help of the San Diego Police Department,

California, over 300 cases of persistent drug places were

identified in one San Diego neighborhood. These were

identified based on citizen calls, drug enforcement actions,

field interrogation records, arrest data, and patrol officer

observations. To be classified as persistent, each site

either had to have more than one drug arrest, call, or field

interrogation on separate days; or a warrant for a raid; or

be identified by a patrol officer. Because multiple

indicators were used to locate these sites, it was

reasonable to believe that most persistent sites 

were located.

Select a representative sample of cases that were

troublesome. For each block in the neighborhood with

a single dealing location, the dealing location was

selected for study. If two dealing locations were on the

block, both were selected. If there were more than two,

two were randomly selected. This provided a

representative sample of 189 locations. Selecting all the

cases was another valid option, but that would have

raised the costs of the study. Simple random sampling

could also have been used, but would not have

guaranteed coverage of all affected blocks.

Define a group of controls that could have been

troublesome. Controls were places in the neighborhood

that showed no evidence of drug dealing. Nearby places

were useful because drug sellers looking for a dealing site

would know them. Therefore, the nearby places were

exposed to dealers but had not been selected by dealers.

Controls should be entities that could have been cases,

but for mysterious reasons did not become so. The

objective of the study is to solve the mystery.

Select a representative sample of controls. On

each block the same number of non-dealing places was

selected as dealing places. These sites were randomly

selected (as would be the case if they were in a lottery)

from a list of places on each block that had no indicators

of drug activity. Selecting all non-dealing locations would

have been impractical, since there were thousands of non3232. Conduct case-control studies
Crime Analysis for Problem Solvers in 60 Small Steps

dealing locations. By making sure cases and controls were

from the same block, the selection process assured that

the controls were exposed to drug dealers. Random

selection assured us that the controls were representative

of all non-dealing locations.

Compare the cases to the controls. Observers were

sent to the cases and the controls to record information

about the sites. This included information on: the type of

structure (business, apartment building, single family

home, vacant lot, etc.); the type of street it was on

(number of lanes, one-way/two way, etc.); the distance

from the nearest interstate highway; the types of

surrounding buildings; the proximity of lighting; the

number of apartment units; the presence of fences and

other security; adjacency to alleys and paths; and many

other factors. The objective was to see if the dealing

locations differed substantially from the non-dealing

locations with regard to any of these characteristics. Two

patterns were found, one for crack-dealing sights and the

other for methamphetamine sites. Compared to controls,

crack locations were more likely to be in small apartment

buildings and have a lockable gate in a fence. Compared

to controls, methamphetamine sites were more likely to

be in single-family homes and adjacent to paths. The

seeming preference of drug dealers for rental units in

small buildings (either buildings with few apartments or

single family homes) suggested that they were looking for

places with low place management. In a later

experiment, Eck found that intervening with landlords did

reduce drug-related crime.

Case-control studies are different from most other studies

and require special techniques to analyze data. Step 33

describes one technique that is particularly useful.

Case-control studies are very useful in problem analysis.

The approach is flexible enough to be applied to a small

number of places (as in the Shawnee example) or a very

large number (as in the San Diego example). Though the

examples focused on places, the same process can be

applied to people, times, and events.

Read More:

Loftin, Colin and David McDowall. (1988). "The Analysis

of Case-Control Studies in Criminology." Journal of

Quantitative Criminology 4:85-98.

ANALYZE IN DEPTH

COMPARING HIGH AND LOW CALL RATE BARS - Shawnee, KS 

FCNHJMDEALBGIK

Bars

Calls per 100 capacity8.00

6.00

4.00

2.00

0.00

compare

Cases Controls

A common mistake is to collect data only on the persons, places, times, or events that are troublesome. This can

provide misleading results because you learn only about characteristics common among the troublesome cases, but

not if they are different from untroublesome cases. An example of this is a study conducted by the FBI in the early

1990s to understand killings of police officers. The researchers collected information on officers killed in the line of

duty, but did not collect information on officers who were exposed to similar conditions but not killed.

Consequently, we do not know which, if any, of the characteristics of the dead officers contributed to their killing.

Living officers exposed to the same conditions may share many of these same characteristics.

Do Not Perform an Uncontrolled Case Study
D

o parking lots with gate attendants, for example,

have fewer thefts from vehicles than parking lots

without gate attendants? Are apartment buildings

with on-site managers at less risk of having drug dealing

than ones without such managers? To answer questions

like these you will need to determine if there is a

statistical association between some characteristic of

persons, places or events and some measure of the

problem (crime, injury, etc.).

There are many ways to calculate association. Often a

correlation coefficient is used. Correlation coefficients

range from -1 to 1. A negative correlation means an

increase in one characteristic is associated with a decline

in the other (and a decline is one associated with an

increase in the other). A positive correlation means that

an increase in one characteristic is associated with an

increase in the other (and a decline in one is associated

with a decline in the other). Big coefficients mean strong

associations (positive or negative). If a correlation

coefficient is near zero, there is an absence of association

- a change in one characteristic is unrelated to a change

in the other. Any spreadsheet or statistical analysis

program can perform the calculations.

The Crime Analysis Unit of the Jacksonville-Duval County

(FL) Sheriff's Department examined apartment complexes

over 50 units. They found that for the 269 apartment

complexes, the correlation between number of units and

number of crimes is about .57: a modest positive

correlation. There is a very high positive correlation (.91)

between the number of property crimes and the number

of violent crimes in these apartment complexes.

You cannot use a correlation coefficient to measure

association in a case-control study (Step 32). Instead, you

should use an odds ratio.

Odds ratios can be any number greater than zero. When

an odds ratio is equal to one, there is no association

between the characteristic and the outcome. That is, the

risk of the outcome is the same whether or not the

characteristic is present. If the odds ratio is between 0

and 1, risk is higher when the characteristic is absent than

when it is present (a negative association). An odds ratio

of .1 indicates the risk of the outcome when the

characteristic is present is a tenth of that when the

characteristic is absent. If an odds ratio is greater than 1,

the risk is higher when the characteristic is present than

when it is absent (a positive association). An odds ratio

of 3 means that the risk of the outcome is three times as

large when the characteristic is present than when it 

is absent.

To use an odds ratio both the outcome and the

characteristic must have only two values. For example, for

the outcome, 1 means that a bar is a high crime bar and

0 means that it is a low crime bar. For the characteristic,

1 means that the staff has been trained how to prevent

assaults, and 0 means that the staff has not been so

trained. The odds ratio would tell you whether there is an

association between bars that have staff trained to

prevent assaults and a bar having a great deal of crime.

Here we would expect a negative association, so the odds

ratio would have to be less than one to meet 

our expectations.

Table 1 shows how to calculate an odds ratio. The

outcome is in the row and the characteristic is in the

column. The number of cases with the appropriate value

for both outcome and characteristic is in each cell. Cell A

contains the number of cases that have the characteristic

in question. Cell C contains the number of cases without

the characteristic. Cell B contains the number of controls

that have the characteristic. Cell D contains the number

of controls without the characteristic. The odds ratio can

be computed with a hand calculator using the formula at

the bottom of the table, but many statistical software

packages will also calculate it.

Table 2 illustrates the application of odds ratios in a case

control study of drug dealing places in San Diego (see

Step 32). The outcome is persistent cocaine or heroin

dealing. There were 58 apartment buildings in the study

that had indicators of persistent dealing (cases). There

were also 47 apartments in the study that showed no

indication of any drug dealing (controls). Does the

presence of locked or unlocked gates or on-site managers

influence whether a drug dealer will select the location?

When apartments with unlocked gates were compared to

those locked or with no gates the odds ratio was greater

than one, but this was not significantly different from one

(see Step 53), so we cannot rule out the possibility that

there is no relationship between unlocked gates and drug

3333. Measure association
Crime Analysis for Problem Solvers in 60 Small Steps

ANALYZE IN DEPTH

dealing (recall, when an odds ratio is one, there is no

association). The association between locked gates and

drug dealing is significantly positive. Buildings with

locked gates were almost three and a half times more

likely to have cocaine or heroin dealing than other

apartment buildings. Apartment buildings with on-site

managers had about three-tenths the chance of becoming

dealing sites as the apartments without on-site managers.

This is a statistically significant negative association.

But remember, correlation is not the same as causation. A

correlation suggests that the characteristic in question

might be a contributing cause, but by itself a correlation is

insufficient to demonstrate causation.

Outcome

Yes (1) -- Cases

No (0) -- Controls

Yes (1)

A

B

No (0)

C

D

Total

A+C

B+D

Characteristic

Table 1: Calculating Odds Ratios

Dealing

Non-Dealing

Dealing

Non-Dealing

Dealing

Non-Dealing

Unlocked Gates

16

8

Locked Gates

33

13

On-site Manager

14

24

Locked Gates or No Gates

42

39

Unlocked or No Gates

25

34

No On-site Manager

44

23

Odds Ratio

1.857

Odds Ratio

3.452

Odds Ratio

0.305

Table 2: Apartment Building Security and Drug Dealing

Odds Ratio = (A/B)/(C/D) = (A*B)/(C*B)
C

rime facilitators help offenders commit crimes or

acts of disorder. There are three types of facilitators:

• Physical facilitators are things that augment offenders'

capabilities or help to overcome prevention measures.

Trucks extend offenders' capacity to move stolen goods,

telephones allow people to make obscene phone calls,

and firearms help overcome resistance to robberies.

Some physical facilitators are tools, but others are part

of the physical environment. Felson and colleagues

describe how the old layout of the Port Authority Bus

Terminal in New York facilitated a variety of crimes.

Types of crimes had specific ecological niches created by

the variety of design features in the old station.

• Social facilitators stimulate crime or disorder by

enhancing rewards from crime, legitimating excuses to

offend, or by encouraging offending. Groups of young

men, for example, can provide the social atmosphere

that encourages rowdy behavior at sporting events.

Gangs and organized criminal networks facilitate

criminal activity by their members.

• Chemical facilitators increase offenders' abilities to

ignore risks or moral prohibitions. Some offenders, for

example, drink heavily or use drugs before a crime in

order to decrease their nervousness.

Each type of facilitator acts against particular forms of

situational crime prevention (Steps 39-43). This is shown

in the table. Each facilitator (in the columns) can counter

specific prevention methods (marked by dots). Physical

facilitators help offenders overcome preventive measures

that increase risk or effort. They can also act as

provocations to deviancy. Social facilitators can offset

each of the prevention methods. Bribes, for example,

offset risk. Some crimes require multiple offenders to

offset the effort. Perceptions of target desirability are

often influenced by what is desired by others. What is an

acceptable excuse often depends on what others will

accept. And acquaintances can provoke crime or disorder

through encouragement. Chemical facilitators allow

offenders to ignore the risk and effort involved in

committing a crime, and to make unacceptable excuses.

Because of their capacity to blunt crime prevention, it is

important to identify the role of facilitators in a problem.

Evidence about facilitators can be found in investigative

reports and from investigators, by interviewing victims and

offenders, and by observing social situations. Analysis of

crime reports can be used to determine the association

between crimes and various facilitators.

If facilitators do play a role in the problem, then the next

step is to find the sources of the facilitators. Sources will,

of course, vary by type of facilitator. Physical facilitators

might be readily available, as in the case of rocks for

rioters or public phones for drug dealers. Or they may be

purchased legitimately, as is the case for many burglary

tools. Or they may be stolen, as is sometimes the case

with vehicles used in serious crimes. Once their source is

found, it may be possible to do something about them.

The boxes show measures taken to address the use of

public phones in drug dealing and facilitating

environments around cash machines.

3434. Look for crime facilitators

Crime prevention

method

Increase Risk

Increase Effort

Reduce Rewards

Remove Excuses

Reduce Provocations

Facilitators Used by Offenders to Counter Crime

Prevention Methods

Physical

•

•

•

Social

•

•

•

•

•

Chemical

•

•

•

Type of facilitator used

Before cell phones became widely available, drug dealers

often relied on the use of public phones to make contact

with suppliers and customers. Many ways to stop them

were tried, including:

• City ordinances to license public phones and ban them

or limit their number at specific locations or categories

of location.

• Installation of rotary dials that do not permit outgoing

calls to pagers.

• Modification of phones to block incoming calls.

• Community pressure on local phone companies or the

city government to remove public phones or relocate

them in better lit or supervised areas.

• Permitting only operator-assisted calls or emergency

calls during night hours by blocking coin operation of

the phones.

• Removal or modification of public phones by businesses

such as convenience stores and gas stations.

• Other types of intervention such as increased police

patrols, warning labels on phones, and "hotlines" to

report problems.

Measures to Prevent Use of Public Phones by

Drug Dealers in U.S. Cities 

Source: Natarajan, Mangai and colleagues (1996). Drug

Dealing and Pay Phones: The Scope for Intervention.

Security Journal 7: 245-251.
Crime Analysis for Problem Solvers in 60 Small Steps

Social facilitators depend heavily on whom offenders

associate with, and the settings for the association. Risky

facilities (Step 28), for example, can provide settings for

social facilitation. Gangs provide the social support for

crime. But even legitimate activity can on occasion spark

social facilitation, as in the case with some politically

motivated violence, or college student disturbances

following games against historical rivals.

Chemical facilitators are abundant and frequently

associated with crime and disorder. Alcohol is particularly

implicated as a facilitator. Various mixtures of facilitators

are common, particularly social and chemical in

entertainment venues. Several of the 25 techniques of

situational crime prevention are designed to reduce the

effect of the three kinds of crime facilitators (Steps 

39-43).

New York City

ANALYZE IN DEPTH

*

Los

Angeles

Security Provisions for Bank Cash Machines in New York City and Los Angeles

Required by legislation.

Not required under legislation, but commonly implemented at bank's discretion.

* Required only during non-banking hours for ATMs located inside bank buildings open for customer use.

Source: Guerette, Rob and Ronald Clarke (2003). "Product Life Cycles and Crime Automated Teller Machines and

Robbery." Security Journal 16: 7-18.

Enclosed cash machine within a secured vestibule 

Increased lighting

Transparent windows in facility enclosure.

Elevated mirrors for users

Reduced vegetation near machine

Surveillance cameras

Safety reminders to users 

Security provisions notice to potential offenders

Crime assessment prior to installation of cash machine

Security guard personnel

Reduced cash machine operational hours based on temporal crime patterns in area
STAGES

Preparation

Entering setting

Enabling conditions

Selecting target 

Completing the theft

Exiting the setting

Aftermath

STEPS

Get tools (e.g., screwdriver, duplicate keys, slidehammer, short steel tube)

Select co-offender

Enter parking lot

Loiter unobtrusively

Reject alarmed cars 

Choose suitable vehicle

Enter car (duplicate keys, use screwdriver)

Break ignition lock (tube or slide-hammer) 

Hot wire ignition and start car

Leave parking lot

Use car to joyride

Abandon car on wasteland 

Set fire to car

RESPONSES

Control sales of equipment such as hand scanners and

duplicate keys 

Parking lot barriers; attendants; few entrances 

CCTV and/or regular patrols to deter loiterers

Visible protection of tempting vehicles

CCTV to monitor suspicious behavior; improve natural

surveillance of lot; vehicle alarm to alert security;

vehicle immobilizer 

Attendants or other exit barriers

Vehicle-tracking system activated; vehicle curfew

program; surveillance of dumping sites

We think of crime as over in a flash. It takes just a

few seconds to snatch a necklace in the street,

pick a pocket, or to break into a car. And rare are

the burglars who search every conceivable hiding place.

Instead, they try to leave as soon as they have found

something worth stealing - usually within a few minutes

of entering the house. Snatching the necklace or breaking

into the house is, in fact, just one step in a series of steps

needed to complete each of these crimes.

You should try to understand the sequence of steps

involved in your crime or disorder problem. There are

several approaches that you can follow:

• Leslie Kennedy of Rutgers University and his colleague

Vincent Sacco separate the steps into precursors,

transactions, and aftermath, and have produced a

criminology textbook, The Criminal Event, organized

around these three stages.

• William Haddon has developed a similar classification to

assist thinking about road accident prevention. He

divides preventive actions into pre-crash, crash, and post

crash.

• Derek Cornish uses the concept of crime "scripts" to

guide analysis. The underlying idea is that any particular

category of crime requires a set of standard actions to

be performed in a particular order, just as in the script of

a play. The scenes are the sequential stages of the

crime; the cast consists of the criminals, victims and

bystanders; and the tools they use are the props.

Whichever of these approaches you use, try to list the

sequence of steps the offender must make to complete

the crime. The table below is Cornish's simplified

representation of the many steps that joyriders must

complete, but it shows that the specific act we consider to

be the crime (in this case, taking the car) is preceded by

preparation, and followed by escaping and enjoying the

proceeds. This brings us to the reason for analyzing

crimes in this careful, step-by-step manner: understanding

clearly the sequence of actions required for the successful

completion of the crime will reveal to you many more

points of intervention. In other words, this will broaden

the choice of responses for to you consider in your

project. The final column of the table lists the possible

responses, keyed to each stage of joyriding.

Joyriding is one of the simpler crimes, but you can follow

the same process of breaking the crime down into its

constituent steps for more complex crimes as well. One

example is crowd disturbances (including riots). Clark

McPhail, a leading expert on crowds, created a three-step

process for analyzing all gatherings: the assembling

process, the assembled gathering, and the disbursal

process. Tamara Madensen, a graduate student at the

University of Cincinnati, added two earlier steps: initial

planning and pre-assembly preparation. Police might

send out warnings about hosting large drinking parties to

forestall initial planning. To prevent bonfires, easily

burnable trash should be removed during the preassembly preparations. Police might greet arriving

students to encourage lawful behavior during the

assembling process. When the crowd is assembled, police

can monitor behavior and intervene if trouble develops.

During the disbursement process, police want to make

sure the crowd breaks up quickly and peacefully.

35

Steps in Joyriding and Associated Responses

35. Understand the crime from beginning to end

Source: Cornish, Derek (1994). "The Procedural Analysis of Offending and its Relevance for Situational Prevention." Crime Prevention Studies,

volume 3. Monsey, NY: Criminal Justice Press
Crime Analysis for Problem Solvers in 60 Small Steps

Preventing Deaths of Illegal Migrants

In an unusual application of situational prevention, Rob

Guerette of Florida International University, has

undertaken a careful study for the U.S. Border Patrol of

the circumstances in which illegal migrants die crossing

the U.S.-Mexico border. Each year, some 300 migrants die

in tragic circumstances - for example, by drowning in

canals and rivers, by heat exposure in desert regions, or as

result of vehicle accidents. By tracing the steps that add

the illegal migrants take in crossing the border and trying

to understand the circumstances that lead to loss of life,

he came up with a number of life-saving suggestions. He

classified these suggestions in a two-way grid:

• Across the top, he followed William Haddon's method

and sorted the preventive suggestions into those that

applied before, during, and after the life-threatening

event.

• Down the side of the grid, he followed the crime triangle

and sorted measures by whether they were aimed at (1)

the migrant or the "victim," (2) the "coyote," who is

employed by migrants to get them safely across the

border (the "offender"), and (3) the "place" or

environment, i.e., desert, rivers, urban areas, and 

so forth.

Some of these suggestions were extensions or

improvements of measures already in place, but others

were novel, which shows the value of his approach. Most

of the suggestions are self-explanatory, but more

background is needed to understand some of them (the

numbering follows the table):

1. His research showed that proportionately more females

die from heat exposure.

3. Migrants typically gather in staging towns close to the

border in Mexico where they make contact 

with "coyotes."

4. When highly trained search and rescue agents are

dispatched to make a rescue, Guerette found migrants

are more likely to survive than when regular line agents

are dispatched.

5. To prevent immediate attempts to re-cross the desert in

the very hot months, migrants apprehended at these

times in the Arizona desert were laterally repatriated in

2003 to Mexican towns near the Texas border. This

experiment was effective in saving lives.

6. In 2004, the Mexican authorities agreed to accept

repatriations from Arizona to destinations in the interior

of Mexico.

14. Motorists in Arizona commonly see small bands of

illegal migrants attempting to cross the desert in the hot

months. This campaign would seek their aid in saving

lives by calling a 1-800 number to report the sighting.

15. Border Patrol agents in Arizona told Guerette that

they often had great difficulty in locating a migrant

reported to be in distress by other migrants, whom they

had apprehended. This is because large swathes of the

desert are quite featureless and the directions given by

apprehended migrants are often vague. A systematic

program of temporary desert markings using colorcoding or symbols could ameliorate this difficulty.

ANALYZE IN DEPTH

Migrant

Coyote

Environment

Before life threatening

event

1. Inform female migrants

about dangers of crossing

the desert

2. Implement alert system for

hazardous conditions

7. Implement alert system for

hazardous conditions 

8. Warn coyotes of

prosecution in event of

migrant deaths 

11. Target problematic times

and places

12. Erect barricades at

dangerous crossing points 

13. Post visible warning signs

in risky areas

During life threatening

event

3. Distribute instructions in 

staging towns for migrants

to follow when in distress

4. Expand Border Patrol 

search and rescue capacity

9. Target coyote for arrest

14. "Save a life/report a

migrant" publicity

campaign

15. Desert markers 

After life threatening

event

5. Lateral repatriation

6. Interior repatriation

10. Create task force to 

prosecute coyotes when

deaths occur

16. Continually review data

to detect new patterns of

hazard 
When you have completed your analysis using the

concepts discussed in the previous steps, you

should ask whether it meets the test of a good

newspaper story. Does it adequately answer the 5 W and

one H questions: what, where, when, who, why,

and how?

These same questions structure Barry Poyner's method of

crime analysis by breaking up a larger problem into its

constituent parts. For example, when he was asked by the

Home Office to study "street attacks" in downtown

Coventry and Birmingham (two large cities in England), he

found that the police classified these as robberies and

thefts from the person, but he found that the majority of

incidents fell into a number of quite distinct problems:

• Robbery from street vending booths

• Robbery of drunks

• Money snatched while being taken to the bank

• Snatching women's purses

• Wallets/money snatched from the victim's hand after a

verbal ploy

• Thefts from shopping bags

• Pickpocketing at bus stops

This was a much more meaningful characterization of

"street attacks" and was an important first step in

understanding the events. He then began to sort through

the incident reports, trying to arrive at a picture of each

problem that would help him find a response.

Incident reports are quite variable in the information

recorded, especially when the victim is not present and

there are no witnesses. However, Poyner tries to piece the

reports together to get a picture of the particular problem

(see box). For each incident he tries to discover:

• What happened? This entails spelling out the

sequence of events and the actions of those involved

(Step 35).

