Gary Cordner, Ph.D.

Academic Director 

Education and Training Section

Baltimore Police Department

NATIONAL INSTITUTE OF JUSTICE

EVIDENCE-BASED POLICING

IN 45 SMALL BYTES

U.S. Department of Justice

Office of Justice Programs

National Institute of Justice

May 2020
U.S. Department of Justice

Office of Justice Programs

810 Seventh St. N.W.

Washington, DC 20531

David B. Muhlhausen, Ph.D.

Director, National Institute of Justice

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The National Institute of Justice is the research, development, and evaluation agency of the U.S. Department of Justice. NIJ’s 

mission is to advance scientific research, development, and evaluation to enhance the administration of justice and public safety.

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The author prepared this paper with support from the National Institute of Justice, Office of Justice Programs, U.S. Department of 

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Evidence-Based Policing in 45 Small Bytes i

Contents

Introduction....................................................................................................................... iii

Evidence-Based Policing.................................................................................................. 1

What Is Evidence-Based Policing?................................................................................. 2

Practical EBP: Data, Analysis, Research, and Evidence................................................. 4

The Limits of EBP............................................................................................................ 6

EBP vs. Intelligence-Led, Problem-Oriented, and Community-Oriented Policing.......... 8

Effective Policing............................................................................................................. 11

The Bottom Line(s) of Policing...................................................................................... 12

Reducing Serious Crime ............................................................................................... 14

Holding Offenders to Account ...................................................................................... 16

Maintaining Safety and Order ....................................................................................... 18

Reassuring the Public ................................................................................................... 20

Providing Quality Services ............................................................................................ 22

Using Force and Authority Fairly and Effectively .......................................................... 24

Using Financial Resources Fairly, Efficiently, and Effectively........................................ 26

Police Legitimacy.......................................................................................................... 28

Measuring External Conditions...................................................................................... 31

Crime and Disorder....................................................................................................... 33

Traffic Crashes .............................................................................................................. 35

Vulnerable People ......................................................................................................... 37

Known Offenders .......................................................................................................... 39

Fear of Crime ................................................................................................................ 41

Citizen Complaints........................................................................................................ 43

Client Satisfaction ......................................................................................................... 45

Public Trust ................................................................................................................... 47

Measuring Internal Conditions....................................................................................... 49

Officer Safety, Health, and Wellness ............................................................................. 51

Employee Attitudes, Knowledge, Skills, and Talents .................................................... 54

Discipline and Grievances............................................................................................. 56

Applicants and New Hires............................................................................................. 58

Training.......................................................................................................................... 60
ii National Institute of Justice | NIJ.ojp.gov

Measuring Performance ................................................................................................. 63

Arrests, Citations, Stops, and Searches ....................................................................... 65

Use of Force and Pursuits............................................................................................. 68

Public Contacts, Community Engagement, and Problem Solving ............................... 70

Response Time ............................................................................................................. 72

Crime Clearances and Judicial Outcomes.................................................................... 74

Civil Suits and Judgments ............................................................................................ 76

Identifying and Analyzing Problems .............................................................................. 79

Analyzing Bottom-Line Outcomes ................................................................................ 81

Analyzing External Conditions ...................................................................................... 84

Analyzing Internal Conditions ....................................................................................... 86

Analyzing Performance ................................................................................................. 88

Evaluating Practices and Testing Alternatives ............................................................. 91

Process and Outcome Assessment.............................................................................. 93

Evaluating Current Practices......................................................................................... 96

Testing New Practices................................................................................................... 99

Experiments and Quasi-Experiments ......................................................................... 102

Nonexperimental Evaluations ..................................................................................... 105

Using Evidence.............................................................................................................. 109

Finding and Weighing Evidence.................................................................................. 110

Putting Evidence to Use.............................................................................................. 113

Creating an Evidence-Based Agency ......................................................................... 115

Continuous Improvement............................................................................................ 118

Suggested Readings ..................................................................................................... 121

Valuable Resources....................................................................................................... 129
Introduction

T

his guidebook presents a practical framework for understanding evidence-based 

policing (EBP). The framework is practical in the sense that it is understandable, 

feasible, and directly tied to making policing more effective. In other words, it isn’t 

about collecting data for its own sake, or about doing research for its own sake. Rather, it 

is about serving and protecting the public as effectively as possible.

That said, this EBP framework is demanding because the police mission is demanding.1

The framework identifies data that should be collected, analyses that should be 

conducted, and research that should be carried out — all for the purpose of making 

policing better. Improving policing depends on producing and then using the best 

available evidence when making decisions, developing policies, and designing programs 

and practices.

The framework is presented in 45 small “bytes.” The number is arbitrary, but it illustrates 

the fact that policing is a broad function in a society that expects a lot from the police. 

The people who manage police organizations need a lot of information in order to know 

how well (or how poorly) things are going and what problems need attention. In addition, 

the public and political leaders want information by which to judge how well their police 

are performing, as reflected in the growing emphasis on transparency and accountability.

Byte 1 dives right into the question, “What is evidence-based policing?” Before getting to 

that, three comments are in order:

1. The guidebook is mainly written with chiefs, sheriffs, and commanders in mind 

because the people in charge of police agencies are most responsible for making 

them as effective as possible. They have the strongest need for data, analysis, 

research, and evidence to help them make decisions that will produce the best 

possible organizational results. They have to answer to the public and governing 

officials, and they are the ones who might lose their jobs if things don’t go well. When 

a councilperson asks, “Chief, how are we doing?,” an off-the-cuff, vague response 

may not suffice. The framework presented here will help the chief respond with a welldocumented, full-fledged answer.

 Although the guidebook is primarily aimed at high-ranking law enforcement officials, it 

should be useful to a wide range of others. Within police agencies, middle managers, 

supervisors, and officers all make decisions and need to be as well-informed as 

possible. Also, civilian law enforcement personnel, especially analysts and planners, 

Evidence-Based Policing in 45 Small Bytes iii

1

 The terms police and policing are used throughout this guidebook for simplicity but are intended to refer to all kinds of 

general-purpose law enforcement agencies, including sheriff’s departments and state police.
are often the ones most directly involved in collecting and analyzing data and 

evaluating programs. Outside of police, city managers, local and state elected 

officials, public interest groups, and concerned citizens all have a role in holding 

police agencies accountable; they will all find the framework helpful in judging how 

effectively their police are performing.

2. The guidebook emphasizes what data, analysis, and research capabilities police 

agencies should have and explains why those capabilities are important, with 

examples. However, it does not go into as much detail about how to carry out all the 

various data collection, analysis, and research tasks required to implement EBP. This 

is partly because that would take multiple books and courses, and partly because 

many police agencies already have personnel with the necessary knowledge and 

skills. What seems most important is to articulate a clear and workable framework that 

shows how things can fit together logically and contribute to more effective policing.

3. This guidebook does not distinguish between large and small police agencies. At first 

glance, the EBP framework and its 45 bytes might seem tailored for large agencies 

only, but they aren’t. As an example, both large and small agencies need to know 

about crime patterns and hot spots — it just takes more work and a more formal 

process to identify them in a bigger jurisdiction. Similarly, any chief or sheriff needs to 

have a good understanding of officer morale, stress, and turnover. In a large agency, 

that is likely to require formal data collection and analysis, whereas, in a small agency, 

such conditions might be readily observed. The what and why of the framework are 

equally applicable to small and large agencies; they just differ in how they achieve the 

level of information and evidence needed to make well-informed decisions.

The EBP framework presented in this guidebook is meant to stand on its own and be 

easily understood. As such, references and footnotes are kept to a minimum, but a 

small number of suggested readings are identified throughout the guidebook for readers 

interested in source documents, important studies, and key thinkers. 

One last word: This introduction is longer

than many of the 45 bytes, so do not despair.

iv National Institute of Justice | NIJ.ojp.gov
SUGGESTED

READING

Tilley, N., and G. Laycock. 2016. 

“Engineering a safer society.” 

Public Safety Leadership: 

Research Focus 4 no. 2. Manly, 

NSW: Australian Institute of 

Police Management. https://

www.aipm.gov.au/sites/default/

files/header/Research-FocusVol-4-Iss-2-Engineering.pdf. 

Evidence-Based Policing in 45 Small Bytes 1

SECTION 1:

Evidence-Based Policing

T

he four bytes in this first section explain what evidence-based policing (EBP) is, 

and what it isn’t. They emphasize that it is about using data, analysis, and research, 

but it isn’t about dismissing or marginalizing police experience and professional 

judgment. EBP is simply about informing police decisions and practices with the best 

available knowledge — much as doctors, nurses, engineers, counselors, teachers, and 

other professionals are informed by their own bodies of scientific information.

It is important to recognize that doctors and engineers, despite working in welldeveloped professions, usually cannot just “look up” or “calculate” the right answer for 

each situation they face. Rather, they have to draw on their experience and judgment — 

the skills of their craft as well as whatever scientific knowledge may be applicable — to 

diagnose and respond to the situation. Often, careful trial and error is still required before 

a satisfactory outcome is achieved. The same is true with EBP.