• Where did it happen? Sometimes the sequence of

events takes place in several locations. For example, a

car might be stolen from a parking lot, moved to a

garage for stripping of valuable parts, and then dumped

on a piece of wasteland. Information may only be

available about the first and last locations. Visiting these

can help explain why the offender selected them.

• When did it happen? Householders or car owners

might know only that their car was stolen or their house

burgled "sometime during the weekend." For many

interpersonal crimes, however, the victim will be able to

report precisely when the crime occurred, which may

permit inferences about such matters as whether the

streets were deserted.

• Who was involved? There is always at least one

offender; there may be one or more victims even if they

have no direct contact with the offender; there may be

witnesses and other third parties. Statements in police

records made by witnesses and victims can provide

much useful information, but it might sometimes be

important to question a sample about the event.

• Why did they act as they did? It is important to

understand the specific benefits that a particular kind of

crime brings to the offender. In many cases of theft, the

motive will be obvious, but for interpersonal crimes and

for vandalism the motives may only emerge from

interviewing offenders (Step 10). Equally important for

prevention may be to understand why victims and

witnesses behaved as they did and to answer such

questions as "What causes some victims to respond by

attacking the offender?" and "Why do witnesses often

fail to intervene?"

• How did the offender carry out the crime? Crime

can be thought of as a process, with several steps from

initiation to completion, rather than a circumscribed act

occurring at a specific point in time. At each step the

offender must make decisions, might need to work with

others, and might need to employ specific knowledge

and tools. This is essentially the idea underlying

Cornish's "script" approach discussed in Step 35. It may

not always be possible to develop detailed scripts, but

the analysis should give a clear picture of how the crime

was accomplished.

Poyner's analysis of pickpocketing at bus stops illustrates

the approach. He was able to construct a detailed

description of the crime by supplementing the rather

sketchy incident report with observations of the lines

waiting for the bus. He found that the peak time for

pickpocketing was the afternoon rush hour, particularly on

Fridays when lines were long. Groups of three or four

youths would hang about near the lines, looking in the

3636. Be sure to answer the five "W" (and one "H") questions
Crime Analysis for Problem Solvers in 60 Small Steps

windows of nearby stores to avoid arousing suspicion,

while watching at the same time for suitable victims.

These were invariably middle-aged or older men who kept

their wallets in the back pockets of their trousers.

(Younger men wore tighter-fitting trousers and did not

keep their wallets in their back pockets.)

As their victims began to board the bus, which used a

pay-as-you-enter system, the youths would run to the

front of the line, jump on the boarding platform of the

bus and jostle the riders. They would ask the driver some

irrelevant question about the destination of the bus.

Meanwhile one of the youths would pick the pocket of

the victim. The victim would be irate at being jostled and

would not realize what was happening. The driver would

shout at the youths to get off his bus and other

passengers would be complaining. The youths would step

off the bus and slip away into the crowd. The youths were

never caught. The victim would only find out later that

his wallet was gone.

This analysis suggested four possible responses:

• Instead of pay-as-you-enter, tickets might be sold in

advance for use at these stops.

• Bus stops might be re-sited away from main pavements

and organized in bays more like a bus station. This

would make it difficult for offenders to lie in wait.

• Use a bus shelter to screen the waiting lines so the

offenders would be unable to identify potential victims

in advance.

• Construct line-marshalling barriers at the boarding point

so offenders could not jump onto the bus platform.

Note that all these solutions are outside the normal remit

of the police. Officers rarely consider that their role

involves, for example, redesigning bus stops. But as a

problem-solving crime analyst your job is to cut crime, and

you may need gently to persuade police colleagues that,

in the widest sense, it is their job, too.

ANALYZE IN DEPTH

"There is a further advantage of combining incidents. In some cases we may have much less detail

than other cases but otherwise the facts we do know about are the same. It may be possible to

reconstruct the missing data in these less well reported incidents in much the same way as the

archaeologist reconstructs broken pottery from an excavation. He may only have a few pieces of the

broken pot but from knowledge of other similar pots he can be reasonably sure about the form of the

whole pot. This archaeological approach is quite helpful when, for example, we may have some

detailed accounts of what offenders do in a few cases where they have been caught. It seems

reasonable to believe that similar behaviour occurred in similar crimes even though the offenders

were not caught."

Working Like an Archaeologist

Source: Poyner, Barry (1986). "A Model for Action." Situational Crime Prevention, Gloria Laycock and

Kevin Heal. London: Her Majesty's Stationery Office.
C

rime prevention often involves predictions. Will

offenders associated with the problem continue to

offend as they have done in the past? Will recent

victims become victims again in the near future? Will hot

spot places become cold spots, or will they stay hot?

Though past behavior may be our best predictor of future

behavior, it is not a perfect predictor.

The examples above deal with predicting the future. But

we also try to probe the unknown in other ways, including

in our responses to problems. A polygraph examiner tries

to assess whether the subject is lying or not. Drug tests

are used to determine if people have recently used illicit

drugs. Metal detectors and baggage screening devices at

airports are used to determine if passengers have

weapons on their person or in their luggage. In all these

examples the examiner is trying to draw a conclusion

about an unknown condition. And just like predictions of

the future, the examiner may make an accurate

assessment or an inaccurate one. Consequently, it is very

important to understand how predictions and other

judgments can fail.

A useful way to examine errors of prediction and

judgment is to compare the prediction to what actually

occurs. The columns in Table 1 show two possible

predictions: Yes, the outcome will occur; and No, the

outcome will not occur. The rows show two actual

outcomes: Yes, the outcome did occur; and No, the

outcome did not occur.

Imagine a large number of predictions. When a prediction

corresponds to the actual, then it is accurate. Cells A and

D contain counts of accurate predictions. You can

calculate an accuracy rate by adding the number of

predictions that fall into these two categories and dividing

by all the predictions made.

Let’s look at cells B and C. When the decision-maker

predicts that the outcome will not occur, but it does occur

then it goes into cell B. This is called a False Positive.

Cases in cell C represent situations in which the decisionmaker has predicted that the outcome would occur, but it

did not. These are False Negatives. You can calculate

error rates for both types by dividing the number of

predictions in each cell by the total number of predictions.

Let’s look at a hypothetical example. To curb crime in

rental housing, a police department facilitates and

encourages landlords to conduct background checks.

Prospective renters with recent histories of criminal

behavior are not accepted. Such a policy implies a

prediction that people with recent histories of criminal

involvement will continue that involvement on or nearby

the rental property and that people without such

backgrounds will not engage in this type of behavior.

Even advocates of such a policy would agree that such

predictions are not perfect, but it would be useful to know

two things. First, does such a policy reduce rental

property crime? An evaluation could answer this

question. But even if it does reduce crime, what are the

negative consequences? To answer this question requires

an analysis of the prediction errors.

If we were able to collect the relevant data we might be

able to create a table like Table 2. We see that the

policy's predictions are accurate. But how do we feel

about the errors? Should something be done about

people without a recent history of prior criminal

involvement who commit crimes? Are too many former

offenders who are not engaging in criminal behavior

being denied housing? 

3737. Know that to err is human

Actual Outcome

YES

NO

YES

A. Accurate

True Positives

C. False Positives

NO

B. False

Negatives

D. Accurate

True Negatives

Accuracy Rate

False Negative Rate

False Positive Rate

(A+D)/(A+B+C+D)

B/(A+B+C+D) 

C/(A+B+C+D)

Table 1: Types of Prediction Errors

Later

Criminal

Involvement

YES

NO

Total

YES

35

35

70

NO

10

496

506

Total

45

531

576

Accuracy Rate

False Negative Rate

False Positive Rate

92.2%

1.7%

6.1%

Table 2: Example of Prediction Error Analysis

Prior Criminal Involvement

35 

35 
Tighter restrictions to curb offending by people who have

no recent criminal record might reduce the false negative

rate, but it could increase the false positive rate,

particularly if the information for making the decisions is

less accurate than the information currently used. On the

other hand, making distinctions among applicants with a

recent criminal history could decrease the false positive

rate, but at the expense of increasing the false negative

rate. Such tradeoffs are quite common.

Further, we may regret one type of error more than

another. If the types of crimes being prevented by the

landlords are relatively minor, then the false positive rate

might be too high. But if these are crimes of serious

violence being averted, then the false negative rate may

be of greater concern. The consequences of the errors are

very important and people often disagree over these.

Another source of disagreement are the error rates

themselves. Such rates are often very difficult to estimate.

Consider the shaded boxes in Table 2. Under most

circumstances, these figures will be unknown. The

landlords might count how many people they turned away

because of a criminal record, but they cannot tell us what

such people would do if they had not been turned away.

In other situations the shoe is on the other foot; false

positives may be known with some precision, but false

negatives are unknown. In airport screening, false

positives are known because predictions of having

contraband are followed by closer scrutiny. A passenger

who security personnel believe is carrying a firearm will

be subject to a very careful search, thus revealing if the

initial prediction was accurate or inaccurate. However,

false negatives are not known with much reliability. A

passenger, who carries contraband past airport security

may not be checked again, So we cannot learn that she

was a false negative.

In some circumstances it is possible to use a pilot test to

accurately estimate the errors by making the predictions,

not acting on them, and carefully observing what

happens. This might be difficult to do with offenders, who

prefer to keep their misdeeds hidden, but it could work

with potential victims or crime places. For example, a

response to a problem might involve predicting which

places are most likely to be crime sites and then

intervening at those locations. Prior to implementing this

response, a pilot study could be conducted in which the

predictions are made, but no action is taken. If the error

rates are unacceptably high, then it might not be worth

implementing the response.

Crime Analysis for Problem Solvers in 60 Small Steps

ANALYZE IN DEPTH
T

he first inclination of police, even when they have

been involved in a detailed analysis of a problem, is

to try to solve it by beefing up enforcement. You

should expect this and not oppose it, even if the impact is

usually short-lived. But from the beginning you should be

helping your police colleagues find more permanent

solutions. Local community partners could provide this

help, but instead they often promote their own agendas

and push solutions with limited impact. The result is often

a compromise package of measures, none of which is

effective, but each of which may satisfy one or other of

the parties. In fact, the disagreements over solutions may

lead to a loss of momentum and nothing may be 

properly implemented.

You can help to stop this from happening, but you must

first become an expert on solutions. For example, if the

problem is one of car theft, you must be able to speak

authoritatively about the ineffectiveness of decoy vehicles

or "lock your car" campaigns. If it is a burglary problem,

you must know the results of research on burglar alarms

or improved street lighting, both of which may be

suggested as solutions. You should also be thoroughly

familiar with findings on displacement, since innovative

solutions are often blocked by knee-jerk invocations of

this theory.

To become an expert on solutions you must know how to

find out more about particular responses by undertaking

rapid literature searches (Step 19). You must also become

an expert on situational crime prevention, the science of

reducing opportunities for crime. Situational prevention

uses the same action-research methodology as problemoriented policing and has dozens of evaluated successes

to its credit. Much of the knowledge about displacement,

diffusion of benefits, repeat victimization, and many other

concepts discussed in this manual have been developed

by situational prevention researchers. The next five steps

discuss the 25 techniques of situational crime prevention,

which fall into five main groups (see box). These are

defined by what Nick Tilley of the University of

Nottingham Trent in the U.K. calls the mechanism through

which the techniques achieve their preventive effect:

increasing the effort of crime, increasing the risks,

reducing the rewards, reducing provocations and

removing excuses.

At this point, you might be asking yourself why you

should assume this responsibility for identifying solutions.

Isn't it enough that you carry most of the burden at the

scanning, analysis, and assessment stages? And even if

you did take on this role, why should anyone pay

attention to you? But to become a problem-solving

analyst you must go beyond your traditional analytic

function. You must become a full and equal member of

the problem-solving team. You may be relatively junior,

but your authority comes from your expert knowledge, not

your position. People will listen if you make novel

suggestions, or if you provide supporting evidence for

other people's good ideas.

3838. Embrace your key role at response

Twenty-Five Techniques of Situational Crime Prevention

Increase The Effort

Increase The Risks

Reduce The Rewards

Reduce Provocations

Remove Excuses

1. Target harden

2. Control access to facilities

3. Screen exits

4. Deflect offenders

5. Control tools/weapons

6. Extend guardianship

7. Assist natural surveillance

8. Reduce anonymity

9. Use place managers

10. Strengthen formal surveillance

11. Conceal targets

12. Remove targets 

13. Identify property

14. Disrupt markets

15. Deny benefits

16. Reduce frustrations and stress

17. Avoid disputes

18. Reduce arousal and temptation

19. Neutralize peer pressure

20. Discourage imitation

21. Set rules

22. Post instructions

23. Alert conscience

24. Assist compliance

25. Control drugs and alcohol
Criticism

1. It is simplistic and atheoretical.

2. It has not been shown to work; it displaces crime 

and often makes it worse.

3. It diverts attention from the root causes of crime.

4. It is a conservative, managerial approach to the

crime problem.

5. It promotes a selfish, exclusionary society.

6. It promotes Big Brother and restricts

personal freedoms.

7. It blames the victim.

Rebuttal

It is based on three crime opportunity theories: routine

activity, crime pattern, and rational choice. It also draws

on social psychology.

Many dozens of case studies show that it can reduce

crime, usually with little displacement.

It achieves immediate results and allows time for finding

longer-term solutions to crime.

It promises no more than it can deliver. It requires that

solutions be economic and socially acceptable.

It provides as much protection to the poor as to the rich.

The democratic process protects society from these

dangers. People are willing to endure inconvenience and

small infringements of liberty when these protect them

from crime.

It empowers victims by providing them with information

about crime risks and how to avoid them.

Crime Analysis for Problem Solvers in 60 Small Steps

You should always opt for solutions that could bring a

rapid reduction in the problem. This means that you must

focus on the immediate, direct causes of a problem rather

than the more distant, indirect ones. This important

distinction has been developed by Paul Ekblom of the

Home Office, and can be illustrated by the problem of bar

fight injuries caused by broken bottles and glasses.

Distant "root" causes might include racial discrimination

producing a generation of disaffected minority youths,

lack of local employment opportunities resulting in widespread social exclusion, and the premium placed on a

"tough" reputation in a deprived and lawless community.

More immediate, situational causes might include

irresponsible serving practices promoting drunkenness in

local bars and taverns, and the immediate availability of

bottles and glasses that can easily be used as 

deadly weapons.

Rapid and sustained reductions in crime can only result

from addressing situational causes; addressing root

causes, even if we knew what to do about them, can only

pay off in the comparatively distant future - long after the

current stakeholders have any remaining interest in the

problem. Meanwhile, unless the immediate causes are

dealt with, broken glasses and bottles will continue to

claim victims.

Some situational solutions can also take a long time to

implement. For example, the danger posed by glasses and

bottles could be addressed by legislation requiring bars

and taverns to use only toughened glasses and bottles

that disintegrate into crumbs when broken. This would

probably take years to accomplish. Much more realistic

would be to bring community pressure to bear on local

taverns to serve beer only in toughened or plastic glasses

and to refuse to sell bottles at the bar. This ought to be

achievable in a much shorter time. You might have a

particular analytic role in promoting this solution by

assembling data about the likely costs for the pubs and

the reduced costs of injuries and emergency care. In fact,

it will probably fall to you (who else?) to collect data

about the feasibility, costs and the public acceptability of

any of the measures that are being seriously considered

by the problem-solving partnership.

The bottom line is that you must acquire knowledge of a

broad range of solutions, and be prepared to fight for

good ideas, if your careful analytic work is to bear fruit.

Read More:

Clarke, Ronald (1997). Situational Crime Prevention:

Successful Case Studies (2nd ed.). Monsey, NY: Criminal

Justice Press.

Von Hirsch, Andrew, David Garland and Alison Wakefield

(2000). Ethical and Social Perspectives on Situational

Crime Prevention. Oxford: Hart Publishing.

FIND A PRACTICAL RESPONSE

Seven Criticisms of Situational Crime Prevention - and Rebuttals
H

ere we describe the most basic category of

situational measures - those designed to increase

the difficulties of crime - beginning with target

hardening. Situational prevention is sometimes dismissed

as being nothing more than this, though it is only one of

the 25 techniques that the approach encompasses. Note

that there is considerable overlap between the techniques.

For example, target hardening makes crime more difficult,

but it can also slow up offenders and increase their

chances of getting caught. Some measures can also serve

more than one purpose. When using this classification, do

not spend time worrying where a particular measure fits -

use it only to ensure that you consider the widest possible

repertoire of situational responses to a particular problem.

Harden targets. An obvious, often highly effective way

to obstruct the vandal or the thief is through physical

barriers such as locks, screens, or reinforced materials. The

introduction more than 30 years ago of steering locks in

this country and overseas brought about long-term

reductions in car theft, and ignition immobilizers are now

reinforcing these benefits. Anti-robbery screens in London

post offices have reduced robberies by 40 percent and

bullet-resistant passenger screens have cost-effectively

reduced assaults and robberies committed against cab

drivers in New York City (see Robbery of Taxi Drivers,

Problem-Oriented Guides for Police No. 27, accessible at

www.cops.usdoj.gov and www.popcenter.org).

Control access to facilities. Keeping people out of

places they have no right to be, such as military camps,

factories, and apartment blocks, has a long pedigree -

think only of the portcullises, moats, and drawbridges of

medieval castles. It is also a central component of Oscar

Newman's concept of defensible space, arguably the start

of scientific interest in situational prevention. Barry Poyner

has demonstrated that the installation of entry phones

and the demolition of walkways linking buildings

significantly reduced muggings at a London estate (Step

24). In some cases, access controls are intended to ensure

the possession of tickets and documents. The redesign of

tickets to make them easier to check produced a sharp

reduction in fare evasion on Vancouver, Canada ferries. In

the most famous example, baggage and passenger

screening at airports in the early 1970s contributed to a

reduction in the number of airline hijackings worldwide

from about 70 to 15 per year.

Screen exits. The purpose of exit screening is to ensure

that those leaving a building, a facility, or some other

place have not stolen anything or have paid all fees and

taxes. Passengers on the Washington, D.C. subway must

insert their tickets in the automatic gates not only when

entering the subway, but also on leaving. This provides

two opportunities to check that the fare has been paid.

On the New York City subway, passengers must insert

their tickets in the gates only once, when entering the

subway, thus reducing the chances of detecting fare

evasion. Other examples of exit screening include border

controls on leaving a country and the use of electronic

tags in library books and merchandise. These tags activate

an alarm if books have not been checked out or if a thief

tries to remove a tagged item from the store. Studies have

shown that they significantly reduce shoplifting and theft

of library books.

Deflect offenders. Rival groups of soccer fans in the

U.K. are segregated in the stadium to reduce fighting, and

their arrival and departure is scheduled to avoid the

waiting periods that promote trouble. Scheduling the last

bus to leave immediately after pub closing time is

intended to interfere with another of Britain's less

admirable traditions, the closing time brawl. These are

examples of deflecting offenders away from crime targets,

a situational technique suggested by routine activity

theory. Other examples are provided by road closure

schemes that have produced reductions in many kinds of

crime (see Closing Streets and Alleys to Reduce Crime,

Problem-Oriented Guides for Police, Response Guide No.2,

accessible at www.cops.usdoj.gov and

www.popcenter.org). Even drive-by shootings in Los

Angeles have been reduced by street closures (see box).

3939. Increase the effort of crime

Harden targets • Steering column locks and ignition immobilisers

• Anti-robbery screens in banks and post offices

• Bullet-resistant shields for cab drivers

Control access to facilities • Entry phones for apartment complexes 

• Electronic card access to garages and offices

• Defensible space designs for public housing

Screen exits • Ticket needed to exit

• Export documents 

• Electronic tags for stores and libraries

Deflect offenders • Separation of rival fans in stadium

• Street closures 

• Separate bathrooms for women 

Control tools and weapons • Safer guns 

• Toughened beer glasses

• Stop incoming payphone calls to foil drug dealers 

• Photos on credit cards and thumbprints on checks

Increase The Effort Of Crime
Crime Analysis for Problem Solvers in 60 Small Steps

Control tools and weapons. Saloons in the Wild West

routinely required customers to surrender their pistols on

entry because of the risk of drunken gunfights. More

recently, so-called "safer" handguns have been developed

that can only be fired by the owner or which shoot wax

bullets or tranquilizers. To prevent glasses being used as

weapons when broken, many pubs in the U.K. now use

"toughened" beer glasses. The first commercial use of

Caller-ID (in New Jersey at the end of the 1980s)

produced a 25 percent reduction in obscene telephone

calls. Step 34 lists the different ways in which cities have

attempted to control the use of public phones in drug

dealing, including blocks on incoming calls and banning

them from specific locations. Re-programming of public

phones at the Manhattan bus terminal prevented illegal

access to international phone service, thus wiping out a

multi-million dollar scam perpetrated by hustlers.

Improved security procedures for delivering credit cards

produced a substantial drop in credit card frauds in this

country in the mid-1990s (Step 11).

FIND A PRACTICAL RESPONSE

Rival gangs often settle disputes by shooting at

members of the other gang from moving cars. These

"drive-by shootings" are difficult to prevent through

youth work or by intensified policing. A novel solution,

Operation Cul de Sac, was tried in one 10-block area in

Los Angeles, which had experienced the city's highest

level of drive-by shootings and gang homicides. The

police installed traffic barriers on the most affected

streets. These dead-end streets prevented cars from

entering at one end and required those that did enter at

the other end to return the same way. This not only

made it more difficult for shooters, but also increased

their risks because when they returned the same way,

their targets could have their own guns ready.

The barriers brought about an immediate reduction in

drive-by shootings and homicides. In the year before

Operation Cul de Sac, 1989, seven homicides were

committed in the area. In the 2 subsequent years, after

the barriers were installed, only one homicide was

recorded. There was no evidence that homicides had

been displaced to another neighbourhood. At the

conclusion of Operation Cul de Sac, when the barriers

were removed, homicides increased again to their

previous level.

A Designer Solution to Drive-by Shootings

Source: Lasley, James (1998) "Designing Out" Gang

Homicides and Street Assaults. Research in Brief, National

Institute of Justice. Washington, D.C.: U.S. Department of

Justice.
A

ccording to interviews with offenders, they worry

more about the risks of being apprehended than

about the consequences if they are caught. This

makes sense because they can do little to avoid

punishment if caught, but they can do a lot to reduce the

risks of capture by being careful. This is why situational

prevention seeks to increase the risks of being caught and

makes no attempt to manipulate punishment.