To put it another way, there isn’t an app, and there isn’t going to be an app.2 The 

complexity and unpredictability of policing guarantee that it won’t all boil down to an 

algorithm. But there are lots of reasons to believe that making policing as evidence-based 

as possible will make it more effective, thus contributing to a safer and more just society.

Evidence-Based Medicine

“The mission of ‘evidence-based medicine’ is surprisingly recent. Before its arrival, much of medicine 

was based on clinical experience. Doctors tried to figure out what worked by trial and error, and they 

passed their knowledge along to those who trained under them.”

“The benefits of evidence-based medicine, when properly applied, are obvious. We can use test 

characteristics and results to make better diagnoses. We can use evidence from treatments to 

help people make better choices once diagnoses are made. We can devise research to give us 

the information we are lacking to improve lives. And, when we have enough studies available, we 

can look at them together to make widespread recommendations with more confidence than we’d 

otherwise be able.”

Source: Carroll, A.E. 2017. “What we mean when we say evidence-based medicine.” New York Times (December 27).

2

 Actually, there is an evidence-based policing app at http://www.evidence-basedpolicing.org. It provides a great deal 

of useful information but doesn’t cover all of the “bottom-line outcomes” of policing or present the information in the 

kind of broad, systematic framework used in this guide.
2 National Institute of Justice | NIJ.ojp.gov

BYTE 1

What Is EvidenceBased Policing?

Although the term evidence-based policing (EBP) has become well known, we need 

to be clear about how it is being used. First, it is important to understand that it 

refers to scientific evidence, not evidence in the legal or investigative sense. EBP 

is the policing parallel to evidence-based medicine and fits within the broader categories 

of evidence-based practice, evidence-based decision-making, evidence-based 

management, and so forth.

Lawrence Sherman is credited with coining the term evidence-based policing in a 1998 

Police Foundation paper, arguing that “police practices should be based on scientific 

evidence about what works best.”3 Similarly, Cynthia Lum and Chris Koper recently 

asserted that “research, evaluation, analysis, and scientific processes should have a 

‘seat at the table’ in law enforcement decision making about tactics, strategies, and 

policies.”4 Their “seat at the table” analogy helps clarify that the best available evidence 

should inform policing while acknowledging that there are other seats at the table, too — 

experience, judgment, and law, for example.

Here’s how evidence-based policing is defined in this guidebook:

Using data, analysis, and research to complement experience and professional 

judgment, in order to provide the best possible police service to the public.

This definition says that law enforcement agencies and personnel should be informed 

by the best available scientific evidence as they go about identifying and understanding 

issues and problems, choosing responses, making decisions, setting policies, allocating 

resources, and enhancing employees’ well-being. Looked at this way, EBP is a nobrainer. It would be foolish and harmful for police to utilize practices that don’t work — 

and unethical to knowingly disregard more effective ones.5

 It is safe to say that every 

right-minded law enforcement official always makes what they believe are the best 

decisions.

3

 Sherman, L.W. 1998. “Evidence-based policing.” Ideas in American policing. Washington, DC: Police Foundation, 2. 

https://www.policefoundation.org/publication/evidence-based-policing. 

4

 Lum, C., and C.S. Koper. 2017. Evidence-based policing: Translating research into practice. Oxford: Oxford University 

Press, 3-4.

5

 Johnson, J.P. 2016. “A Hippocratic oath for policing.” Blog post. Washington, DC: National Police Foundation. 

https://www.policefoundation.org/a-hippocratic-oath-for-policing. 
SUGGESTED

READING

Lum, C., and C.S. Koper. 2017. 

Evidence-based policing: 

Translating research into 

practice. Oxford: Oxford 

University Press.

Evidence-Based Policing in 45 Small Bytes 3

What EBP suggests, however, is that sometimes police agencies do things a certain 

way because “we’ve always done it that way,” without any particular evidence that this 

is the best way. Likewise, law enforcement agencies don’t always devote much energy 

toward analyzing and evaluating their practices in order to figure out just how effective (or 

ineffective) they really are. Thus, it is quite possible that policing isn’t as evidence-based 

as it could be, and to the extent that is true, police agencies aren’t as effective as they 

could be.

Which is not to say that everyone in policing has to don a lab coat and become a 

research scientist. The approach to EBP taken in this guidebook is practical, reasonable, 

and balanced. For the most part, it’s not rocket science. It is about how to make policing 

more effective.