Extend guardianship. Cohen and Felson showed that

the increase in residential burglary during the 1960s and

1970s was partly due to the increasing numbers of

women working outside the home. This meant that for

much of the day many homes, if not entire suburbs, had

no "capable guardians." Other research has found that

burglars prefer to commit their crimes on weekday

afternoons when people are likely to be out. This explains

why people should cancel newspapers and inform their

neighbors when they go on vacation. Carrying a cell

phone or going out at night in a group are other ways to

extend guardianship. Little is known about the

effectiveness of these routine precautions and evaluations

of neighborhood watch, the only systematic effort to

extend guardianship, have not been encouraging.

However, "cocoon" neighborhood watch, under which

surrounding homes were alerted after a burglary, was an

important element of a successful project in Kirkholt 

in England.

Assist natural surveillance. Homeowners trim bushes

near their windows and doors and banks light their

interiors at night to capitalize on the "natural"

surveillance provided by people going about their

everyday business. Enhancing natural surveillance is also

the prime objective of improved street lighting and

defensible space architecture. Studies in the U.K. have

found that improved lighting in public housing reduces

crime with little evidence of displacement. One

component of an early CPTED intervention to reduce

burglary in a commercial strip in Portland, Oregon, was

improved lighting of the outside of stores. Oscar Newman

has reported successes in reducing crime in public housing

through the application of natural surveillance principles.

Finally, informant hotlines and crime-stopper programs are

attempts to capitalize on the natural surveillance provided

by the public.

Reduce anonymity. Expanded car ownership has

allowed people to work far from their homes. The

development of out-of-town malls has led to the decline

of downtown shopping. Low-cost travel has led to

increased tourism both at home and overseas. As a result,

people spend increasing periods of time among

anonymous strangers. The building of large schools has

contributed to this trend because pupils are less well

known to staff and other pupils. Reducing anonymity is a

promising but rarely used situational technique. Some

schools are now requiring uniforms, partly to reduce the

anonymity of pupils on their way to and from school. Cab

driver ID badges and "How's my driving?" decals with 1-

800 numbers on trucks are two further ways of 

reducing anonymity.

Use place managers. In addition to their primary

function, some employees also perform a surveillance role.

These "place managers" include sales assistants, hotel

door-men, and parking lot attendants. Canadian research

has found that apartment complexes with doormen are

less vulnerable to burglary. Rewarding cashiers for

detection of forged or stolen credit cards helped to reduce

annual fraud losses by nearly $1 million at an electronics

retailer in New Jersey. Vandalism on a large fleet of

double-decker buses in northern England was

substantially reduced when a few of the buses were fitted

with video cameras for drivers. Having two clerks on duty,

especially at night, has consistently been found effective

in preventing robbery of convenience stores (see table).

Strengthen formal surveillance. Formal surveillance is

provided by police, security guards, and store detectives,

all of whom furnish a deterrent threat to potential

offenders. Burglar alarms, video cameras, and speed

cameras can enhance this surveillance. A study of an

affluent community near Philadelphia found that

widespread ownership of burglar alarms reduced police

costs by lowering burglary rates for the community at

large. Home Office studies have found appreciable

reductions in a variety of crimes following installation of

video cameras in British cities (see Video Surveillance of

Public Spaces, Problem-Oriented Guides for Police,

Response Guide No.3, accessible at www.cops.usdoj.gov

and www.popcenter.org). An evaluation of photo radar

deployed state-wide in Victoria, Australia, showed that it

reduced speeding and contributed to a 45 percent

4040. Increase the risks of crime
Crime Analysis for Problem Solvers in 60 Small Steps

reduction in traffic fatalities. A well-publicized bike patrol

provided by a private security company in a large parkand-ride lot in suburban Vancouver, Canada led to a

substantial drop in theft of cars. When security personnel

began systematic, daily counts of high-risk merchandise,

such as VCRs and camcorders, thefts by employees

dropped by more than 80 percent in the warehouse of a

New Jersey electronics superstore. Powerful new ways of

enhancing formal surveillance are provided by linking

data-sets on individuals, as shown in a study by Eckhart

Kuhlhorn. He demonstrated that computerized

crosschecking of statements of personal income made by

claimants to two separate Swedish government

departments reduced welfare frauds. When people

claimed for rent allowance they were tempted to

understate income, but when they claimed sickness

benefits, they were tempted to overstate it. The ability to

crosscheck the income statements substantially reduced

these frauds.

Read More:

Painter, Kate and Nick Tilley (1999). "Surveillance of

Public Space: CCTV, Street Lighting and Crime

Prevention." Crime Prevention Studies, volume 10.

Monsey, NY: Criminal Justice Press. (Accessible in part at

www.popcenter.org).

FIND A PRACTICAL RESPONSE

Measures that Reduce Robbery of

Convenience Stores

(Results of 14 Studies)

Two or more clerks

Good cash handling

No concealed entrances

Nearby stores

Clear view of store front

Closed at night

Security technology

Cashier in secure booth 

Employee training 

Clear view inside store

Gas pumps at front 

Cashier in center of

store

Store on busy street

Security guard present

Number of supporting

studies*

10

8

6

5

5

5

5

4

4

3

3

3

2

2

*Not all studies included all measures 

Source: Hunter and Jeffery (1997). "Preventing

Convenience Store Robbery through Environmental

Design." Situational Crime Prevention: Successful

Case Studies, Ronald Clarke. Monsey, NY: Criminal

Justice Press.

Extend guardianship

• Promote routine precautions such as leaving signs of

occupancy when away from the house, carrying a cell

phone and going out at night in a group

• "Cocoon" neighborhood watch

Assist natural surveillance

• Improved street lighting

• Defensible space design

• Neighborhood watch and informant hotlines

Reduce anonymity

• Cab driver IDs

• "How's my driving?" decals

• School uniforms

Use place managers

• Train employees to prevent crime

• Reward vigilance

• Support whistleblowers

Strengthen formal surveillance

• Speed cameras and random breath testing 

• Video surveillance of downtowns

• Focused bike patrols in parking lots

Increase The Risks Of Crime
R

ational choice theory holds that offenders are

always seeking to benefit themselves by their

crimes. These benefits may not simply be material,

as in theft, because there are many other rewards of

crime, including sexual release, intoxication, excitement,

revenge, respect from peers, and so forth. An important

strand of situational crime prevention is therefore to

understand the rewards of any particular category of

offending and to find ways of reducing or removing them.

Conceal targets. Householders often try to foil burglars

by hiding jewelry or other valuables. They also keep their

curtains drawn to stop thieves from looking through the

windows to see what they own. Some people don't wear

gold chains in public, and others avoid leaving their cars

overnight on the streets if these are models attractive to

joyriders, such as Hondas and Acuras. The table presents

British Crime Survey data showing that cars left on the

street are at very much greater risk of theft than those left

in the owner's garage or driveway. These are all ways to

conceal targets and reduce temptation. Some other

concealment strategies are less obvious. For example,

gender-neutral phone lists can help protect women from

obscene phone calls, and unmarked armored trucks can

reduce the risk of in-transit robbery.

Remove targets. The installation of a machine that

accepted credit cards in a Spanish church brought several

benefits: donors received receipts for tax purposes, the

church received larger gifts, and, since cash was not

deposited, the church reduced its theft risk through

removing targets. An earlier application of this same

situational technique comes from the days of the

Californian Gold Rush. Plagued by robberies of

stagecoaches, one mine started casting gold in 400-

pound cubes. These were too heavy for robbers to carry

away on horseback. More up-to-date examples of target

removal are provided by changes made to pay phones. To

stop people from smashing glass, wall-mounted booths

have been substituted for kiosks in high-risk locations in

the U.K. and prepaid cards that dispense with the need to

store large sums of cash have removed an important

target for theft. Perhaps the most striking example of

target removal is the introduction of exact fare systems

and safes on buses, which dramatically reduced robberies

of bus drivers in New York and in 18 other cities in the

late 1960s.

Identify property. Motor vehicles in developed

countries must be registered and must carry a unique

Vehicle Identification Number (VIN). This is to assist

taxation, but these measures also reduce theft. One of the

last states to require vehicle registration was Illinois in

1934, whereupon vehicle thefts declined from 28,000 in

the previous year to about 13,000. More recently, the

federal Motor Vehicle Theft Law Enforcement Act of 1984

has mandated the marking of all major body parts of

"high-risk" automobiles with VINs. Police "operation

identification" programs have had limited success in this

country, but Gloria Laycock of the Jill Dando Institute of

Crime Science found that property marking undertaken in

three small communities in Wales, combined with

extensive media publicity, halved the number of reported

domestic burglaries.

Disrupt markets. Criminologists and police have

devoted rather little attention to understanding and

disrupting markets for stolen goods. Criminologists have

found it difficult to obtain data about these markets, and

the police have preferred to pay more attention to

catching thieves and burglars than fences, partly because

the penalties for fencing stolen goods are relatively light.

However, if there were no market for stolen goods there

would be few persistent burglars and few thefts of trucks

carrying large loads of tobacco and alcohol. Recent work

for the Home Office by Mike Sutton has awakened

interest in disrupting markets for stolen goods. The

disruptive measures need to be tailored to the nature of

the market and they include systematic monitoring of

pawn shop transactions by the police, crackdowns on

illegal street vendors, and monitoring of small ad sales in

newspapers to detect repeat vendors. Police "sting"

operations - such as bogus used goods stores - should be

avoided because research has found that they may

stimulate theft in the area around the sting.

4141. Reduce the rewards of crime

Car Thefts and Parking Place, England and Wales, British

Crime Survey

Where parked

Garage at home

Drive/carport

Other street

Public parking lot

Car crimes* per 100,000 cars

per 24 hours

2

40

327

454

*Includes theft of, theft from, attempts and deliberate damage

Source: Clarke, Ronald and Pat Mayhew (1998). "Preventing Crime in Parking Lots."

Reducing Crime through Real Estate Development and Management, Marcus Felson and

Richard Peiser. Washington, DC: Urban Land Institute.
Deny benefits. Installing speed humps is a sure way to

deny the benefits of speeding. Security-coded car radios

and ink tags provide further illustrations of crime

prevention techniques. Security-coded radios cannot be

used unless the thief knows the PIN and, according to

studies undertaken in the United States and in Australia,

cars with these radios have lower theft rates. Ink tags are

used in clothing stores to prevent shoplifting. They release

ink if tampered with and indelibly the stain garment to

which they are attached. The thief cannot wear the

garment or sell it, which removes the incentive for theft.

Read More:

Sutton, Mike and colleagues (2001). Tackling Stolen

Goods with the Market Reduction Approach. Crime

Reduction Research Series Paper 8. London: Home Office.

Graffiti-covered subway trains became almost a trademark of New York City in the 1970s and 1980s, and they

frequently appeared in the opening sequences of movies that were set there. The subway authorities had tried

innumerable law enforcement and target-hardening strategies to rid the subway cars of graffiti, but with little result.

Eventually they hit upon a simple idea that brought them success: Once a car had been cleansed of graffiti it would

immediately be withdrawn from service and cleaned again if it attracted fresh graffiti. This effectively denied

"taggers" the benefits of "gettin up" and seeing their handiwork on public display. Because of the huge number of

subway cars, it took six years before all the cars were clean. Nowadays, they are no worse than subway cars in other

cities.

Crime Analysis for Problem Solvers in 60 Small Steps

FIND A PRACTICAL RESPONSE

Conceal targets

• Off-street parking for cars attractive to joyriders

• Gender-neutral phone directories

• Unmarked armored trucks

Remove targets

• Removable car radios

• Women's shelters

• Pre-paid cards for payphones

Identify property

• Property marking

• Vehicle licensing and parts marking

• Cattle branding

Disrupt markets

• Checks on pawn shops

• Controls on classified ads

• License street vendors 

Deny benefits

• Ink merchandise tags

• Graffiti cleaning

• Disable stolen cell phones

Clean Cars

Year

Goal

Actual

1984

—

400

1985

1720

1915

1986

3434

3454

1987

4707

4839

1988

5946

6077

1989

6221

6245

Source: Sloan-Howitt, Maryalice and George Kelling (1997) "Subway Graffiti in New York City: ‘Gettin up’ vs. ‘Meanin

it and Cleanin it.’" Situational Crime Prevention: Successful Case Studies, Ronald Clarke, Monsey, NY: Criminal Justice

Press.

Reduce Rewards

Denying The Benefits Of Graffiti
When studying prisons and pubs, Richard Wortley

noticed that crowding, discomfort, and rude

treatment provoked violence in both settings. This

led him to argue that situational prevention had focused

too exclusively on opportunities for crime and had

neglected features of the situation that precipitate or

induce crime. As a result of his work, Clarke and Cornish

have included five techniques to reduce what they called

"provocations" in their new classification of situational

techniques. These techniques are explained below,

drawing on Wortley's examples.

Reduce frustration and stress. Everyone gets angry

when treated rudely by waiters, when people push in front

to be served, or when trains are delayed with no

explanation. Sometimes they get so angry they become

violent. This could be avoided by improved service, which

is increasingly being demanded and delivered. However,

complaints may be ignored when those mistreated have

little power. For example, prisoners are often ignored

when they complain that they cannot eat when hungry or

choose their TV programs, even though these complaints

could be met quite easily by staggering meal times and

providing more TVs. Waiting one's turn to use the phone,

another source of frustration for prisoners, can be reduced

by computerized systems to ration phone use (see box).

Outbursts of anger and violence can also result from

people being subjected to extreme discomfort - too much

noise, being jostled, and having nowhere to sit. These

conditions exist in many clubs, bars, and delayed

passenger airline flights and have consistently been found

to induce trouble. More seating, soothing music, and

muted lighting are all ways to reduce stress in 

these settings.

Avoid disputes. In the U.K., rival groups of fans are

segregated in soccer stadiums and their arrival and

departure is scheduled to avoid the periods of waiting

around that promote trouble. Taxi fares from New York

City's Kennedy Airport to Manhattan are fixed at a

standard $45 to prevent cheating and disputes over fares.

In an attempt to produce consensual crowd management

at the Australian Motorcycle Grand Prix, riders were

allowed to operate camp-sites for their fellow

motorcyclists and were encouraged to develop rules for

use of the facilities. This helped to eliminate the brawls

between police and motorcyclists, which had marred the

event in previous years.

Reduce arousal and temptation. Male doctors should

not conduct detailed physical examinations of female

patients without a nurse or receptionist present. This

protects the doctor from false accusations, but it also

reduces the temptation to sexually abuse the patient or

make inappropriate advances. Laws that prohibit

convicted pedophiles from taking jobs involving contact

with children not only protect children, but also help

adults to manage their sexual desires. That the very sight

of a gun has been found to trigger feelings of aggression

provides one good reason for regulating the display of

weapons. Similarly, the fact that high proportions of sex

offenders own or use violent pornography provides a

rationale for controlling these materials. Finally, reducing

temptation is the basis for advice about being careful with

one's money in public as well as advice to young women

about being careful when out alone at night.

Neutralize peer pressure. Many parents discourage

friends who are a "bad influence" on their children and

schools disperse groups of troublemakers into different

classes. But adults as well as children are subject to peer

pressure. Existing staff may induct new workers into

stealing from their employers, and young men are often

encouraged to drink too much by friends. One publicity

campaign mounted in Australia to reinforce the powerful

deterrent impact of random breath testing made use of

the slogan, "Good mates don't let mates drink and

drive." A publicity campaign in this country used "Friends

don't let friends drive drunk."

Discourage imitation. All new television sets contain a

"V-chip" so that parents can program their TVs to prevent

children from viewing violent programs. Though the link

between violent movies and violence in society is much

disputed, there is some evidence of "copycat" crimes

because media reports of unusual crimes sometimes

provoke imitation elsewhere. It has also been shown, for

example, that students who see their teachers engaging in

illegal computer activity are more likely to commit

computer crimes themselves, and that other pedestrians

will follow someone crossing against a red light. Indeed,

how often have you "run the red" only to find when

glancing in your rear-view mirror that so has the car

behind you? It has also been shown that picnic tables in

parks that had been scratched and carved are more than

twice as likely to attract further damage. Findings such as

these provide the rationale for "rapid repair" programs to

4242. Reduce provocations
Crime Analysis for Problem Solvers in 60 Small Steps

deal with vandalism. Wilson and Kelling extended this

principle in their famous "broken windows" article by

arguing that the failure to deal promptly with minor signs

of decay in a community, such as panhandling or soliciting

by prostitutes, can result in a quickly deteriorating

situation as hardened offenders move into the area to

exploit the breakdown in control.

Read More:

Wortley, Richard (2001). "A Classification of Techniques

for Controlling Situational Precipitators of Crime." Security

Journal, 14: 63-82.

FIND A PRACTICAL RESPONSE

Reduce frustration and stress

• Efficient lines and polite service

• Expanded seating capacity

• Soothing music and muted lighting

Avoid disputes

• Separate enclosures for rival soccer fans

• Reduced crowding in pubs

• Fixed cab fares 

Reduce arousal and temptation

• Controls on violent pornography

• Prohibitions on pedophiles working with children

• Advice about avoiding sexual victimization

Neutralize peer pressure

• "Idiots drink and drive"

• "It's OK to say No"

• Disperse troublemakers at school

Discourage imitation

• Rapid repair of vandalism

• V-chips in TVs

• Censor details of modus operandi to avoid 

"copycat" crimes

Rikers Island, a stone's throw from New York City's La Guardia Airport, is a huge system of 10 jails. These house

different categories of inmates, whose phone privileges vary with their status. Corrections officers were supposed to

use logbooks to record phone use and to regulate the amount of time each inmate spent on the phone. In the early

1990s, this system had broken down. Inmates had developed their own system, known as "slot time", and the

annual cost of calls had escalated to more than $3 million. The most powerful inmates controlled the phones, which

they often used to access their beepers and maintain their drug businesses in the outside world. Inmates were also

accessing "sex lines" and were using stolen credit card numbers to make long distance calls and purchases. Nancy

La Vigne, who studied this problem as a graduate student at Rutgers University, notes, "The female inmates did just

this, accessing the Victoria Secrets catalogue, which resulted in a jail that could boast the best-dressed inmates in the

country - until officials caught on." 

The officials introduced a high-security computerized phone system that put strict limits on phone use, in line with

the status of the caller. Detainees gained access to the phones through bar codes on their ID cards and by entering a

PIN. This system immediately cut phone costs in half, but it was also noticed that fewer fights were erupting over

access to the phones. In fact, La Vigne's study showed that the monthly rate of these fights dropped from 6.7 per

1,000 inmates in the year before the new phone system to 3.6 per 1,000 after its introduction.

Reduce Provocations

Phone Fraud, Slot Time, and Victoria Secrets at Rikers Island

Source: La Vigne, Nancy (1994). “Rational Choice and Inmate Disputes over Phone Use on Rikers Island". Crime

Prevention Studies, volume 3, Ronald Clarke. Monsey, NY: Criminal Justice Press.
T

his fifth category of situational techniques recognizes

that offenders make moral judgments about their

behavior and that they often rationalize their conduct

to "neutralize" what would otherwise be incapacitating

feelings of guilt or shame. They make such excuses as:

"He deserved it," "I was just borrowing it," and "I only

slapped her." These excuses may be especially important

for ordinary people responding to everyday temptations to

evade taxes, drive when drunk, sexually harass junior

employees and steal employers' property.

Set rules. All organizations make rules about conduct in

their fields of governance. For example, businesses

regulate employees' time-keeping and stores require sales

assistants to follow strict cash-handling procedures.

Organizations such as hospitals, public libraries and hotels

must, in addition, regulate the conduct of the clients they

serve. Any ambiguity in these regulations will be exploited

if it benefits the client. One important strand of situational

prevention, therefore, is rule setting - the introduction of

new rules or procedures (and the clarification of those

already in place) to remove any ambiguity concerning the

acceptability of conduct. For example, in attempting to

reduce "no-shows," many restaurants will now only

accept reservations if callers leave a telephone number

where they can be reached. Some also require a credit

card number so that a charge can then be made for noshows. Requiring anglers in California to wear their

fishing licenses was successful in getting more of them to

comply with license purchase rules.

Post instructions. Work rules are often set out in

employment contracts, and rules established by credit card

companies, telephone providers, and insurance companies

are contained in the service contracts. Regulations

governing public places or facilities may be publicly

posted, either to prevent people claiming ignorance of the

rules or to show precisely where these apply. The roads, in

particular, make extensive use of signs governing driving

or parking. Studies have found that warning signs

significantly reduce illegal parking in spaces reserved for

disabled drivers. Many other facilities - parks, colleges,

transit lines and housing projects - also post signs to

govern a wide range of behaviors. Despite their wide use,

there have been few evaluations of the preventive

effectiveness of posted instructions - but they are an

essential tool of law enforcement and are often used in

problem-solving efforts.

Alert conscience. This situational technique differs from

"informal social control" in two important respects. First,

the focus is on specific forms of crime occurring in

discrete, highly limited settings and, second, the purpose

is to alert conscience at the point of committing a specific

kind of offense rather than attempting to bring about

lasting changes in generalized attitudes to law breaking.

For example, signs at store entrances announce

"Shoplifting is stealing," and in Manhattan's Port

Authority Bus Terminal signs proclaim "Smoking here is

illegal, selfish and rude." Roadside speed-boards give

immediate feedback (without issuing fines) to motorists

traveling above the speed limit.

Assist compliance. When Italian criminologist Cesare

Lombroso suggested in the 19th century that people

should be locked up for urinating in the streets, his pupil

Enrico Ferri suggested a more practical way to solve the

problem: build public toilets. This constitutes an example

of facilitating compliance, a technique of wide application.

It includes subsidizing taxi rides for those who have been

drinking, providing litter baskets and "graffiti boards" (for

people's public messages), and improving checkout

procedures in libraries, which reduce delay and thus

excuses for failing to comply with rules for book

borrowing. In a classic paper on Disney World, Shearing

and Stenning provide a fascinating glimpse into the ways

in which sophisticated crowd control and management -

involving the use of pavement markings, signs, physical

barriers (which make it difficult to take a wrong turn) and

instructions from cheerful Disney employees - greatly

reduce the potential for crime and incivility in the theme

park (see box).

Control drugs and alcohol. Crime is facilitated by

alcohol and drugs, which undermine inhibitions or impair

perception and cognition so that offenders are less aware

of breaking the law. The value of situational controls on

drinking has often been demonstrated. Johannes

Knutsson, research director at the Norwegian Police

College, has shown that limiting the amount of alcohol

that individuals could bring into a Swedish resort town on

Midsummer Eve helped to reduce drunkenness and

disorderly conduct. The small community of Barrow,

Alaska, instituted a total ban in 1994 on the sale of

alcohol to curb binge drinking, which led to an 81 percent

drop in alcohol-related calls for service, a reduction of 43

percent in felonies, and drop of more than 90 percent in

4343. Remove excuses for crime
Crime Analysis for Problem Solvers in 60 Small Steps

removals of drunken people from public places (see

Goldstein Award submission at www.popcenter.org).

Voluntary agreements reached among local drinking

establishments to promote responsible drinking have

reduced alcohol-related crime in numerous nightlife areas

in Australia. Rutgers University has decreed that beer

must be served from kegs instead of cases at dorm parties

because cases are easier to hide and, as one student said:

"If you have one keg and a line of 20 people behind it,

people will get less alcohol than if you had a refrigerator

and people were throwing out beer."

FIND A PRACTICAL RESPONSE

Set rules

• Rental agreements 

• Harassment codes

• Hotel registration

Post instructions

• "No Parking"

• "Private Property"

• "Extinguish camp fires"

Alert conscience

• Roadside speed display boards

• Signatures for customs declarations

• "Shoplifting is stealing"

Assist compliance

• Easy library checkout

• Public lavatories

• Litter bins

Control drugs and alcohol

• Blood alcohol self-testing in bars

• Server intervention

• Alcohol-free events

• Signs tell visitors arriving by car to tune into Disney radio for information.

• Signs direct them to the parking lot they must use and road markings show the way.

• Smiling parking attendants direct visitors to their space and loudspeakers remind them to lock their cars.

• Visitors are directed to rubber-wheeled trains to take them to the monorail.

• Recorded announcements direct them to stand safely behind guardrails.

• They are reminded about the location of their parking space (e.g., Donald Duck 1).

• They are (politely) asked to sit, to keep their arms and legs within the confines of the carriage, and to make sure

children do the same.

• Before disembarking, they are told how to get to the monorail and barriers stop them from going the wrong way.

• On the platform, attendants guide them into corrals the right size to fill one compartment of the monorail.

• Safety gates at the platform edge open only when the monorail arrives.

• Any delays in service are announced and expected times of arrival are given.

• On board, passengers are asked to remain seated "for your own safety".

• Passengers are told how to disembark and how to move to the first entertainment.

• They are once again reminded to look after their children and to take their possessions.

• While waiting to enter each exhibit, visitors are marshaled in lines, which indicate waiting times; those in line are

entertained by Disney characters.

• On leaving the exhibit, they are guided by signs, barriers and attendants to the next one.

Remove Excuses

Arriving at Disney World

Source: Shearing, Clifford and Phillip Stenning (1997). "From the Panopticon to Disney World: The Development of

Discipline". Situational Crime Prevention: Successful Case Studies (2nd ed.), Ronald V. Clarke. Monsey, NY: Criminal

Justice Press.
Many problems arise through the failure of some

institution - business, government agency, or

other organization - to conduct its affairs in ways

that prevent crime rather than cause it. In short, many

problems occur because one or more institutions are

unable or unwilling to undertake a preventive strategy, or

because these institutions have intentionally established a

circumstance that stimulates crimes or disorder. This

creates risky facilities (Step 28) and other concentrations

of crime.

Solving problems usually requires the active cooperation

of the people and institutions that have failed to take

responsibility for the conditions that lead to the problem.

These problem owners have shifted responsibility for the

problem from their shoulders to the shoulders of the

public and the police. Consequently, an important

objective of any problem-solving process is to get them to

assume responsibility. So for any problem, you need to

answer three ownership questions:

• Who owns the problem?

• Why has the owner allowed the problem to develop?

• What is required to get the owner to undertake

prevention?

Who owns the problem? When a problem is located at

a specific place, it is usually easy to identify who is

responsible. The owner of the problem is the owner of the

location. A problem in a park, for example, is the body

with the responsibility for operating the park - usually a

local government or some private agency.

It is more difficult to identify those responsible for

problems that are spread over larger areas. If a

widespread problem is focused on a specific location, then

that location may be the source for the events in the

surrounding area, and the owner of the central location

may be responsible. A real estate speculator, who owns

many derelict properties in a neighborhood, owns the

crime associated with these properties.

If there is a special group of individuals - the elderly,

children with special needs, or victims of domestic

violence - and these individuals are targets of crime or

disorder, then potential owners of the problem are family

members. If there are agencies charged with seeing to

the well-being of these special groups, these service

agencies are possible co-owners of the problems. While

trying to reduce the highway deaths of migrant workers,

the California Highway Patrol identified businesses that

specialized in the transportation of migrant workers. They

owned the problem but were not being responsible.

Fixing responsibility entailed stepped up regulation of

these businesses, including vehicle inspections, requiring

seats and seat belts for certain types of migrant transport

vehicles, and greater enforcement of safety violations. The

result was a large reduction in fatal accidents involving

migrant farm workers. This effort received the Goldstein

Award for Problem-Solving Excellence in 2002.

Why has the owner allowed the problem to

develop? There are four generic explanations that alone

or in combination fit most problems:

1. An institution may be unable to prevent crime. This

might be due to ignorance as to the effect of its

operations on crime or ignorance as to how to prevent

crime. Or this may be due to lack of resources, even

when the institution knows its operations help create

crime. It is also important to recognize the importance

of institutionalized procedures. Changing procedures

can be time consuming and costly in both monetary

resources and staffing. A new inventory control

procedure to prevent shoplifting and internal theft may

be difficult to implement because it requires disruptive

changes in the ways employees conduct their 

normal business.

2. Some institutions may be unwilling to prevent crime

facilitated by their operations because they believe that

fixing crime is the exclusive responsibility of the police

(e.g., gas stations with a high rate of gasoline drive-offs

may see gas thieves as the problem rather than their

lack of a pre-pay policy). Rather than recognize the role

of opportunity in creating crime, some people dwell

exclusively on the role of offenders. From this

perspective, it is the function of police to reduce crime

by stricter enforcement. The limitations of this approach

have been noted in Step 3. Another source of

unwillingness is the belief that the police are intruding

on the property owner's rights. A retailer might claim

that he has the right to display goods any way he

wants, and that the police should not compel, or even

suggest, alternative displays that might 

reduce shoplifting.

4444. Find the owner of the problem
Least cooperative/ Most difficult

Most cooperative/ Least difficult

Crime Analysis for Problem Solvers in 60 Small Steps

3. Some institutions are unwilling because of the costs of

addressing the problem; they gain more by ignoring

crime than they lose. They may perceive that the costs of

prevention outweigh any benefits to them. Security

personnel at an entertainment venue are costly, and

quality security personnel are more costly. If the costs of

the problem are not borne by the facility, then there is

little perceived need to bear the costs of prevention. In

essence, such facilities are exporting the costs of crime

and prevention onto others, and thereby reducing their

own costs.

4. Some institutions may profit from the crimes, as can

happen when a used goods shop does little to verify

legitimate ownership of the merchandise they display.

Auto repair garages can purchase stolen car parts

cheaper than legal car parts, thus increasing their profit

margin.

What is required to get the owner to undertake

prevention? Herman Goldstein has outlined a rough

hierarchy of interventions designed to shift responsibility

for problems from the police back to the institutions that

own them (see box).

Moving from the bottom to the top of Goldstein's list,

interventions become less cooperative and increasingly

coercive. Because of this, the difficulty of intervention

increases, along with the costs of failure to the police, as

one moves up the list. Consequently, the value of

information and thorough analysis increases from the

bottom to the top. As Goldstein notes, this hierarchy is a

rough indicator of these trends rather than an exact

description. Nevertheless, it is useful for planning a

layered set of responses to a problem - beginning with

the most cooperative and working upward only if needed

and only when supported by information.

Shifting responsibility back to the owner of the problem

can create legal and political conflicts. Institutions that

had gained from the problem, or foresee a cost in taking

responsibility for it, are unlikely to simply agree to a

suggestion that they do something about it. The problem

of false alarms has been a plague for over two decades,

but in many jurisdictions it is difficult to overcome the

political and financial clout of the alarm industry who are

principally responsible for the high level of false alarms.

Clearly, the least costly and intrusive prevention measures

will meet the least resistance (Step 45). But if these

responses turn out to be ineffective, then the police often

face a difficult choice: demand greater responsibility from

problem owners and risk a political conflict, or continue to

spend the public's money on a problem created by a few

individuals. In the abstract the answer seems clear, but in

practice it is often a difficult decision.

Read More:

Scott, Michael (2005). "Policing for Prevention: Shifting

and Sharing the Responsibility to Address Public Safety

Problems." Handbook of Crime Prevention and

Community Safety, Nick Tilley. Cullompton U.K.: Willan.

FIND A PRACTICAL RESPONSE

Herman Goldstein's Hierarchy of Ways to Shift Ownership

Bringing a Civil Action

Legislation Mandating Adoption of Prevention

Charging a Fee for Police Service

Withdrawing Police Service

Public Shaming

Creation of a New Organization to Assume Ownership

Engaging Another Existing Organization

Targeted Confrontational Requests

Straightforward Informal Requests

Educational Programs
F

inding a suitable response can be a troublesome

process. You may be repeatedly disappointed when

promising interventions are vetoed because of

expense or difficulty, or because of lack of cooperation.

But there is more than one way to solve a problem. So,

eventually your team will agree on a response that meets

some basic requirements:

• It is not too ambitious or costly.

• It focuses on near, direct causes rather than on distant,

more indirect ones, which gives it a good chance of

making an immediate impact.

• The mechanism through which each response should

impact the problem has been clearly articulated.

So, at last your worries are over and you can relax, right?

Wrong! Even more difficult than agreeing on a good

response is to make sure that it is actually implemented.

You cannot ensure this on your own, but if you know the

pitfalls of implementation, you can steer the partnership

away from choosing responses that can fall prey to these.

Tim Hope and Dan Murphy identified these pitfalls when

studying a vandalism prevention project in eleven schools

in Manchester, England.

The responses to be implemented at each school were

selected by groups of local government officials, school

staff and police. Much of the damage was more careless

than malicious. This suggested two different solutions:

situational responses to protect the buildings or providing

recreational activities to divert children into less harmful

activities. Only one of the eleven groups recommended

improved leisure provision. The situational responses

recommended were mostly basic target-hardening

(window grills, toughened glass and high fences), though

proposals also included a plan to encourage local

residents to keep an eye on two adjacent schools and a

plan to move a playground to a less vulnerable area.

At only two schools were all the recommendations

implemented. In three, none was put in place and at the

remaining six schools one or more recommendations

failed to materialize. These failures to implement meant

there was little impact on vandalism. Hope and Murphy

identified five main obstacles to implementation, all of

which have been encountered in U.S. problem-solving

projects:

1. Unanticipated technical difficulties. For eight

schools, the groups recommended the replacement of

vulnerable windows with polycarbonate glazing or

toughened glass. However, not a single pane of either

type was installed. The city architects had prohibited

polycarbonate glazing because in case of fire it would

prevent escape and might give off toxic fumes.

Toughened glass had to be cut to size before it was

toughened, but the panes came in many sizes and it

would have been difficult to store a few of each size

in readiness. The alternative of supplying a pane to

order was ruled out by the long time (six weeks) it

would take to do this.

2. Inadequate supervision of implementation. At

one school it was agreed to move the playground to

a less vulnerable area. The original playground was to

be replaced with flowerbeds, but this had to be done

by a government agency that got no further than

providing an estimate for the work. The relocation of

the playground was sub-contracted to a private

builder, but due to a misunderstanding only half the

proposed area was resurfaced. After two years, therefore, vandalism was unchanged, there were no

flowerbeds, and the school had acquired a useless,

narrow strip of pavement.

3. Failure to coordinate action among different

agencies. Every recommendation that was the sole

responsibility of the buildings maintenance section of

the school system was implemented, while none of

those involving other departments or agencies ever

materialized. For example, it was recommended that

people living near two schools should be encouraged

to keep an eye on them after hours and report anything suspicious to the police. This required the

cooperation of the school system administration, the

principal, staff and pupils of the schools and three

branches of the police - crime prevention, community

relations and local police. All liked the idea, but no

one would take the lead.

4. Competing priorities. During the implementation

period many other demands were placed on the

school system as a result of widespread labor unrest

by local government employees and a school

reorganization made necessary by a declining schoolage population. School staffing changes resulted in

the reassignment of staff who were involved in the

vandalism project. It is not surprising that the staff

gave the vandalism project low priority.

4545. Choose responses likely to be implemented
Crime Analysis for Problem Solvers in 60 Small Steps

5. Unanticipated costs. In some cases, the wider

consequences of a particular course of action

outweighed its immediate benefits. For example, at

the school with the most serious vandalism problem it

was decided to mount a security patrol for the

upcoming holiday period. The school maintenance

workers were employed to patrol the school for

payment during their spare time. This was

immediately successful in reducing vandalism and was

extended beyond school holidays to provide coverage

at evenings and weekends. Other schools demanded

the same protection and more maintenance workers

wanted the additional overtime opportunities.

Ultimately the cost became too high and the project

was scrapped.

You can see from the list above that some

implementation problems cannot be anticipated and that

a proportion of all responses selected will never be

implemented. However, it is also clear that certain kinds

of responses can be expected to encounter problems and

these are summarized in the box. In some cases, of

course, a response may be so promising that it is worth

pursuing despite the risks of implementation failure. But

being forewarned is to be forearmed.

Read More:

Hope, Tim and Daniel Murphy (1983). Problems of

Implementing Crime Prevention: The Experience of a

Demonstration Project. The Howard Journal, XXII, 38-50.

Laycock, Gloria and Nick Tilley (1995). Implementing

Crime Prevention. In Building a Safer Society, edited by

Michael Tonry and David Farrington University of 

Chicago Press.

FIND A PRACTICAL RESPONSE

• Requires coordinated action among a number of separate agencies.

• Will take a long time to introduce and involves a number of steps to be completed in sequence.

• Must be implemented by staff with little understanding of its purpose.

• Has no major supporter among the partnership team.

• Lacks the support of senior administrators.

Expect implementation problems when a response:

• That is outside the partnership.

• That is poorly resourced or in turmoil.

• That will gain little direct benefit from the solution.

Also expect problems when the response must be implemented by an agency:
T

he first critical step in assessment is to conduct a

process evaluation. It answers the question,"Was the

intervention put into place as planned and how was it

altered for implementation?" As shown in the figure, a

process evaluation focuses on the resources that were

employed by the response (inputs) and the activities

accomplished with these resources (results), but it does not

examine whether the response was effective at reducing

the problem (outcomes). For that you need an impact

evaluation. An impact evaluation tells you whether the

problem changed (Steps 47 to 53).

ROLES OF PROCESS AND IMPACT EVALUATIONS

Both types of evaluations are needed in a POP project. The

table summarizes possible conclusions based on the

findings of both types of evaluation. A) The response was

implemented in accordance with the plans, and there are

no other reasonable explanations for the decline. So there

is credible evidence that the response caused the reduction.

B) The response was implemented as planned, but there

was no reduction in the problem. So there is credible

evidence that the response was ineffective.

But what if the response was not implemented as planned?

In this case, it is hard to come to a useful conclusion. C) If

the problem declined, it might mean that the response was

accidentally effective or some other factor was responsible.

D) If the problem did not decline, then no useful conclusion

is possible. Perhaps the implemented response is faulty and

the original response would have been effective, or neither

is effective. Unless the planned response was implemented,

it is hard to learn from an impact evaluation.

4646. Conduct a process evaluation

Focus of Process and Impact Evaluations

Response implemented

as planned

A. Evidence that the

response caused 

the decline

B. Evidence that the

response was ineffective

Response not implemented as

planned

C. Suggests that the response was

accidentally effective or that other

factors may have caused the decline

D. Little is learned

Problem declined

and no other likely

cause

Problem did 

not decline

Impact

Evaluation

Results 

Process Evaluation Results

Interpreting Results of Process and Impact Evaluations

INPUTS

• personnel

• equipment

• expenditures

• other resources

RESULTS

• arrests

• people trained

• barriers installed

• other tasks accomplished

OUTCOMES

• crimes reduced

• fear abated

• accidents reduced

• other reductions in problems

Process evaluation focus

Impact evaluation focus
Crime Analysis for Problem Solvers in 60 Small Steps

A response is a complex piece of machinery with a variety

of components, any of which can go wrong (Step 45). A

process evaluation examines which components were

carried out successfully. The process evaluation checklist

highlights the questions that you should ask.

Scheduling of activities in a problem response is often

critical. For this reason, it is useful to create a project

timeline showing when key components were

implemented. It is also useful to show when other

unexpected events occurred and noting publicity so you

can check for Anticipatory Benefits (Step 52).

Though unexpected developments can force you to modify

a response, some of these developments can be

anticipated by understanding what can go wrong with

responses. Some of the possible answers are as follows:

1. You may have an inadequate understanding of

the problem. You may have focused too little on

repeat victims, for example. This can be caused by

invalid assumptions about the problem or insufficient

analysis (you did not look for repeat victimization, for

example). If, while developing the response, you can

identify weak spots in your analysis, then you can

create contingency plans (a plan to address repeat

victimization should this prove to be needed).

2. Components of the project have failed. The

process evaluation checklist shows that there are

many potential points of failure. However, not all

components are equally important for success.

Further, it is sometimes possible to anticipate

components with high failure rates. Citizen groups in

general are quite variable in their ability to carry out

tasks, for example. Building in redundancy or

formulating backup plans can mitigate 

component failure.

3. Offenders may react negatively to your

response (Step 11). Some forms of negative

adaptation can be anticipated and planned for.

Sometimes geographical displacement locations can

be identified before the response, for example, and

advanced protective actions can be taken to

immunize them.

4. There are unexpected external changes that

have an impact on the response. A partner

agency's budget may be unexpectedly cut, for

example, forcing it to curtail its efforts on the

problem. As the problem will not dissipate on its own,

the only recourse is to alter the plans.

Process evaluations require information. This information

will come largely from members of the problem-solving

team, so it is important that they document their

activities. Which activities they document and who

records it in what detail are questions that should be

resolved while planning the response.

ASSESS THE IMPACT

Who is supposed to act? 

Police units Government partners Community groups Businesses Others 

What are they supposed to do? _______

Do they have the capability to act?

Legal authority Local authority Resources Expertise 

When were they supposed to act? 

Date and times_____ Coordination with others _____

Who or what is supposed to receive action? 

People_____ Places_____

Was the action delivered appropriately? 

Type _____ Intensity_____ Duration_____

Are there back up plans for . . .

Faulty plans ? Component failure ? Adaptation ? External changes ?

A Process Evaluation Checklist
Y

ou should address three questions when assessing

a response:

1. "What was the implemented response?" A process

evaluation answers this question (Step 46).

2. "Did the problem decline?" Comparing the level of the

problem after the response to the level of the problem

before answers this question.

3. If the response declined, then ask "Did the response

cause this decline, or was it something else?" There are

usually many alternative explanations for the decline in

the problem.

Answering the third question requires the use of controls.

The purpose of controls is to rule out alternative

explanations. Different alternative explanations require

different types of controls as described below:

Changes in size. If there had been a decline in the

number of tenants in an apartment building, we would

expect the number of burglaries to decline because there

are fewer potential victims. A reduction in targets is an

alternative to the explanation that the drop was due to

the intervention. To control for changes in size, divide the

number of burglaries before and after the response by the

number of occupied apartments before and after the

response. In the table, what appears to have been a

decline in burglaries was partially caused by the drop in

occupied units. When this is accounted for, we still notice

a response effect. If the time periods before and after are

of substantially different lengths, we control for this by

dividing again by the number of months before and the

number of months after to get burglaries per occupied

unit per month.

Cycles of activity. Human activity oscillates over days,

weeks, and months. Some of the most common cycles

include commuting and attendance at school, work, and

leisure, and seasons and holidays. Such cycles cause

regular changes in problems. To control for cycles,

compare the same part of the cycle before the response to

the same part of the cycle after the response.

Long-term trends in the problem. Problems may be

getting worse (or better) before the response (Step 26).

Without accounting for trends one could conclude that

the response was responsible, when in fact this might

have occurred anyway. There are two ways of controlling

for trend. The first method is to measure the problem for a

long period before the response so that any trend can be

identified. Substantial deviations from the existing trend

after the response are evidence of a response effect.

Anticipatory effects (Step 52) are drops in the problem

due to the response, but occurring before the response is

fully implemented. These need to be distinguished from

longer trends prior to implementation.

The second method is to compare the people or places

getting the response to a similar group of people or

places not getting the response. This is called a control

group or a comparison group. A control group must be

similar to the response group with regard to the problem,

but cannot receive the response. A control group tells you

what would have happened to the response group, if the

response group had not received the intervention. If the

response group changes differently from the control

group, this is evidence of a response effect.

Other unexpected events. Many other things are

changing as the response is implemented, one or more of

which could have caused the decline in the problem.

Instead of an accident-reduction response causing a

decline in accidents on a road, for example, slow traffic

from the road repairs, going on about the same time as

the response, might have been the cause. The standard

approach is to use a control group, as we discussed for

examining trends. The control area is only useful if it is

affected by the same factors as the response area. So,

counting accidents on the response and control roads,

both of which are influenced by the road repairs, could

tell you whether the road repairs contributed to the

decline in accidents.

Change in problem measurement. A before-after

comparison is only valid if the problem was measured in

the same way before and after the response.

Measurement differences can cause a perceived change in

the problem. Use the same measurement procedures

before and after. Before and after observations should

occur at the same sites at the same times, watch the

same things, and record things in the same way. Before

and after photographs and videos should be taken in the

same light from the same angles, at the same distance,

and with the same size image area. Interviewers should

47

Burglaries

Occupied Units

Burglaries/

Occupied Unit

6 Months

Before

41

83

.494

6 Months After

20

73

.286

Change

-21

-10

-.208

47. Know how to use controls

Using Rates to Control For Changes in Size
Crime Analysis for Problem Solvers in 60 Small Steps

be the same before and after, asking the same questions,

in the same order. Examine official records to determine if

recording practices are stable over time.

Natural decline from an extreme high. Many

problems are addressed because things have become

extremely bad. So the response is implemented when the

problem is abnormally high. But even a relatively stable

problem will fluctuate. A problem that is now abnormally

bad will return to its normal level, even if nothing is done

(this is called "regression to the mean," and it applies to

abnormal lows as well). Comparison area controls may

not be useful here, if the response area is at a peak and

the control area is not. Instead, examine the long-term

fluctuation prior to the response to see if the problem was

abnormally bad.

The figure illustrates some of the uses of controls. Moving

clockwise around this figure, panel A shows a 24-month

time series with a response implemented in early

November of the first year. There is a pronounced yearly

cycle and a downward trend that are not due to the

response. The spike in November following the response

suggests that it backfired.

Panel B shows a before-and-after comparison (the

average of August-October, 2003 compared to the

average of November 2003-January 2004) that suggests a

worsening of the problem following the response.

In panel C, a comparison area has been added. The

immediate before-and-after comparison shows the

response area doing better than its comparison area, but

because of cyclical effects we would not have much

confidence in these findings. Comparing the 3 months

before the response to the same three months a year later

accounts for the cyclical behavior of the crime series.

But because some of the decline in both groups maybe

due to the general downward trend, panel D provides a

better picture of the impact of the response. Before the

response, the area being treated is consistently worse

than the comparison area. After the response, both do

about the same. Also, the troublesome November spike

seems to be unrelated to the response because it shows

up in the control trend, too. The response seems effective,

but is not dramatic, so its improvements were easily

hidden by factors that need to be controlled - trends,

cycles, and unexpected events.

ASSESS THE IMPACT

Some Applications of Controls

50

40

30

20

10

0

Jan. 02

June 02

Dec. 02

June. 03

Dec. 03

23.0

25.3

Aug-Oct, 02 Nov.02-Jan 30

Response begins

Response begins

50

40

30

20

10

0

Response

Control

D. Monthly Time Series for Response and Control Areas C. Before 3 Month Average to Same After 3 Month

Average

Aug-Oct, 02 Nov.02-Jan 30 Aug-Oct, 03

5.7

8.3

22.3

25.3

23.0

16.3

A. Monthly Time Series for Response Area B. Before 3 Month Average to After 3 Month Average

Response

Control

Jan. 02

June 02

Dec. 02

June. 03

Dec. 03
Geographical displacement occurs when the

intervention blocks crime or disorder opportunities

at a facility or in an area, and offenders move to

other facilities or areas to offend. Temporal displacement

also stems from successful prevention, but in this case

offenders shift offending in time to other hours or days.

Offenders can find it difficult to move to some other

location because easy crime or disorder opportunities are

limited (Step 16). Targets may be concentrated at some

places and not others (Step 16). Vulnerable potential

victims can be found at some locations, but not others

(Step 29). Some facilities have low behavioral controls, but

others do not (Step 28). Opportunities that exist are either

already hot spots or are hidden from offenders - either far

away or not recognizable as fruitful places to offend.

Offenders will not usually spend time searching far from

their hot spot when it is suppressed. So, if offenders

move, they are most likely to move to a place close to the

original hot spot. The likelihood that offenders will move

to an opportunity declines the further the opportunity is

from the original hot spot, as illustrated in the figure. Also,

not all spaces are suitable to offenders. Opportunities are

not spread evenly across the map.

In this map, the diamonds are places with characteristics

like the original hot spot. Those closest to the original

location are most likely to be affected most by

displacement. In addition to distance, natural barriers to

movement can limit displacement. In the figure, the river

flowing northeast/southwest reduces the chances of 

displacement to the east. Knowing this, displacement

countermeasures can be applied with the response at the

most vulnerable locations.

If geographical or temporal displacement occurs, it is most

likely to shift crime to locations and times very similar to

the locations and times affected by the prevention. Such

shifts require less effort, learning, and risk for offenders

than shifting to very different places and times. It is more

likely that offenders will try to outwait the response,

which explains Lawrence Sherman's finding that the

effects of crackdowns decay. If offenders cannot outwait a

response, it will be the most familiar locations and times

that will have the greatest chance of receiving displaced

crime. As Paul and Patricia Brantingham note, it is possible

to predict the most likely areas for displacement. But this

requires detailed knowledge of the crime opportunities in

the current situation.

If geographical displacement occurs, it can distort

conclusions about effectiveness. Table 1 illustrates how

this can happen. In this example there are three similar

areas with equal numbers of crimes before treatment: (1)

a treatment area; (2) an area adjacent to the treatment

area; and (3) an area distant from the treatment area. The

treated area has a decline of 25 crimes. However, the

adjacent area has a 10-crime increase. This seems to

suggest that if nothing had been done in the treatment

area it too would have experienced a 10-crime increase.

So the net reduction is 35 (the 25 crimes reduced in the

treatment area and the 10-crime increase that 

was averted).

4848. Consider geographical and temporal displacement

Decline of Geographical Displacement with Distance from Hot Spot Epicenter
Crime Analysis for Problem Solvers in 60 Small Steps

But these extra 10 crimes could have been due to

geographical displacement. One would be better off using

the distant control area for comparison. As a control, the

distant area suggests that if no treatment were

implemented, crime would not have changed in either the

treatment or the adjacent areas. The implication is that

the treatment caused a 25-crime decline in the treatment

area, but a 10-crime increase in the adjacent area

(displacement), for a combined reduction of 15 crimes.

Though effective, the program is not as effective as

originally estimated. Step 51 describes formulas to take

account of displacement when assessing effectiveness.

Try to select two comparison areas as part of evaluations:

one near the treatment area that has similar crime

opportunities to detect geographical displacement (and

diffusion, Step 51), and the other to serve as a control

area. The control area should be protected from

displacement contamination by distance or some other

barrier (e.g., a highway or river). Valid selection of control

and displacement areas requires you to have some idea of

offenders' normal movement patterns, as the control area

needs to be outside their roaming territory while the

displacement area should be within it.

Temporal displacement may be easier for offenders than

geographical displacement because it requires less effort.

Temporal displacement can occur within a 24-hour day, if,

for example, the prevention is restricted to certain times

but leaves other times unprotected. It can also occur over

a week. Or it can occur over longer periods.

If the evaluation compares times with a prevention

response to times without a prevention response,

contamination of temporal controls can take place. In

Table 2, a treatment takes place on Saturday and Sunday.

The average number of crimes on these days dropped by

25 crimes after treatment, while crimes on Mondays and

Fridays increased by 10. Was this due to temporal

displacement? Midweek days may be more valid controls

because they have less in common with weekends than

do Mondays and Fridays.

Waiting out the prevention is a common form of temporal

displacement. Enforcement crackdowns are particularly

vulnerable to this form of time shifting because they are

temporary by definition. If an intervention can be

maintained (unlike a crackdown), then offenders cannot

wait it out. They then face the difficult option of moving

to less attractive places or targets or undertaking new

tactics or other crimes. If these options are too difficult,

unrewarding, risky, or otherwise unattractive they may

commit fewer offenses.

Read More:

Brantingham, Paul and Patricia Brantingham. (2003).

"Anticipating the Displacement of Crime Using the

Principles of Environmental Criminology." Crime

Prevention Studies, volume 16. Monsey, NY: Criminal

Justice Press.

Eck, John (2002). Assessing Responses to Problems: An

Introductory Guide for Police Problem-Solvers.

Washington, DC: U.S. Department of Justice, Office of

Community Oriented Policing Services. (Accessible at:

www.popcenter.org and www.cops.usdoj.gov ).

ASSESS THE IMPACT

Treatment

Adjacent Area

Distant Area

Before

100

100

100

After 

75

110

100

Difference

-25

+10

0

Estimated Net effect

-35

-25

Table 1: Use of Adjacent and Distant Control Areas in Controlling for 

Geographical Displacement

Treatment

Adjacent Area

Distant Area

Days of week

Sat & Sun

Mon & Fri

Tues-Thurs

Before

100

100

100

After

75

110

100

Difference

-25

+10

0

Estimated

Net effect 

-35

-25

Table 2: Using Days of the Week to Control for Temporal Displacement
I

n addition to geographical and temporal displacement,

offenders can switch targets, change their tactics, or

change crimes.

Target displacement involves offenders shifting from newly

protected targets to other targets. In 1970, when steering

column locks became required in all new cars sold in

Britain, thefts of new cars dropped from 20.9 percent of

all cars stolen in 1969, to 5.1 percent in 1973. However,

the overall theft rate of automobiles stayed roughly

constant because offenders switched from the newer,

protected, vehicles to older, unprotected, vehicles. This is

one of the few documented cases where displacement

wiped out most prevention gains, at least in the short run.

Over a longer period, these devices appeared to have

curbed theft for temporary use. As this case illustrates, it is

easy for offenders to switch to very similar targets. Target

displacement is less likely when the alternative targets are

unlike the old targets.

Step 42 shows how geographical or temporal

displacement can contaminate control groups. If the

evaluation of a prevention effort uses a target control

group, then a similar form of contamination can take

place. Imagine a response to curb theft of purses from

women over 60 years old in a shopping center. To

estimate what the trend in elderly purse theft would be if

nothing had been done, the theft of purses from middleaged women of 45 to 59 is measured. If, unknown to us,

the thieves displaced from the protected older women to

unprotected middle-aged women, we would conclude that

purse theft would have gone up without a response.

When we compare this control target group change to the

treatment group change we would mistakenly inflate the

treatment effectiveness. A better control group might be

even younger women shoppers (ages 30 to 44, for

example), or even better, wallet theft of male shoppers.

Though neither of these alternatives is perfect, they are

improvements because one would expect far less

displacement to dissimilar targets. Or, select another

shopping district as a control area - in which case you

would have to guard against geographical diffusion or

displacement contamination, Steps 48 and 51.

Tactical displacement occurs when offenders change their

tactics or procedures. They might use different tools to

defeat better locks, for example. Or computer hackers

might alter their programs to circumvent improved

security. In medicine, some bacteria can mutate quickly so

a drug that is effective against one form of the bacteria

becomes less effective as mutant strains become more

prevalent. One way of countering this is to use broadspectrum treatments that are effective against a wide

range of mutations. Similarly, "broad spectrum" responses

protect against existing methods used by offenders and

many modifications of these tactics. Broad-spectrum

interventions require offenders to make big changes in

their behavior that they may not be able to do. Paul

Ekblom describes attempted tactical displacement

following the installation of barriers in British post offices

to prevent "over-the-counter" robberies; some offenders

tried using sledge-hammers. This change in tactics was

not particularly successful, however, and displacement was

limited. These barriers are an example of a 

broad-spectrum intervention as they were able to defeat 

new tactics.

Switching crime type is another type of displacement you

should look for. Offenders might switch from vehicle theft

to vehicle break-ins, or carjacking. We sometimes

evaluate responses to one type of crime by comparing the

trend in a similar type of crime that did not get a

prevention response. For example, we might select theft

from vehicles as a control in the evaluation of a theft of

vehicles intervention.

The same principles of contamination and protection

apply to tactical and crime type displacement as we found

with other forms of displacement. If the tactic or crime

type is very similar to the tactic or crime type being

addressed, then displacement could contaminate these

controls. Dissimilar tactics or crime types are less likely to

suffer contamination. But if they are too dissimilar it is not

a useful control.

There is no perfect solution to this problem and

compromises must be struck. The consequence is that it is

often difficult to know if displacement is occurring and

difficult to judge the effectiveness of the intervention.

Compounding these difficulties is that multiple forms of

displacement can occur simultaneously. Indeed,

sometimes one form of displacement will necessitate

another form as well. Target displacement may require a

change in tactics, and if the new targets are not in the

same places as the old targets, geographical displacement

will occur, too.

4949. Examine displacement to other targets, tactics, and crime types
In Germany (as elsewhere) the enactment of helmet laws was followed by large reductions in thefts of motorcycles.

After the laws were brought into place in 1980, offenders wanting to steal a motorbike had to bring a helmet or

they would be spotted quickly. The figure shows that by 1986 thefts of motorbikes had dropped to about one-third

of their level in 1980, from about 150,000 to about 50,000. (The gradual decline probably reflects stronger

enforcement and growing knowledge about the requirement.) This fact suggests that motorbike theft has a much

larger opportunistic component than anyone would have thought. The existence of excellent theft data in Germany

allowed researchers to investigate whether the drop in motorcycle theft had resulted in target displacement to theft

of cars or bikes, other forms of personal transportation.

The other two lines show the national totals for car and bike thefts during the same years. These provide some

limited evidence of displacement in that thefts of cars increased by nearly 10 percent between 1980 and 1986, from

about 64,000 to 70,000. Thefts of bicycles also increased between 1980 and 1983, but by the end of the period had

declined again to a level below that for 1980. Altogether, it is clear that at most only a small proportion of the

100,000 motorbike thefts saved by the helmet laws were displaced to thefts of other vehicles.

A little thought shows why this may not be surprising. Motorbikes may be particularly attractive to steal. They are

much more fun to ride than bikes for the young men who comprise most of the thieves. Even if the intention is

merely to get home late at night, a motorbike offers significant advantages, especially if the distance is more than a

few miles. Motorbikes may also be easier to steal than cars since the latter have to be broken into before they can

be started. Like bikes, cars also offer less excitement than motorcycles and they may require more knowledge 

to operate.

Crime Analysis for Problem Solvers in 60 Small Steps

You cannot find displacement unless you look for it. This

means that you should examine a problem closely and

imagine the most likely forms of displacement. Are there

other opportunities for crime or disorder that are similar

to the opportunities your efforts are trying to block? Will

your offenders easily discover these opportunities?

Looking for displacement opportunities prior to finalizing

a response gives you two advantages. First, you can

develop measures for detecting it should it appear. More

important, you may be able to develop counter-measures

that prevent displacement.

Read More:

Ekblom, Paul (1987). Preventing Robberies at Sub-Post

Offices: An Evaluation of a Security Initiative. Crime

Prevention Unit Paper 9. London: Home Office.

Webb, Barry (1994). "Steering Column Locks and Motor

Vehicle Theft: Evaluations from Three Countries". Crime

Prevention Studies, volume 2, Ronald Clarke. Monsey, NY:

Criminal Justice Press. (Accessible at: www.popcenter.org).

ASSESS THE IMPACT

A study of target displacement: helmet laws and the reduction in motorcycle theft 

Source: Mayhew, Pat and colleagues (1989). Motorcycle Theft, Helmet Legislation and Displacement. Howard Journal

of Criminal Justice 28:1-8.

500,000

450,000

400,000

350,000

300,000

250,000

200,000

150,000

100,000

50,000

0

Number of Thefts

1980 1981 1982 1983 1984 1985 1986

Motorcyles Cars Bicycles
T

hree principles of this manual are: (1) it takes more

than offenders to create problems; (2) people cannot

offend if there is no opportunity structure to support

this behavior; and (3) altering the opportunity structures

can dramatically reduce problems. It follows that

responses focusing on only removing offenders have

limited effects on problems. After some offenders are

removed, there may be a decline in the problem for a

short time, then either the old offenders return to take

advantage of the opportunities, or new offenders start

taking advantage of them. This is sometimes called

perpetrator displacement. Natural replacement of

offenders can be slow, particularly if the opportunities are

obscure. But if someone discovered the crime

opportunities in the past, others will rediscover them in

the future. And if the old offenders were removed through

imprisonment, some may return to take advantage of the

opportunities upon their release.

New offenders attracted by opportunities might contribute

to long-term crime cycles. Bank robberies in parts of the

United States may be an example of this. For a few years

there will be a large number of these crimes and then

they will decline for several years, only to surge again

later to start the cycle over again. One hypothesis for

these cycles is that during peak robbery years, banks

begin instituting a host of preventive measures and most

offenders are caught and imprisoned. These efforts drive

bank robbery down. After several years with few bank

robberies, bank security becomes lax and the

opportunities for bank robbery increase. Then new

offenders start to take advantage of the lower security,

beginning a new wave of robberies and prevention. This

hypothesis draws attention to the fact that it takes more

than enforcement to be effective, and prevention gains

must be maintained to stay effective.

In fact, it is quite common to read descriptions of

problem-solving efforts that begin with a description of

failed enforcement efforts. In every situation either old

offenders keep coming back or new offenders have

replaced them. There are three ways in which new people

are exposed to offending opportunities:

1. They are exposed to them through their normal daily

routines. Police arrest young men stealing items from

unlocked cars in a city center, for example, but

unlocked cars with things in them remain there. Of

the many people who use the city center on a daily

basis, a few will notice these cars and try their hand

at theft. If successful, some of these individuals will

continue to steal from cars.

2. They are exposed to crime opportunities through

informal networks of friends and acquaintances.

People already experienced in taking advantage of an

opportunity to commit crime or disorder may invite

others in to help them or enjoy the experience. Since

we are seldom 100 percent successful at removing all

the offenders for long periods, there are usually many

people around who can introduce new people to 

the opportunities.

3. They discover offending opportunities through

recruitment. A criminal receiver may employ new

burglars if the old ones can no longer supply him with

goods. If prostitution is organized, then a pimp may

recruit new prostitutes to fill the jobs left vacant by

the former prostitutes. Gangs may bring in new

members to replace old ones. It has been suggested

that adult drug dealers, faced with stiffer penalties for

drug convictions, started hiring juveniles to carry out

the riskiest tasks because the penalties for juveniles

caught with drugs were much less than for adults.

How do you find out if offenders are moving in? The most

straightforward method is to compare the names of

offenders associated with the problem before the

response to the names of offenders associated with the

problem after the response. If the names are different,

then offenders may be moving in. The difficulty with this

approach is that a complete roster of the offenders

involved is seldom available. So it is not clear if the new

names are really new offenders, or if they have been part

of the problem for some time, but have only recently 

been discovered.

Offender interviews can also be helpful. Offenders may

tell you when they became involved in the problem, how

they became involved, and who else is involved. They can

also provide information on tactical and other forms of

displacement. However, offenders can be uncooperative

and unreliable (Step 10).

Sometimes detailed examination of the methods used to

commit crimes can provide insights into whether new

offenders are involved. If the tactics are radically different

than those used earlier, there is a possibility that new

offenders are working. However, it is also possible that

the old offenders have switched tactics.

5050. Watch for other offenders moving in
Crime Analysis for Problem Solvers in 60 Small Steps

Read More:

Matthews, Roger (1997). "Developing More Effective

Strategies for Curbing Prostitution" Situational Crime

Prevention: Successful Case Studies (2nd ed.), Ronald

Clarke. Monsey, NY: Criminal Justice Press.

ASSESS THE IMPACT

Roger Matthews describes a London prostitution problem in the Finsbury Park neighborhood of London. Repeated

crackdowns by the police over many years had failed to control the prostitution market as the prostitutes simply

returned to the same area. When crackdowns were combined with street barriers to make it difficult for men to find

prostitutes by driving around the area in their cars, the level of prostitution activity dropped dramatically. Matthews

suggests that it was the combination of strategies - offender removal through enforcement and opportunity blocking

through street barriers - that was responsible for the decline. One important reason why these interventions were

successful was that the prostitutes were not deeply committed to this way of earning a living. Few of them were

addicts or under the control of pimps. In fact, the most common reasons they gave for working as prostitutes was

that they could earn more money than other forms of work, they enjoyed the independence and enjoyed meeting a

variety of men. Many of them came to Finsbury Park from outlying areas on cheap rail tickets. Together with other

women, they rented rooms in one of the many boarding houses or residential hotels in the area, or they conducted

business in the cars of clients. When not working as prostitutes, many of them worked as barmaids, go-go dancers or

as store clerks. Their relatively light commitment to prostitution and their alternative ways of making money might

help explain why the researchers could find little evidence of displacement of the Finsbury Park prostitutes to other

nearby areas in London.

Combining Crackdowns with Environmental Modifications:

Controlling "Away Day" Prostitutes in Finsbury Park
Y

ou can drastically underestimate the effects of your

intervention if you do not take account of diffusion

of benefits (Step 13). You may conclude that the

intervention is not worth the effort or that it failed to

suppress the problem. This is particularly true when

diffusion contaminates your control group.

Control groups show what would have happened to

problems if you did nothing (Step 47). They need to be as

similar to the treatment group as possible, but they must

not be influenced by the treatment. If prevention diffuses

into the control area, you will get the misleading

impression that things would have gotten better if no

response had occurred. This invalid conclusion will cause

you to underestimate the effectiveness of your program.

(See Step 48 for related issues with displacement.)

Kate Bowers and Shane Johnson suggest two ways to

select control areas when displacement or diffusion of

benefits are possible. The first is to create two concentric

zones around the treatment area. Prevention may diffuse

into the adjacent buffer zone but does not contaminate

the outer control area. This is feasible if the control and

treatment areas are very similar and diffusion or

displacement does not reach the control zone. If these

conditions are not met, then option 2 should be used.

Here a displacement/diffusion sites near the treatment

area are used, but the control areas are widely separated

from the treatment and diffusion/displacement areas.

Controls are selected specifically for their similarity to and

isolation from the treatment area. Multiple control areas

can be selected and their crime rates averaged.

The figure shows an example of option 2. Imagine a

response to the theft from vehicles in downtown Charlotte

parking lots (Step 27). One theft hot spot site is selected

for a response. The neighboring hot spots are good

diffusion/displacement sites. Earlier analysis showed that a

rail line through these lots facilitated the problem, so a

third hot spot lot to the south and west on this rail line is

also a useful diffusion-displacement site. Control lots are

not on the rail line and far enough from the response site

that diffusion and displacement are unlikely.

To determine the overall effect of the response on the

problem (including any diffusion or displacement effects)

you need to answer four questions. Each question has a

simple formula. The letters in the formulas follow 

this pattern.

• R is the number or rate of crimes in the response area.

• D is the number or rate of crimes in the

displacement/diffusion area.

• C is the number or rate of crimes in the control area.

• The subscripts, a and b, indicate when crime is

counted; after or before the response began. For

example, Ra is the rate of crimes in the response area

before the response was implemented, and Cb is the rate

of crimes in the control area after the response 

was implemented.

1. Did the problem change from before to after

the response? Subtract the crime in the treatment

area before the response from the treatment area

after the response to get the Gross Effect (GE):

GE = Rb - Ra

A positive number indicates a decline in the problem.

Zero indicates no change. And a negative number

indicates things got worse.

2. Was the response a likely cause of the change?

Browers and Johnson suggest looking at the difference

in the ratios of the treatment area to the control area

before and after; that is divide the before response by

the before control minus the after response divided by

the after control. This is the Net Effect (NE):

Rb Ra

NE = - . Cb Ca

If the net effect is close to zero, the response probably

was ineffective, and if NE is negative the response may

have made things worse. In either case, displacement

and diffusion are irrelevant so you can stop with the

answer to this question. But if NE is positive, there is

reason to believe the response may have caused the

improvement. This raises the possibilities of diffusion

and displacement. So you need to answer the 

next question.

5151. Be alert to unexpected benefits
3. What is the relative size of the displacement or

diffusion? Bowers and Johnson propose the

Weighted Displacement Quotient (WDQ) to 

measure this:

Da Db

Ca Cb

WDQ = -

Ra Rb

Ca Cb

Da is the crime rate in the diffusion/displacement area

after the program and Db is the crime rate in this area

before the program. The bottom term (denominator)

is a measure of the effectiveness of the response,

relative to the control. An effective program will

produce a negative number in the denominator. The

top term (numerator) shows the relative amount of

diffusion or displacement. The numerator is negative

when diffusion is present and positive when

displacement is present. If it is near zero, neither is

present and the WDQ is zero (so you can skip

question 4). If the WDQ is positive, there is diffusion

(remember, a ratio of two negative numbers is

positive), and if it is greater than one, then the

diffusion effect is greater than the response effect. If

the WDQ is negative, there is displacement. When the

WDQ is between zero and negative one, displacement

erodes some, but not all, of the response effects.

Theoretically, the WDQ could be less than negative

one, indicating the response made things worse.

However, research suggests that this is an 

unlikely occurrence.

4. What is the Total Net Effect of the response

(including diffusion and displacement)? Bowers

and Johnson suggest using the following formula to

calculate the TNE:

C Ca Ca

TNE= Rb -Ra + Db -Da

C Cb Cb

The first part shows the effect of the response in the

response area. The more effective the treatment, the

bigger this term. The second part shows the level of

diffusion or displacement. It will be positive when

there is diffusion and negative when there is

displacement. The more positive the TNE, the more

effective the response.

Read More:

Bowers, Kate and Shane Johnson (2003). "Measuring the

Geographical Displacement and Diffusion of Benefit

Effects of Crime Prevention Activity." Journal of

Quantitative Criminology 19(3):275-301.

Crime Analysis for Problem Solvers in 60 Small Steps

ASSESS THE IMPACT

Lower

Higher

Legend

Parking Areas

1999 LFA by block

Selecting Control and Diffusion/

Displacement Sites

Diffusion/Displacement

Sites

Response Site

Control Sites
Offenders often believe that prevention measures

have been brought into force before they actually

have been started. This leads to what has been

called the "anticipatory benefits" of prevention. Though

these anticipatory effects can occur by accident, the police

can make deliberate efforts to create or intensify them. To

do so successfully, police must have useful insight into

how offenders perceive the situation and have methods

for deceiving offenders as to the true nature of 

the intervention.

Martha Smith and her colleagues found evidence of

anticipatory benefits in 40% of situational prevention

studies whose data could have revealed such benefits.

They have suggested six possible explanations for

observed anticipatory benefits:

1. Preparation-anticipation effects occur when

offenders believe the program is operational before it

is actually working. For example, a property-marking

program may be announced to the public, but

residents have not yet been mobilized, or closed

circuit television cameras may be installed but not 

yet monitored.

2. Publicity/disinformation effects occur when

offenders believe covert enforcement exists as the

result of publicity or rumor. Offenders' perception can

be manipulated, at least in the short run, through

disinformation. Rather than disinformation, targeted

communications can sometimes be effective. A Boston

project to reduce youth homicide used direct

communications with potential offenders to warn

them that certain specified behaviors would result 

in crackdowns.

3. Preparation-disruption effects occur when

preparation for the prevention program causes

surveillance at the prevention sites. Surveys of

residents might alert offenders. Problem-solving

projects can create anticipatory responses during their

analysis stage if there is considerable visible enquiry

in the community. In the late 1980s as part of the

analysis of a burglary problem, members of the

Newport News Police Department conducted door-todoor surveys in a high burglary neighborhood. This

may have contributed to the subsequent fall in

burglaries. In their review of effective policing

strategies, Sherman and Eck noted that door-to-door

police contacts have generally been found to have a

crime reduction effect.

4. Creeping implementation occurs when parts of the

response are put into effect before the official start

date. The evaluator may use June 1st as the beginning

of the full program, but offenders detect staged

implementation in the weeks leading up to June 1,

and change their behavior accordingly.

5. Preparation-training effects occur when planning,

training, and surveys make the public or police better

prepared to address problems and they use this new

knowledge prior to the program going into effect. A

coordinated multi-business anti-shoplifting program,

for example, may be scheduled to begin on a

particular date, but the discussions and training of

employees makes them more attentive prior to 

that date.

6. Motivation of officers or public occurs for similar

reasons as preparation training, except the people

involved are more highly motivated rather than better

equipped. The higher motivation leads to improved

performance in advance of response implementation.

Using a timeline to carefully document when pieces of the

response were implemented is helpful for showing that an

anticipatory effect is plausible (see Step 46).

Smith and her colleagues also identified four distinct

circumstances that masquerade as anticipatory effects, but

are really the results of misinterpretation or 

incomplete analysis:

1. Seasonal changes can create pseudo anticipatory

effects when an intervention begins shortly after a

seasonal turndown in crime. Controlling for

seasonality (Steps 26 and 47) can eliminate 

this problem.

2. Regression effects refer to natural declines in crime

from extreme highs that occur even if nothing is done

(Step 47). If a crime trend for a problem has just

dropped due to a regression effect and a prevention

program is implemented, the natural decline will look

like an anticipatory effect. Examining the long-term

average crime level (Step 26) prior to the response, as

suggested in Step 47, can reveal a regression effect

masquerading as an anticipatory effect.

5252. Expect premature falls in crime
Crime Analysis for Problem Solvers in 60 Small Steps

3. If a crime type (A) has been over-recorded by

changing the classification of another crime, it is

possible to get what looks like an anticipatory effect.

This might occur if one type of crime was inflated in

order to gain funding to address that type of crime,

and then following the receipt of funding, the

classification was changed back to normal. This bogus

anticipatory effect can be detected by looking at

opposite trends in the other crime. Finding two similar

crimes that have opposite trends provides a clue that

classification changes may be responsible.

4. Smoothing data (Step 26) to reveal a trend masked

by random variation can produce results that look like

anticipatory effects. The wider the moving average (5

periods rather than 3, for example) and the bigger

and more abrupt the decline in crime following the

intervention, the more likely smoothing could create a

pseudo anticipatory effect. Comparing smoothed and

unsmoothed data will reveal this pseudo 

anticipatory effect.

Read More:

Sherman, Lawrence and John Eck. 2002. Policing for

Crime Prevention. Pp. 295-329 in Evidence-Based Crime

Prevention, edited by Lawrence Sherman and colleagues.

New York: Routledge.

Smith, Martha and colleagues (2002). Anticipatory

Benefits in Crime Prevention. In Analysis for Crime

Prevention. Crime Prevention Studies, Volume 13. Monsey,

New York: Criminal Justice Press.

ASSESS THE IMPACT

Anticipatory Effects of Publicity

Paul Barclay and colleagues evaluated the effects of bike patrols on auto theft from a large commuter parking lot outside

Vancouver, British Columbia. Vehicle theft dropped after the response, but it had been dropping for several weeks prior to the bike

patrols, since the implementation of a publicity campaign that preceded the bike patrols. In this case, an anticipatory effect may

have added a great deal to the overall effectiveness of the patrols. Though a moving average was used to smooth out random

variation, the drop in thefts between the beginning of the publicity and the beginning of the bike patrols is too large to be due to

data smoothing.

Source: Barclay, Paul and colleagues (1996) "Preventing Auto Theft in Suburban Vancouver Commuter Lots: Effects of a

Bike Patrol." Crime Prevention Studies, volume 6, Monsey, NY: Criminal Justice Press.

25

20

15

10

5

0

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Pubilicity

campaign begins Bike patrol period

Two week periods: Aug. 1 ‘94- Aug. 31, ‘95

Reported Vehicle Thefts
H

ow do you know that a response caused a problem

to decline? Most problems vary in intensity, even

when nothing is done about them. For example, on

average there are 32 vehicle thefts per week in a

particular city center, but seldom are there weeks with

exactly 32 thefts. Instead, 95 percent of the weeks have

between 25 and 38 thefts, and in 5 percent of the weeks

fewer than 25 or more than 38 thefts are recorded. Such

random variation is common. A reduction in vehicle thefts

from an average of 32 per week to an average of 24 per

week might be due to randomness alone, rather than a

response. Think of randomness as unpredictable

fluctuations in crime due to a very large number of small

influences, so even if the police do nothing crime 

will change.

A significance test tells us the chance that a change in

crime is due to randomness. A significant difference is

one that is unlikely to be caused by randomness. It is

harder to discern whether a small difference is significant

than it is to find significance in a large difference. It is

also harder to find a significant difference in a normally

volatile crime problem, even if the response is effective.

And it is harder to find significance if you are only looking

at a few cases (people, places, events, or times) than if

you are looking at many (again, even if the response was

effective.) You cannot control the size of the difference or

the volatility of the problem, but you may be able to

collect data on more cases.

Consider the following common situation. You want to

determine if crime dropped in an area following a

response. You have a number of weeks of crime data

prior to the response and a number of weeks of data for

the same area following the response. You calculate the

average (mean) number of crimes per week for each set

of weeks and find that crime dropped.

The figure shows three possible results. In each panel

there are two distributions, one for the weeks before the

response and one for the weeks after the response. The

vertical bars in each chart show the proportion of weeks

with 0, 1, 2, or more crimes (for example, in the top chart,

6 crimes occurred in 20 percent of the weeks after the

response). In panel A, the distributions barely overlap

because the difference in means is large and the standard

deviations of the two groups are small (see Step 22).

Even with a few weeks of data, a significance test could

rule out randomness as a cause. In panel B, there is

greater overlap in the distributions, there is a smaller

difference in the means, and the standard deviations are

larger. It takes many more cases to detect a non-random

difference in situations like this. In panel C, there is

almost complete overlap, the mean difference is even

smaller, and the standard deviations are even larger. Only

a study with a very large number of cases is likely to find

a significant difference here. The moral is that the less

obvious the crime difference, the more cases you will need

to be sure randomness was not the cause of 

the difference.

5353. Test for significance

0.200

0.150

0.100

0.050

0.000

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

0.120

0.100

0.080

0.060

0.040

0.020

0.000

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

A. Clear Difference

Before Mean=16 Std Dev=2

After Mean=5 Std Dev=2

Number of Crimes

Proportion of of Crimes Proportion of of Crimes

B. Ambiguous Difference

Before Mean=16 Std Dev=4

After Mean=10 Std Dev=4

Number of Crimes
Crime Analysis for Problem Solvers in 60 Small Steps

Probability theory lets us use the mean, standard

deviation, and number of cases to calculate the

probability that randomness is the cause of the difference.

If there is less than a 5 percent chance that the problem's

change was due to random fluctuations, we reject the

explanation of randomness as a cause of the change.

Here, 5 percent is called the significance level. In short,

because the probability that randomness is the cause is

below the significance level (5 percent) we "bet" that

something other than randomness caused the change.

Though 5 percent is a conventional significance level, you

can pick a more stringent level, such as 1 percent. The

more stringent the significance level you select, the

greater the likelihood you will mistakenly conclude that

the response was ineffective when it actually worked.

This type of mistake is called a "false negative" (see Step

37). You might pick a stringent significance level if the

cost of the response is so high that you need to be very

certain it works.

Occasionally, analysts use a less stringent significance

level, such as 10 percent. The less stringent the level you

pick, the greater the possibility that you will mistakenly

endorse a response that has no effect. This type of error is

called a "false positive" (see Step 37). You might want to

pick a less stringent level if the problem is serious, the

measures of the problem are not particularly good, and

you are very concerned about accidentally rejecting a

good response.

There are two ways of using significance levels. In the

discussion above, we used them as rejection thresholds:

below the level you reject random chance and above the

level you accept it as the cause. Always pick the

significance level before you conduct a significance test to

avoid "fiddling" with the figures to get the 

desired outcome.

It is better to use the significance level as a decision aid,

along with other facts (problem seriousness, program

costs, absolute reduction in the problems and so forth), to

make an informed choice. Many sciences, such as

medicine, follow this approach. If you follow this

approach, use a p-value instead of the significance test.

The p-value is an exact probability that the problem's

change is due to chance. So a p-value of 0.062 tells you

that there is about a 6 percent chance of making a falsepositive error by accepting the response. This can be

roughly interpreted to mean that in 100 such decisions,

the decision to reject randomness in favor of the response

will be wrong about six times. Whether you or your

colleagues would take such a bet depends on a 

many things.

It is important to distinguish between significant and

meaningful. "Significant" means that the difference is

unlikely to be due to chance. "Meaningful" means the

difference is big enough to matter. With enough cases,

even a very small difference is significant. But that does

not mean it is worthwhile. Significance can be calculated.

Meaningfulness is an expert judgment.

The investigation of randomness can become very

complex, as there are many different types of significance

tests for many different situations. There are some very

useful websites, as well as books, which can help you to

choose among them, and there are many statistical

software programs that can make the required

calculations. But if there is a great deal riding on the

outcome of a significance test, or a p-value, and you are

not well educated in probability theory or statistics, you

should seek expert help from a local university or other

organizations that use statistics on a regular basis.

Read More:

Crow, Edwin and colleagues (1960). Statistics Manual.

New York: Dover.

Website with many useful statistical links

www.prndata.com/statistics_sites.htm

ASSESS THE IMPACT

0.60

0.50

0.40

0.30

0.20

0.10

0.00 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

C. Probably Random Difference

Before Mean=16 Std Dev=8

After Mean=12 Std Dev=8

Number of Crimes

Proportion of of Crimes
T

he purpose of your work is to help people make

better decisions. To assist decision-makers, you must

tell a clear story that leads from an important

question to possible answers and then to effective

actions. To communicate effectively you need to know

who your audience is and the questions they want

answered. Your story has to address their particular needs.

This story can be told in a written report or in an oral

presentation (see Step 58).

Do not simply recount what you did to detect, analyze,

respond, or assess. This is tedious and does not help

people make actionable decisions from your work. You

must translate your analytical work into a story that

addresses the needs of your audience.

Your work can help answer four basic questions. These

questions correspond to the stages of the SARA process:

1. What is the nature of the problem? (Scanning) 

2 .What causes the problem? (Analysis)

3. What should be done about the problem? (Response)

4. Has the response brought about a reduction in the 

problem? (Assessment)

Clearly, these questions must be made more specific

based on the facts of the problem being examined. Local

residents, for example, might complain about late night

noise and finding litter along their street. Instead of the

general scanning question, you could develop a set of

specific questions, based on the CHEERS test (Step 14):

• What is the nature of the noise incidents? (Events)

• In what ways are these incidents similar? (Similarity)

• Are there recurring instances of late-night noise and

litter that disturb residents? (Recurring)

• Who, when, and where do these incidents occur?

(Community)

• How do these incidents disturb people? (Harm)

• Who expects the police to address the problem?

(Expectation)

Answering the general question - What is the nature of

the problem? - requires you to answer a set of more

specific questions.

Your first task in telling a coherent story is to decide

which kind of question you are seeking to answer. Next,

you should try to structure your account around the basic

theories and approaches described in this manual (e.g.,

the CHEERS test, the crime triangle, or the 80-20 rule).

These are frameworks. A framework is a general "story

shell" linking multiple interacting factors and that can be

applied to a variety of problems. Your choice of

frameworks depends on the problem, your findings, and

the needs of decision-makers. Be sure there is a logical

flow from the basic question, through the framework and

findings, to the answers. Check for gaps in logic. Now

outline your story. There are four basic story outlines that

can guide your work. The details of the story will depend

on the specifics of your problem.

Do not stick religiously to these outlines; we provide them

as a starting point to prompt ideas. Instead, tailor them

to the amount of time you have and, above all, to the

concerns of the people whom you are addressing. Try to

anticipate their questions, and modify the appropriate

outline accordingly. Though we have used technical terms

from this manual in these outlines, you may need to use a

common vocabulary in your presentation. If your audience

is not already familiar with the terminology of problem

analysis, you probably should use it sparingly, or not at all.

Four Story Outlines

1: What is the nature of the problem?

A. Organizing framework - e.g., CHEERS elements.

B. Systematic description of evidence about problem type

and existence:

• What is the nature of the events?

• In what ways are these events similar?

• How often do these events recur?

• When and where do these events occur?

• Who is harmed by these events, and how?

• Who expects the police to address the problem?

C. Implications for analysis and collaborative problem

solving:

• Questions that need answering.

• Definitional and measurement issues.

• Partners who need to become involved.

D. Summary.

5454. Tell a clear story
Crime Analysis for Problem Solvers in 60 Small Steps

2: What causes the problem?

A. Organizing framework for problem - e.g., problem

analysis triangle.

B. Systematic description of problem answering the

following questions:

• Who are the offenders?

• Who or what are the targets?

• At what places and times does the problem occur?

• What brings the offenders and targets together at the

same places? 

• Why don't others step in to prevent these encounters?

• What facilitates or inhibits the problem?

C. Implications for general form of responses that fit 

the information:

• Offender access or control.

• Victim/target behaviors or protection.

• Facility access or management.

D. Summary.

3: What should be done about this problem?

A. Organizing framework for response - e.g., situational

crime prevention:

• Offenders.

• Targets/victims.

• Places.

B. Systematic description of response strategy:

• Increasing risk or effort.

• Decreasing reward, excuses, or provocations.

• Who will carry out actions, when, and where?

• Additional resources required.

C. Implications and anticipated outcomes:

• Direct results.

• Displacement.

• Diffusion.

• Other side effects.

• How evaluation should be conducted.

D. Summary.

4: Has the response reduced the problem?

A. Organizing framework - e.g., principles of evaluation.

B. Systematic description of evaluation:

• Was the response implemented as planned?

• Did the problem change? 

• Why it is likely that the response was a direct cause of

change.

• The magnitude of displacement, diffusion and other 

side effects.

C. Implications for further action:

• Is this problem solving effort complete?

• What further actions are necessary? 

• Should further analysis be conducted?

• Should the response be changed? 

D. Summary.

COMMUNICATE EFFECTIVELY
Maps have an important role in telling compelling

stories about problems. But they need to be clear

to accomplish this. That is, maps must contain as

much relevant information as possible and no irrelevant

information. There are a number of guides to good

cartographic principles available (see box and Read More).

We will illustrate the use of maps to tell stories with a set

of maps from a problem-solving project undertaken by the

Norwegian Police. Figures 1 and 2 illustrate how maps

can be used to describe problems and solutions.

Johannes Knutsson, of the National Norwegian Police

Academy, and Knut-Erik Søvik, of the Vestfold Police

District, were attempting to address a problem of illegal

("gypsy") cabs in a small coastal town of Tønsberg

(population 36,000). On weekends the 30 drinking

establishments draw large crowds and people move back

and forth across a highway, so the highway is closed on

Friday and Saturday nights. A parking area is also closed.

However, legal taxis and busses can move along the

highway. Unlicensed "gypsy" cabs have taken over most

of the business in this area, in part by intimidating the

licensed cab operators. A number of serious crimes had

been attributed to the drivers of these illegal cabs and

they have been the subjects of numerous complaints.

The setting of the problem is shown on two maps in

Figure 1. The left panel is a street map. It shows many

features irrelevant to the problem and fails to show many

features that are important. The right panel is a highly

edited version of this map. It contains only the relevant

features of the base map and adds the important omitted

features, giving a much clearer picture of the setting.

Figure 2 contains two maps summarizing conclusions

from the analysis and important features of the response.

The left map shows the primary travel routes of the gypsy

cab drivers. The gypsy cabs make use of the street

barricades and the parking lots to pick up customers. This

map also shows that the bus stand and (legal) cab stand

are too far from the people using the area. When the

bars close after 3:00 AM there is great demand for

transportation and the illegal cabs are in the best position

to fill the demand. The response map on the right of

Figure 2 shows how the highway barrier was moved to

prevent gypsy cabs from getting to potential customers,

the parking lots blocked off late at night to keep these

cabs out, and how the legal cab stand and bus stand

were moved to locations more convenient for the

customers. This map is an important part of the process

evaluation (Step 46).

Together, these three maps nicely illustrate the nature of

the problem and what was done about it. The result of

this project was the virtual elimination of the gypsy cab

problem in Tønsberg, without increasing disorder.

Knutsson and Søvik heavily annotated these maps to

show features that a typical geographic information

system would not show. This is good practice. Much

information about problems is not contained 

in computers.

Still, there are a number of features of good maps that

are missing. There is no compass direction. However,

direction plays no part in the problem so its absence does

not detract from clarity of the maps. Also missing is a

scale showing the relative size of map features. This

impedes understanding of those who are unfamiliar with

the area.

Read More:

Boba, Rachel (2005) Crime Analysis and Crime Mapping:

An Introduction. Thousand Oaks, CA: Sage Publications.

Harries, Keith (1999). Mapping Crime: Principle and

Practice. Washington, DC: National Institute of Justice,

Crime Mapping Research Center.

Knutsson, Johannes and Knut-Erik Søvik (2004) Gypsy

Cabs in Tønsberg. Submission to the Herman Goldstein

Awards. (accessible at www.popcenter.org)

Jerry Ratcliffe has a list of mapping tips at:

www.jratcliffe.net

5555. Make clear maps
Crime Analysis for Problem Solvers in 60 Small Steps

COMMUNICATE EFFECTIVELY

1. Know what information your audience will find useful (and what information is confusing).

2. Keep maps simple. Eliminate all features that do not contribute to understanding the problem.

3. Avoid graphics that draw more attention to themselves than the data.

4. Include details that help the viewer understand the problem, even if that means adding this information by hand.

5. Include a scale and, if needed, a compass orientation (usually North is to the top).

6. Use meaningful gradations to show intensity of hot spots. For example show colors becoming increasingly hot

(yellow to red) as the problem worsens.

7. Apply the correct dimension of crime concentration: dots for places (and sometimes victims); lines for

concentrations along streets and highways; and areas for neighborhoods.

8. Make use of tables and figures along with maps.

Figure 1:

Locating The Problem And

Showing Its Setting

Base map of problem settting Edited map of problem setting

Figure 2:

Analyzing The Problem and

Showing Response

Description of problem based on

analysis Description of response

HIGHWAY

closed section

Tønsberg downtown

area - 30 bars,

taverns etc

Barriers

P =parking lot

P =no admission

Section of highway

temporarily closed

off during weekend

nights

GYPSY CABS

Bus Stand Moved Bus

Stand

P =parking lot

P =no admission

Kiosk

Cab Stand

HIGHWAY

closed section

HIGHWAY

closed section

P =parking lot

P =no admission

New Cab

Stand

Cab Stand

Moved Barriers

Creating Useful Maps
T

ables are effective tools for telling a compelling story

if they are made simple. But the software used to

create tables adds unnecessary and distracting

packaging - the lines and labels used to interpret the data

- and analysts do not always organize tables in a way that

makes intuitive sense.

Assume that you are trying to show that the way beer is

displayed facilitates beer thefts from stores. Some stores

display the beer near the front entrance and some at the

rear. You are trying to show that rear display stores have

fewer incidents of beer thefts than those where the

display is in the front. Table 1 gets in the way of this

message. The data are poorly organized and the

packaging is distracting.

Table 2 properly organizes the data. The percentages are

made central to the story. Because the raw numbers do

not tell the main story, but may be useful to a reader who

wants to look more closely, they are made subservient by

enclosing them in brackets. Finally, instead of row

percentages (as in the first table), Table 2 uses 

column percentages.

Whenever we examine a relationship in which something

may be causing something else, it is best to put the cause

in the columns and use column percentages. Then, make

comparisons across the rows. Here, we see immediately

that 29 percent of the front-display stores had no thefts

compared to almost 83 percent of the rear-display stores.

At the opposite extreme, almost 46 percent of the frontdisplay stores had three or more thefts, but none of the

rear-display stores did.

Table 2 has less packaging. The bold borders have been

removed and replaced by thin lines. Inside, the only

remaining line separates the title from the content.

Instead of lines, space is used to guide the reader's eye

across rows and down columns. By informing the reader

in the title that the important numbers are percentages

(and the raw numbers are in brackets), there was no need

to include a percent symbol in each cell. Only the column

total remains. This tells the reader that the important sum

is vertical. Finally, all percentages are rounded to one

decimal place, thus allowing the column figures to line up,

making interpretation easier. With all of these changes,

most of the content of the table is data rather 

than packaging.

A problem often has multiple causes. Though tables can

be constructed to show large numbers of causes, a single

table communicates poorly when you examine more than

two causes. The basic principles of table construction

remain the same:

• All the causes go in the same direction 

(usually columns).

• Summation goes in the direction of the cause 

(down columns).

• Comparison of causes goes in the opposite direction

(across rows, if causes are in columns).

Table 3 is called a three-dimensional table because three

things are examined (the earlier tables were two

dimensional). Table 3 answers the question: is the

relationship between display location and theft different

for two different store chains (Drink-Lots and Tippers). The

answer is that it is not. There is the same basic pattern for

both chains that we saw in Table 2. In both cases, we sum

the column and compare front-display stores to reardisplay stores. This implies that any store that displays

beer at the rear will experience less theft, regardless of

which chain it belongs to.

In effect, Table 3 holds constant the type of store. Other

factors can be held constant if we think they are

important. For example, we could group stores by size

(small, medium and large), and separately analyze the

relationship between display location and theft for each

size category. This would require three panels, but

otherwise the same principles apply.

Take note of several other features of Table 3:

• If you add the raw numbers (in brackets) in the DrinkLots cells to their corresponding cells under Tippers, you

get the raw numbers in Table 2. In other words, Table 2

is a summary of Table 3. But you cannot derive Table 3

from Table 2.

• Because Table 3 contains two possible causes of the

problem, we have added a vertical line to draw

attention to the two types of stores.

• The row labels apply to both store types, so there was

no need to duplicate them.

• Because of rounding in the percentages, they sometimes

add to over 100. In some instances these sums can be

just under 100, usually 99.9. Such small deviations are

seldom of much concern.

If you routinely produce the same tables for the same

decision-makers, show them several different table

formats with the same data. Determine which format

helps them the most, and then use this standard format.

5656. Use simple tables
Crime Analysis for Problem Solvers in 60 Small Steps

COMMUNICATE EFFECTIVELY

Number of theft reports

0

1-2

3 or more

Total

Front

7 (17.5%)

6 (46.15%)

11 (100%)

24 (37.5%)

Rear

33 (82.5%)

7 (53.85%)

0 (0%)

40 (62.5%)

Total

40

13

11

64

Location of display

Table 1: Location and Beer Theft (June)

Thefts in June

0

1-2

3 or more

Total

Front Rear

Location of display

Table 2: Percent of Stores with Reported Beer Thefts

(Numbers in Brackets)

Thefts in June

0

1-2

3 or more

Total

Front Display Rear Display Front Display Rear Display

Drink-Lots Stores Tippers Stores

Table 3: Percent of Stores with Reported Beer Thefts by Retail Chain 

(Numbers in Brackets)

29.2

25.0

45.8

100.0 

(7)

(6)

(11)

(24) 

82.5

29.2

0.0

100.1

(33)

(7)

(0)

(40) 

30.8

23.1

46.2

100.1

(4)

(3)

(6)

(13)

84.2

15.8

0.0

100.0

(16)

(3)

(0)

(19)

27.3

27.3

45.5

100.1

(3)

(3)

(5)

(11)

81.0

19.0

0.0

100.0

(17)

(4)

(0)

(21)
L

ike tables and maps, figures and charts are effective

tools for conveying information, but only if they are

kept simple. All figures consist of two parts -

packaging and content. Content is the information you

are interested in conveying to others. The purpose of the

packaging is to ensure that the content can be quickly,

easily, and accurately interpreted. Simplicity means

keeping the packaging to a minimum. The most common

mistake is adding elements that get in the way of the

story. To illustrate this, we begin with an example of a

poorly designed figure. Then we will show how figures

become clearer and more powerful by making 

them simpler.

Figure 1 is a pie chart that is supposed to show how

burglars entered homes. The 3-D image distorts the

message. As we will see later, doors are the biggest

problem, and the rear window ranks fourth, behind

"other," as the entry of choice for these burglars. The 3-D

effect inflates the importance of the slices in the front (in

this example, front windows, the least likely point of entry)

while deflating the importance of the slices in the back.

The single valuable feature of a pie chart is that it shows

how the parts contribute to the whole. This is lost when a

3-D effect is used. Note that a variety of shades and

patterns need to be used to display the six categories. This

adds clutter.

Figure 2 shows the distortion that 3-D effects can produce

in bar charts. Comparing bar heights is difficult because

one has to choose between the front top edge and the

back top edge of the bar. 3-D effects should never 

be used.

This chart has a number of other features that make it

hard to use: surface shading that masks contrasts

between the bars and background, redundant bar labels

and vertical axis labels, and distracting horizontal lines.

The frame around the figure is superfluous.

The simple bar chart in Figure 3 communicates

information very effectively because all the confusing

features of Figure 2 have been removed. If we wanted

each bar to show the exact percentage, we could label

the tops of the bars. But then we should remove the

vertical axis, as this feature communicates the 

same information.

Additionally, the data in Figure 3 have been reorganized.

Instead of raw numbers of burglaries, the chart shows the

percentage of the total. This communicates two points:

which methods are more frequent, and what part of the

whole each method represents. If you need to show the

relative contribution to a whole, use percentages in a bar

chart rather than a pie chart.

Another feature of Figure 3 is that the categories are

arranged in a meaningful order: from most to least. This

points to where your readers should focus their attention.

Meaningful order is hard to communicate in a pie chart

because it has no obvious beginning or end. There really is

no need to use a pie chart because bar charts can

communicate better. When you have data in categories,

bar charts are simple and effective.

5757. Use simple figures

Figure 1: Methods of Entry Figure 2: Methods of Entry

front door rear door

rear window front window

unknown

other

front

window

rear

window

front

door

rear

door

other unknown

60

50

40

30

20

10

0

6

16

54

31

20

7
Crime Analysis for Problem Solvers in 60 Small Steps

Do not forget the figure title. In Figure 3 the title boldly

tells a story. Not only is this far more interesting than

"Methods of Entry," it makes the story unambiguous. In

short, Figure 3 can stand by itself. Without reading any

accompanying text, the reader gets the point.

The final figure depicts a line graph. These are typically

used when tracking data over time. In Figure 4, the data

cover 6 months. The dots symbolize the burglary count,

and the lines indicate a continuous connection over time.

You should label the vertical axis so the figure

communicates the story on its own. In this figure, we

know at a glance that the vertical axis shows the number

of burglaries, rather than the burglary rate.

If you prefer to show the number of events at each time

period, label the dots, but remove the vertical axis: it's

now redundant. Be careful, however. Numerical labels at

every time point can make a chart difficult to read. If

multiple graphs are shown in the same figure (for

example, the trend in burglaries for several police

districts), make sure the different lines are clearly marked

and easily differentiated over the chart.

Read More:

Kosslyn, Stephen (1994). Elements of Graph Design. New

York: W. H. Freeman.

COMMUNICATE EFFECTIVELY

front

door

rear

door

other window unknown front

window

%

45.0

40.0

35.0

30.0

25.0

20.0

15.0

10.0

5.0

0.0

60

50

40

30

20

10

0

Figure 3: Doors are the Problem

April May June July August Sept

Figure 4: Burglary is Declining

Designing Effective Figures

• Keep them simple. Don't over-package.

• Do not use superficial effects, like 3-D.

• Avoid pie charts.

• Use bar charts for data that comes in categories.

• Use line graphs for trends over time.

• Use labels effectively.

• Choose titles carefully.

• Make them stand on their own, without help from the

text.

Number of Burglaries
A

presentation should begin with a basic question,

use a framework to move through a description of

findings, and end with a set of specific conclusions

(see Step 54). Graphical material should be prepared

following the guidance in Steps 55 through 57. In this

step we will focus on the story you are telling. In Step

59, we will look at how the presentation should be

delivered, including the use of PowerPoint.

The main focus of your presentation should be to answer

specific questions that will aid decision-making, and it

should consist of the following:

• A set of slides organized around your story.

• A graphical motif or outline slide to keep your audience

focused on the story.

The slides illustrates a presentation of analysis findings.

The presenter, Sergeant Smith, has two goals. The first is

to answer the question, "What causes this problem?" The

second is to open up a discussion of possible responses.

The title slide asks the question (and introduces the

presenter). This and slides 2 to 4 constitute the

introduction. Slide 2 reinforces a set of already agreed

points that serve as a foundation for what follows. Slide 3

outlines the presentation and slide 4 summarizes 

data collection.

The framework is presented in the fifth slide. Sgt. Smith

uses the crime triangle. He keys all of the findings that

follow to this triangle. (Note that this only works if

Smith's audience is already familiar with the triangle. If

they are not, then Smith should use a different

framework.) To reinforce this message, and to keep the

audience from getting lost, Sgt. Smith uses the triangle

motif throughout the presentation of findings, with slight

but important modifications: the shaded side and the

color change as slides move from targets and guardians,

to places and managers, and to offenders and handlers.

The circular arrow in slide 5 indicates the

counterclockwise order in which Sgt. Smith will present

the findings. So in this slide, Sgt. Smith has simultaneously

described his framework and provided an outline of the

main findings.

Slides 6 to 13 present tables, figures and maps that tell

the audience about the elements described in the

framework. A bar chart might show the actions used to

protect targets. A location map might show the places

where the problem is particularly prevalent in contrast to

where it is absent. Photos might show particularly

important features of these sites. A table might show the

frequency with which offenders are arrested.

Slide 14 summarizes these findings. Here, the triangle

shows all sides shaded, reinforcing the point that the

separate findings are part of a larger whole. The final

slides list response options that are consistent with the

findings and options that are inconsistent. Though Sgt.

Smith gives his expert opinion, these final slides are

meant to open up a discussion that is informed by the

earlier findings. It is the decision-makers who have the

final say in this matter.

It is important to keep your audience focused on the

larger story and from getting lost in the details. Two

methods for accomplishing this are to use an ongoing

motif (like the triangle in the figure) or a highlighted

outline slide. When using an outline slide, the outline is

shown before each topic. The topic to be presented is

highlighted on the outline and the other topics are

dimmed. In Sgt. Smith's presentation, the outline slide

would be shown four times, before each of the 

main topics.

Handouts of your slides are useful, but there are some

limitations. You can make last-minute changes in the

slides more easily than in the handouts. If you expect

major last-minute changes, handouts may not correspond

to the images. Color slides are often not legible when

photocopied in black and white. If you are using

PowerPoint, then the "pure black and white" option in

the "Print" menu will temporarily convert your color slides

to black and white for printing.

Most decision-makers are not as interested as you are in

the methods you used to analyze your problem. Therefore,

do not spend a great deal of time describing your

methods, unless this is the objective of the presentation.

Rather, summarize the main elements (see slide 4). You

can prepare separate slides about methods, held in

reserve, should audience members have questions about

your methods.

Read More:

RAND, Guidelines for Preparing Briefings, Santa Monica,

CA, 1996,

www.rand.org/publications/CP/CP269/CP269.pdf

Ratcliffe, Jerry H, (2004) "Jerry's Top Ten Crime Mapping

Tips."

http://www.jratcliffe.net/papers/Jerry%27s%20top%20ten

%20mapping%20tips.pdf

5858. Organize powerful presentations
• Undertaken by Problem Analysis Section

• Data from a Variety of Sources

-Reported X events

-Interviews with Merchants & Shoppers

-Offender Interviews

-Review of CCTV recordings

• Experts from other Police Forces

Analysis of XYZ Problem

Causes of the XYZ Problem

• Data sources used

• How the data was organized

• Why we have this problem

• Possible responses

This Presentation Shows

Sgt. Rodney Smith

Problem Analysis Section

What Causes the XYZ Problem ?

• High number of reported X events.

• Concentrated in sector Y.

• First documented in 1986.

• Does not respond well to enforcement.

• Common to other police forces.

What is the XYZ Problem ?

Targets and Handlers

a.

b.

Places and Managers

a.

b.

Offenders and Handlers

a.

b.

Targets and Handlers

a.

b.

Places and Managers

a.

b.

Offenders and Handlers

a.

b.

Crime Analysis for Problem Solvers in 60 Small Steps

COMMUNICATE EFFECTIVELY

1 2

3 4

5 Elements of the XYZ Problem

Slides describing targets and guardians

Slides describing places and managers

Slides describing offenders and handlers

6-13

14

A bulleted summary of the previous slides

15 Inconsistent Responses

16 Consistent Responses

Handlers

Offenders

Managers

Places

Targets

Gaurdians
A

ll professionals are required to make presentations,

and presentation skills are becoming as important

as good writing. The key to a good presentation is

thorough preparation. The following points come from a

variety of sources, including our own experiences - 

good and bad.

Preparation

Never try to "wing it." Even experienced presenters are

often nervous, so do not be concerned about prepresentation jitters. Thorough preparation helps keep

nerves under control.

1. Know your topic.

2. Know your audience, including who else is

presenting.

3. Establish presentation length.

4. Prepare to finish a few minutes early, but take full 

time if you need it.

5. Rehearse presentation and time it.

6. Rehearse again, if necessary.

Check out the room on the presentation day

Making sure you understand your presentation

environment accomplishes three objectives. First, it keeps

you from being surprised. Second, it allows you to make

contingency plans. Third, it helps you remain calm. This is

particularly true when you are presenting at a conference

or some other venue outside your agency. Hotel

conference facilities vary considerably in their layout.

1. Is the equipment you need in place? 

• Flip charts

• Black/white boards 

• Chalk/marker 

• Projectors 

• Microphone 

• Laser pointer 

2. Do you know how to use the equipment?

3. Have you tried it out?

4. Do you know how to summon the technician?

5. Do you know how to dim lights?

6. Are there parts of the room where the audience will

have trouble seeing or hearing you?

Projector

Modern presentation equipment is both complex and

failure-prone. Be sure you know how it works and have

backup plans. If time permits, we always conduct a trial

run with the equipment in the room. And during this trial

run, we have found it useful to sit in different parts of the

room and view the most complex slides. Even if you

cannot make adjustments, you can forewarn your

audience later. (For example, "Those of you on the left

might want to move to the center as there are some

graphics that are hard to see from the left-most seats.")

1. Locate the projector in the best position for the

audience and yourself.

2. Make sure it does not block the view of the screen.

3. If necessary, get help with presenting slides.

4. Make sure slides can be read from the back of 

the room.

5. Draw curtains or blinds if necessary.

6. Never assume things will work as planned!

Presentation style

Though knowing your material is critical, you need to

have a style the audience appreciates. At minimum, make

sure your audience does not have to work to overcome

your style to understand your presentation. Treating your

audience with respect is absolutely critical.

1. Do not read your paper even if you have supplied a

written version.

2. Speak from notes (using cards prevents you from

losing your place).

3. Begin politely (thank chair, introduce yourself, greet

audience, etc.).

4. If possible, stand up and speak (this helps keep

control of the audience).

5. For lengthy presentations, you can vary where you

stand (but don't walk about restlessly).

6. Do not block the audience's view of the slide images.

7. Make sure you can be heard.

8. Don't speak too fast (about 120 words per minute 

is good).

9. Maintain eye contact with the audience (but not just

one person!).

10. Make sure your audience knows when it is

appropriate to ask questions - during the presentation

or after.

5959. Become an effective presenter
Crime Analysis for Problem Solvers in 60 Small Steps

11. Repeat questions so others can hear, answer 

concisely, and ask the questioner whether you have

addressed their question.

12. Make sure handouts are clear (and that you have

enough).

13. End on time.

14. Try to enjoy yourself!

Presentation Software

PowerPoint and other similar presentation software allow

the audience to receive the information simultaneously in

two modes: visually and aurally. They are therefore more

likely to understand and remember key points. There are

four dangers from electronic presentations. First, they can

result in standardized presentations that quickly become

boring for more sophisticated audiences. Second, they

can become so complex that the audience pays more

attention to the media than the message. Three,

breakdowns become more common with greater

complexity. Four, they can stifle questions from the

audience. Watching you fix a multimedia extravaganza

bores your audience and wastes there time. Remember

the KIS principle: Keep It Simple.

1. Don't read your slides - your talk should not just be a

repetition of the slides.

2. Look at the audience - not at your slides!

3. Begin with the title of the presentation, your name

and affiliation (but not your qualifications).

4. Use only one form of slide transition throughout, and

only use a simple transition that does not distract the

audience from your main points.

Individual PowerPoint Slides

Keep each slide simple, too. Lots of text on a slide is hard

to read. Your objective is to make each slide telegraphic.

Each slide should focus attention on a critical point and

avoid distractions from that point. So make them easy to

read and understand.

1. Make only one point.

2. Present just enough detail to address the point and

no more.

3. Avoid distracting sound effects, animation, type fonts,

and transitions.

4. Use dark background (e.g., deep blue) and light colors

for text (e.g., yellow).

5. Use large fonts and contrasting colors (not clashing,

e.g., blue and deep orange is clashing, but blue and

yellow is contrasting).

6. Avoid thin lines and letters that cannot be easily

distinguished from the background. This can be a

particular problem with line charts and maps.

7. Avoid too much red - you should use red selectively to

emphasize important points.

8. Use visual graphics rather than words when possible.

9. Use clear and simple pictures, maps, figures,

and tables.

10. Use short bulleted phrases, not narratives, on 

word charts.

11. Ensure that each bullet is related to the main point

of the slide.

Finally, be safe

Assume things will go wrong! If the projector fails, be

ready with overhead projection slides and a projector. If

that fails too, use your handouts as a substitute. If you

are prepared for a breakdown, you will be less nervous

and your audience will be sympathetic.

1. Avoid technologies that break down frequently or

ones that you are not familiar with.

2. Have a backup plan for equipment and 

software failures.

3. Provide handouts of slides as supplements.

Read More:

Ratcliffe, Jerry H, (2004) "Jerry's Top Ten PowerPoint Tips."

http://www.jratcliffe.net/papers/Jerry%27s%20top%20ten

%20powerpoint%20tips.pdf

Ratcliffe, Jerry H, (2004) "Jerry's Top Ten 

Presentation Tips."

http://www.jratcliffe.net/papers/Jerry%27s%20top%20ten

%20presentation%20tips.pdf

COMMUNICATE EFFECTIVELY
Much of what we know about problems today was

unknown 20 years ago. This accumulation of

knowledge is largely due to the sharing of

knowledge by police practitioners and researchers in the

United States, Canada, United Kingdom, and other

countries. Steps 54 to 57 described how to communicate

to decision-makers in your police force and in your

community. You also have a duty to improve your

profession by sharing your work outside your local agency

and community.

There are two approaches to communicating with your

peers. The first is through written materials. These may be

published in reports, professional periodicals, or popular

press articles. The second is through presentations at

professional conferences and meetings. The most effective

strategy for communicating information is to use a

combination of these approaches.

Written reports can present a wealth of detailed, useful

information that others can use as reference material.

There are a number of ways of disseminating written

information. It can be made available in a downloadable

format from websites. It can be published in professional

periodicals. Shorter pieces designed to capture people's

attention can be published in professional newsletters and

other periodicals. Finally, encouraging professional

journalists to write about your efforts can reach even a

wider audience. Shorter and more easily accessible pieces

reach a wide audience, but contain less information.

Conferences allow face-to-face communications, questions

and answers, and discussions of the latest developments.

Informal discussions are useful for exchanging viewpoints

on ideas that have not developed enough to be

published. And they allow you to seek advice from peer

experts on difficult problems.

The United States and the United Kingdom hold annual

conferences on problem-oriented policing. There are also a

host of crime analysis and other police conferences

around the globe where you can present new information

on problem solving.

Finally, you should also consider conferences of other

professions, particularly if you have been working with

partners from other fields. The principal drawbacks to

conferences are the limited time available to present

material, the lack of detailed permanent records of

conference proceedings, and the relatively small numbers

of people who attend. But attendees can spread

information to those not present.

A comprehensive communications strategy should include

the following:

1. For people interested in the details, a technical report

downloadable through an easily used website.

2. For a large audience of general interest, one or more

short articles in professional or popular periodicals,

with references to the website.

3. For professional colleagues and academics, a longer

article in a professional journal.

4. For a small but influential group of professional

colleagues, at least one presentation at a 

professional conference.

Additionally, it is helpful to send copies of articles to

people who are interested in the topic you are

investigating. This not only communicates your ideas, but

also allows you to solicit advice as to how to

communicate your ideas to others.

Professionals are particularly interested in the following:

1. Discoveries of new or changing problems.

2. Advances in analytical techniques that can answer

new questions, or answer old questions more

precisely and with less error.

3. New responses to problems or new applications of 

old responses.

4. Evidence about the effectiveness, lack of effectiveness,

or side-effects of responses.

Each of these topics can be written as a case study of

your particular problem. The basic outline for a useful case

study covers four points:

1. Dissatisfaction with the old situation - why the

standard understanding or practice is insufficient in

particular circumstances.

2. Search for alternatives - how a new understanding or

practice was discovered.

3. Evidence supporting alternatives - comparison of old

and new approaches.

4. Conclusions and implications - summary of what

people should consider, given this new information.

6060. Contribute to the store of knowledge
Crime Analysis for Problem Solvers in 60 Small Steps

This outline follows the SARA process. Scanning reveals

dissatisfaction with a particular circumstance. Analysis is a

search for a new understanding of the problem. Response

requires a systematic comparison of alternative

approaches and the selection of a particular new

approach. And assessment summarizes what one has

learned from the experience.

The table shows how this outline can be applied to each

of the four case study topics. These types of case studies

can be combined, as circumstances require. A new

technique for problem analysis might reveal a new type of

problem, for example. In such a circumstance, the first two

types of case study can be combined.

Similarly, a description of a new response to a problem

might include evaluation information, thus combining the

last two types of case study. Other combinations 

are possible.

Finally, we offer a plea on behalf of crime analysis as a

profession and crime science as a discipline. However

much you want to make yourself clearly understood, never

give in to the temptation to exaggerate your evidence.

Nothing is more likely to damage your reputation, and

that of your colleagues, than being seen to stretch the

facts. Other people may cut corners or leap to

conclusions. Crime analysts lend diligence and integrity to

what is sometimes a haphazard process. If you don't

know the answer or only partly understand the problem,

say so. That way, when you do know the answer, people

will be more willing to trust your professional judgment.

The 21st century is becoming the century of analysis in

policing, and you can make a large contribution. A

hundred years from now, analysis will be firmly

established in policing, and much will have changed. The

technology will certainly be different. But more

importantly, our successors will know a great deal more

about crime and its prevention than we do. And they will

know this because you and people like you asked

important questions, collected and analyzed data, and

reported your results with honesty and clarity.

COMMUNICATE EFFECTIVELY

Outline

I. Dissatisfaction

II. Search

III. Evidence

IV. Conclusions

1. New Problem

Discovery of an

anomalous situation

Exploration of what

is different

Comparison of old

problem to new

problem

What this implies for

problem solving

2. New Analytical

Technique

Why old technique is

limited

How the new

technique was

discovered

Systematic

comparison of old

technique to new

based on objective

criteria

Circumstances where

new technique is

particularly helpful

3. New Response

Why old response is

limited

How the new

response was

discovered

Systematic

comparison of old

response to new

based on objective

criteria

Circumstances where

new response is

particularly helpful

4. New Evidence

on Effectiveness

Uncertainty of

effectiveness of

response under

particular

circumstances

Difficulties in

evaluating response

in these

circumstances

Evaluation methods

used and their results

Circumstances where

response should be

used and expected

results

Four Types of Case Studies
GLOSSARY AND INDEX

Crime Analysis for Problem Solvers in60 small steps

Term Definition Step

3-D Mapping

80-20 rule

Acute hot spots

Acute temporal clustering

Acute troubles 

Adaptation

Analysis

Anticipatory benefits

Anticipatory benefits, pseudo

Aoristic analysis

High-definition mapping that

portrays locations within buildings

The principle that a few people or

places are involved in a large

proportion of events

Hot spots that suddenly appear,

i.e., have not been present for a

long time, not chronic (See

Chronic hotspots and 

Chronic problems)

A very high concentration of crime

in a small part of 24-hour cycles

Transient sets of recurring events

that might go away without

engaging in problem solving

activities, but could also evolve

into chronic problems

Long-term changes in offender

population behaviors in response

to crime prevention

The second stage in the SARA

process, involving systematic

examination of the problem to

identify possible causes that might

be susceptible to responses

Benefits from crime prevention

that begin prior to initiation of

crime prevention treatment

The appearance of anticipatory

benefits caused by smoothing data

(i.e., the use of a moving average)

A statistical method for

determining the 24-hour rhythm of

crimes when the exact time of

crime commission is unknown

24

18, 20, 22, 30, 31, 54

23

25

14

11, 46

4, 5, 6, 7, 8, 14, 15, 16, 18, 20,

23, 32, 33, 35, 36, 38, 44, 46, 52,

54, 55, 58, 60

11, 46, 52

52

25
GLOSSARY AND INDEX

Term Definition Step

Assessment

Attractors, Crime

Behaviors

Boost accounts

Broad-spectrum treatments

Broken windows policing

Buffer zone

Case-control study 

The fourth stage in the SARA

process, involving evaluating the

effectiveness of the response

Areas of criminal opportunities

well known to offenders

One of two criteria for classifying

problems describing aspects of

harm, intent, and offender-target

relationships (see Environments)

An explanation for repeat

victimization that suggests that the

rewards to the offender for the

first crime encourage the offender

to repeat the offense against the

same victim or to tell other

offenders who then attack the

same victim (see Flag accounts)

Crime prevention measures that

are effective against a wide variety

of methods for committing a type

of crime

A proposed policing strategy based

on the principles that small

offenses add up to destroy

community life and that small

offenses encourage larger ones,

consequently police should pay

particular attention to disorders 

Area around a place or area.

Often an area around a facility, hot

spot, or treatment area

A systematic comparison of

troublesome persons, places, times,

or events to untroublesome ones

to find out the characteristics that

might cause the problem. This

type of study is particularly useful

when troublesome cases are a very

small proportion of all cases

1, 4, 7, 24, 37, 38, 46, 54, 55, 60

17, 28

15

29

49

5

16, 51

17, 32, 33
GLOSSARY AND INDEX

Crime Analysis for Problem Solvers in60 small steps

Term Definition Step

Cases

CHEERS

Chronic hot spots

Chronic problems

Community policing

CompStat

Content

The people, places, and events you

are studying - offenders, targets,

victims, facilities, time periods (e.g.,

months or weeks), crimes, and so

forth. In case-control studies,

cases are the problem people,

places, or events (see Case-control

and Controls)

Acronym for elements of defining a

problem: Community, Harm,

Expectation, Events, Recurring,

and Similarity

Hot spots that persist for a long

time (see Acute hotspots)

Long-term sets of recurring events

that show no sign of abating and

are largely resistant to traditional

police work

Community policing focuses on

crime and social disorder through

the delivery of police services that

includes aspects of traditional law

enforcement, as well as

prevention, problem-solving,

community engagement,

and partnerships

A police management system,

pioneered in New York City, that

uses up-to-date crime pattern

information (often processed with

a geographic information system)

to hold geographic commanders

(e.g., precinct and district)

accountable for reducing crime

The substantive information in a

table or figure

22, 32, 33, 37, 53

14, 15, 54

23

14

1, 3, 4, 5 

3, 4, 5

56, 57
GLOSSARY AND INDEX

Term Definition Step

Control group

Controls (for analysis)

Controls (in case-control

studies)

Controls (on offenders)

Correlation

Costs

CPTED

A group of people or an area that

is similar to the treatment group or

area, but does not receive

treatment. Used in evaluations to

control for the impact of other,

non-treatment influences on crime

Statistical and evaluation design

procedures to isolate the effect of

one factor on some outcome from

that of others. A group of people

or areas not getting a response

that are compared to those

receiving the response to show

what would have happened to the

response group if the response

group had not received the

intervention (see Control group)

In a case-control study, controls

are those people, places, times, or

events that do not have the

outcome being studied, in contrast

to cases which do have the

outcome. For example, in a casecontrol study of high-assault bars,

the cases are bars with many

assaults and the controls are bars

with few or no assaults (see Cases,

and Case-control study)

People and situations that reduce

potential offenders' willingness or

capabilities to commit crimes

A measure of association between

two characteristics

Expenses or hardships associated

with criminal events or 

prevention measures

See Crime Prevention Through

Environmental Design

47, 49, 51 

47, 48, 49, 51

32, 33

9, 15, 17, 39, 42, 43, 48

33

6, 12, 38, 40, 44,
GLOSSARY AND INDEX

Crime Analysis for Problem Solvers in60 small steps

Term Definition Step

CRAVED

Crime Mapping/Maps

Crime Prevention Through

Environmental Design

Crime triangle

Crime-neutral areas

Cycles

Defiance

Den (of iniquity) problems

Diffused temporal clustering

An acronym describing the

characteristics of items most likely

to be stolen and standing for

Concealable, Removable, Available,

Valuable, Enjoyable,

and Disposable

Examining how crime is spread

geographically by showing where

it is occurring on maps. See

Geographic Information Systems

A set of principles for designing

and laying-out secure buildings

and public spaces

See Problem analysis triangle 

Areas attracting neither offenders

nor targets, with adequate controls

on behaviors 

Regular fluctuations in crime that

correspond to daily, weekly,

monthly, annual, or longer changes

in human activity

Offenders challenge the legitimacy

of prevention efforts and commit

more offenses rather than fewer

Problem characterized by

substantial involvement of repeat

places (see Problem analysis

triangle, place). Occurs when new

potential offenders and new

potential targets encounter each

other in a place where

management is weak

A relatively even, or random,

spread of crime throughout 

24-hour cycles

28, 31

1, 4, 5, 16, 17, 21, 23, 24, 29, 55,

58

24

8, 35, 54, 58

17

22, 25, 26, 47, 50

11

8, 15

25
GLOSSARY AND INDEX

Term Definition Step

Diffusion contamination

Diffusion of benefits

Diffusion of benefits, crime

type

Diffusion of benefits,

geographical

Diffusion of benefits, tactical

Diffusion of benefits, target

Diffusion of benefits, temporal

Diffusion-Displacement sites

Displacement

Displacement contamination

Displacement countermeasures

Displacement, crime type

Displacement, geographical

Displacement, tactical

Occurs when diffusion of benefits

influences the control group or

area during an evaluation. Leads

to undervaluing the treatment (see

Displacement contamination)

Reducing crime beyond the focus

of the prevention scheme; a

multiplier of effectiveness

Additional crime types blocked

Additional prevention over space

Additional methods thwarted

Additional targets protected

Additional prevention over time

Areas used to detect diffusion of

benefits and displacement that are

separate from control group and

treatment group

Offenders changing their behaviour

to thwart preventive actions

Occurs when crime is displaced

into the control group or area

during an evaluation. Leads to

inflation of effectiveness (see

Diffusion contamination)

Prevention implemented to prevent

expected displacement

Offenders change type of crime

Offenders move spatially

Offenders switch method for

committing crime

51

11, 13, 38, 47, 49, 51

13

13

13

13

13

51

1, 4, 11, 12, 13, 38, 40, 46, 48,

49, 50, 51, 54

48, 49

48

12, 13, 49

12, 13, 46, 48

12, 13, 49
GLOSSARY AND INDEX

Crime Analysis for Problem Solvers in60 small steps

Term Definition Step

Displacement, target

Displacement, temporal

Distribution

Duck (sitting) problems

Edges

Enablers, crime

Environments

Facilitators

Facilitators, chemical

Facilitators, physical

Offenders switch type of target 

or victim

Offenders switch time or day

A distribution shows how many

cases, or what proportions of the

cases, have each of the values for

a variable

Problems characterized by

substantial involvement of repeat

victims (see Crime triangle). Occurs

when victims continually interact

with potential offenders at

different places, but the victims do

not increase their precautionary

measures and their guardians are

either absent or ineffective

Boundaries between areas where

people live, work, shop, or seek

entertainment

Places with little regulation 

of behavior

A criterion for classifying problems

describing where the problem

takes place (see Behaviors)

Physical items, social situations, or

chemical substances that help

offenders commit crimes or acts 

of disorder

Substances that increase offenders'

abilities to ignore risk, reward,

or excuses

Things that augment offenders'

capabilities, help overcome

prevention measures, or 

incite deviancy

12, 13, 49

12, 13, 48, 49

22

8, 15

16

17

15, 28, 30

34

34

34
GLOSSARY AND INDEX

Term Definition Step

Facilitators, social

Facilities

Facilities, risky

False Negative 

False Positive

Flag accounts

Focused temporal clustering

Framework, story

Generators, crime

Geographic Information

System

Situations that provide support

that stimulates crime or disorder

by enhancing rewards from crime,

legitimating excuses to offend, or

by encouraging offending

Places that have special functions,

like schools, businesses,

and restaurants

Facilities that are frequent sites for

crime and disorder

An error in which the decision

maker predicts something will not

occur, but it does occur. Also

known as a Type 1 error

An error in which the decision

maker predicts something will

occur, but it does not occur. Also

known as a Type 2 error

An explanation for repeat

victimization that suggests that

some people are particularly

vulnerable because of their

occupation or their ownership of

hot products (see Boost accounts)

Clustering of crime in distinct time

ranges during 24-hour periods

A general "story shell" linking

multiple interacting factors and

that can be applied to a variety 

of problems

Areas to which large numbers of

people are attracted for reasons

unrelated to criminal motivation

See GIS

34

15, 18, 20, 23, 25, 27, 28, 30, 34,

38, 39, 42, 43, 44, 48

18, 20, 23, 27, 28, 29, 34, 44

37, 53

37, 53

29

25

54, 58

17
GLOSSARY AND INDEX

Crime Analysis for Problem Solvers in60 small steps

Term Definition Step

GIS

Graded response

Handler

Home Office

Hot areas

Hot dots

Hot lines

Hot products

Hot spots

Abbreviation for Geographic

Information Systems. These are

computer databases where all

information is linked to geographic

locations so that the data can be

mapped. This allows comparisons

of different areas and places for

the same information, and

examination of how two or more

types of information vary together

geographically. GIS is at the heart

of all modern crime 

mapping processes

The response increases in intensity

or form as the number of repeat

victimizations increases. An

intervention used to reduce 

repeat victimization

Someone who knows the offender

well and who is in a position to

exert some control over his or 

her actions

The British equivalent of the U.S.

Department of Justice, which has

funded much research on 

crime prevention

Types of hot spots showing

neighborhoods where crime 

is concentrated

Types of hot spots showing

locations with high crime levels

Types of hot spots showing street

segments where crime 

is concentrated

Things that are particularly

attractive for theft

Geographic concentrations 

of crime

2, 24, 29

29

25, 28

10, 19, 36, 38, 40, 41

23

23

23

18, 28, 29, 31

3, 5, 16, 17, 18, 23, 48, 55
GLOSSARY AND INDEX

Term Definition Step

Hypothesis

Impact evaluation

Inner quartile range 

Input 

Intervention

Manager

Mean

Median

Mode 

Moving average

Near repeats

An answer to a question about a

problem that can be true or false,

and may or may not be supported

by evidence

A research study to determine if

the response changed the problem

The upper and lower bounds of the

50% of the cases centered on 

the median

Resources used in a response

The response being applied to a

problem (also called a treatment or

response - see Response)

A person who has some

responsibility for controlling

behaviour in a specific location

A measure of central tendency,

also known as the arithmetical

average, calculated by summing

the values for all the cases and

dividing the sum by the number of

cases. Useful for ratio data and

symmetrical distributions

A measure of central tendency that

divides the cases into two equal

groups, half below the median

value and half above

A measure of central tendency that

shows the value that the largest

number of cases possesses

A method for reducing random

fluctuation in a time series by

recomputing the value for every

data point based on the average of

preceding time periods 

(see Smoothing)

See Virtual repeats

20, 50

46

22

46

4, 7, 11, 20, 35, 40, 44, 45, 46,

47, 48, 49, 50, 51, 52

5, 8, 24, 28, 30, 33, 38, 40, 58

22

22

22

26, 52

29
GLOSSARY AND INDEX

Crime Analysis for Problem Solvers in60 small steps

Term Definition Step

Nodes

Nominal Scale 

Odds Ratio 

Offender

Offenders, repeat

Opportunity

Ordinal Scale

Outcome 

Packaging 

Paths

Perceptions, offenders'

Destination places such as home,

work, shopping, entertainment,

and school (see Paths)

Values only name and cannot 

be ranked

A measure of association between

two characteristics; useful when a

case-control study is used

A person who commits a crime or

act of disorder

People who commit many crimes

or acts of disorder (see Wolf)

Short for "crime opportunity

structure" and meaning the

physical and social arrangements

that make crime possible

A measurement scale in which

values can be ranked but no other

mathematical process can be

applied to them

The impact of the response on 

the problem

The lines and labels used in tables

and figures (see Content). Small

amounts are needed to help

interpret content, but large

amounts obscure content

Routes connecting nodes

How offenders view situations and

prevention measures

16

22

33

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,

13, 14, 15, 16, 17, 18, 21, 22, 28,

29, 30, 31, 34, 35, 36, 37, 39, 40,

41, 42, 43, 44, 46, 48, 49, 50, 52,

54, 58

3, 18, 30

9, 12, 38, 44, 48, 50

22

11, 33, 37, 46, 54

56, 57

16

11, 34
GLOSSARY AND INDEX

Term Definition Step

Place

POP

POP Guides

Problem analysis triangle

Problem-Oriented Policing

Process evaluation

Provocations

p-value

Random fluctuations

Range 

A very small area, such as an

address, street corner, or block face

(see Crime triangle, den)

See Problem-Oriented Policing

Summaries of research and

practice dealing with specific

problems and recommending

particular responses. Available

from www.popcenter.org 

and www.cops.usdoj.gov 

A graphic showing the six principal

elements of routine activity theory

- offenders, handlers,

targets/victims, guardians, places,

and managers - and used to

organized the analysis of problems 

Policing that changes the

conditions that give rise to

recurring crime problems, and does

not simply rely on responding to

incidents as they occur or

forestalling them through

preventive patrols

Assessing how a response 

was implemented

Physical designs or the way places

are managed that 

provoke misconduct

The probability that the difference

between two sets of statistics is

due to randomness (see

Significance test)

Short-term changes in problems

caused by a large number of very

small effects

A measure of dispersion showing

the minimum and maximum value

in a distribution

8, 12, 13, 17, 18, 20, 27, 30, 32,

38, 39, 40, 48

4, 5, 6, 8, 14, 19, 46

3, 19

8, 16

1, 3, 4, 5, 6, 7, 11, 15, 19, 21, 28,

38, 55, 60

46, 47, 55

34, 38, 42, 54

53

26, 53

22, 25
Crime Analysis for Problem Solvers in60 small steps

Rates, crime 

Ratio Scale

Regression to the mean

Response

Response group

Results 

Risk, crime

SARA

Scanning

The ratio of crimes to targets for

an area. Used to control for

differences in the number of

targets (see Risk, crime)

A measurement scale in which

there are equal intervals between

the ranked values and a

theoretically meaningful zero. Any

mathematical procedure can be

used on date measured on a 

ratio scale

The tendency for abnormal high or

low levels of crime to move back

to their normal levels

The third stage in the SARA

process involving the development

and implementation of an

intervention designed to reduce a

problem. Also a term for the

preventive treatment or

intervention being applied (see

Intervention or Treatment)

People or places receiving

prevention, in contrast to 

control group

Activities accomplished in 

a response

The chance a target will be

involved in a crime

An acronym for the problem

solving process (see Scanning,

Analysis, Response,

and Assessment)

The first stage in the SARA

process, involving problem

identification, verification,

and classification

9, 17, 20, 24, 26, 27, 28, 32, 37,

42, 44, 49, 51

22

47, 52

2, 4, 5, 6, 7, 14, 15, 17, 19, 20,

21, 23, 26, 29, 35, 36, 37, 38, 39,

40, 44, 45, 46, 47, 48, 49, 50, 51,

52, 53, 54, 55, 58, 60

47

46

6, 16, 17, 18, 20, 21, 23, 26, 27,

28, 29, 31, 33, 34, 38, 39, 41

7, 21

1, 7, 14, 16, 18, 38, 54

Term Definition Step

GLOSSARY AND INDEX
Scripts

Significance level

Significance test

Situational Crime Prevention

Smoothing

Standard Deviation 

Standard model

Target

Targets at risk

Temporal clustering

Time-window effect

Standard actions carried out in a

particular order by offenders to

commit crimes

A threshold below which one

rejects the possibility that the

difference between two sets of

statistics is due to randomness.

Often, .05 (or 5%) is the rejection

threshold (see Significance test)

A statistical procedure used to

determine whether the difference

between two groups of numbers is

due to randomness

The science of reducing

opportunities for crime

Removing random fluctuations

from a time series by using a

moving average 

(see Moving average)

A common measure of spread

useful for symmetrical distributions

and ratio data.

Policing that relies primarily on the

use of patrolling, rapid response,

and follow-up investigations to

prevent crime

The person or thing an offender

attacks, takes, or harms 

(see Victim)

Persons or things vulnerable to

being attacked, taken, or harmed

Concentration of crime over 24

hours (See Acute, Diffused, and

Focused temporal clustering)

The underestimation of repeat

victimization due to using a set

time period

35, 36

53

53

1, 13, 16, 34, 38, 41, 54

26, 52

22, 53

3

2, 8, 10, 12, 13, 14, 15, 16, 17,

20, 23, 25, 26, 27, 28, 29, 30, 31,

34, 35, 38, 39, 41, 44, 47, 48, 49,

52, 54, 58

26, 27

25

29

Term Definition Step

GLOSSARY AND INDEX
Crime Analysis for Problem Solvers in60 small steps

Treatment

Treatment area

Treatment group

Trend

Uncontrolled case study 

Victim

Victim, repeat

Victimization, repeat

Virtual repeats

Wolf (ravenous) problems

See Response or Intervention

Areas receiving the response in

contrast to control areas 

(see Response group)

See Response group

A steady increase, decrease, or

stable level of crime over some

period of time

A comparison of troublesome

persons, places, times, or events

without examining similar

untroublesome ones. The results of

such a study are often 

highly misleading.

A human target or the owner of

stolen goods or damaged property

(see Target)

A person or place with multiple

crimes or acts of disorder (see

Duck)

The process leading to 

repeat victims

Victimization of targets that are

very similar, though not identical

(as in the case of repeat victims or

places). Also called 

"near" repeats

Problems characterized by

substantial involvement of repeat

offenders (see Crime triangle).

Occurs when offenders are able to

locate temporarily vulnerable

targets and places

48, 49, 51

48, 51

49, 51

2, 20, 22, 26, 47, 49, 52, 57

32

1, 2, 4, 6, 8, 10, 14, 15, 16, 18,

21, 22, 23, 25, 28, 29, 30, 31, 33,

34, 35, 36, 37, 38, 42, 44, 46, 47,

48, 54, 55

18, 23, 28, 29

8, 28, 29, 30, 33, 38, 46

29

8, 15

Term Definition Step

GLOSSARY AND INDEX

FOR MORE INFORMATION:

U.S. Department of Justice

Office of Community Oriented Policing Services

1100 Vermont Avenue, N.W.

Washington, D.C. 20530

To obtain details on COPS programs, call the

COPS Office Response Center at 800.421.6770

Visit COPS Online at the address listed below.

www.cops.usdoj.gov

e01052683 Created Date: August 8, 2005

ISBN: 1-932582-52-5