Evidence-Based Policing in Eau Claire, Wisconsin

The Eau Claire Police Department did a study testing the impact on back pain of the traditional duty 

belt versus the load-bearing vest. The police partnered with local researchers to carry out the sixmonth study in which 30 officers rotated between the two equipment options. Participants reported 

less pain wearing the vests, so the department made the switch. Besides the relief for officers, a 

deputy chief noted, “Lost time due to injury or medical cost related to back injuries are significant 

and the entire community shares that cost.”

Source: Adapted from Schwieters, B. 2018. “Study aims to improve health of local police officers.” WEAU News (October 30).
4 National Institute of Justice | NIJ.ojp.gov

BYTE 2

Practical EBP: Data, 

Analysis, Research, 

and Evidence

S ome versions of evidence-based policing (EBP) put all their emphasis on 

determining “what works,” which leads them to push experimental research 

(randomized controlled trials, or RCTs) to the near exclusion of everything else. 

That approach has the virtue of what researchers call internal validity: A carefully done 

experiment produces the most valid conclusions about causation — in other words, 

whether A caused B (e.g., whether a particular patrol strategy caused an observed 

decrease in street crime).

Experiments are quite useful in policing, but the perspective on EBP needs to be broader, 

for several important reasons:

1. Effective policing and police administration depend on knowing much more than just 

“what works.” Information is needed to identify problems, analysis is needed to spot 

patterns and trends, and research is often needed to figure out why a new program 

wasn’t implemented correctly — not just that it didn’t work.

2. An important aspect of evidence-based policing is using the best available evidence. 

EBP is as much about properly utilizing research (and data and analysis) as it is about 

doing research. 

3. A disadvantage of experimental studies (as well as quasi-experimental studies) is that 

their external validity is generally limited or unknown. Consequently, for places other 

than where the experiment was conducted, it is usually a guess whether the study’s 

results would be the same in one’s own jurisdiction.

4. Experimental studies can be fairly complicated, expensive, and time-consuming. They 

aren’t always practical for many law enforcement agencies, although rapid RCTs like 

the ones supported by New York University’s BetaGov are making it easier to study a 

research question quickly and efficiently without sacrificing experimental rigor.

The broad EBP framework presented in this guidebook rests on four equally important 

components — data, analysis, research, and evidence. A law enforcement agency 

wanting to be more evidence-based needs all four components:

• Data are needed about a wide array of conditions — both in the community and 

inside the agency — so that issues and problems can be identified and performance 

can be monitored.
SUGGESTED

READING

Knutsson, J., and L. Tompson, 

eds. 2017. Advances in 

evidence-based policing. 

London: Routledge.

Evidence-Based Policing in 45 Small Bytes 5

• Analysis is needed to figure out why issues and problems are occurring, and to 

identify patterns and trends that the agency needs to address.

• Research is needed to evaluate the effectiveness of the agency’s programs and 

strategies, including ongoing practices as well as newly implemented ones. Research 

is also needed any time an important question comes up and the answer can’t simply 

be Googled.

• Evidence is derived from the agency’s own data, analysis, and research as well as 

studies done elsewhere. A law enforcement agency needs to cultivate its ability to find 

and produce evidence, weigh its credibility and relevance, and then use the evidence 

appropriately to best inform decisions and practices.

Most of this guidebook, specifically Sections 3-8, is organized around these four EBP 

components — data, analysis, research, and evidence.

A Broad Perspective on Evidence-Based Policing

“It is clear ... that increased collection and analysis of information — that is, evidence — has a 

crucial role to play in informing improvements in policing and that it can do so in a variety of ways. It 

should also be clear that it would be counterproductive to confine one’s sources of evidence to any 

specific form or to that collected using any specific method. Finally ... there is scope for greater use 

of evidence at diverse points in the education and training of police officers, in the conduct of their 

work, in original research and in reviewing and learning from failures. What we are suggesting is a 

very broad-based agenda for the injection of research-based evidence into policing and its further 

development within the profession.”

Source: Tilley, N., and G. Laycock. 2017. “The why, what, when and how of evidence-based policing.” In J. Knutsson and 

L. Tompson, eds., Advances in evidence-based policing. London: Routledge, 23.
6 National Institute of Justice | NIJ.ojp.gov

BYTE 3

The Limits of EBP

B efore getting any deeper into evidence-based policing (EBP) and its components — 

data, analysis, research, and evidence — it is important to reiterate and emphasize 

that research and science don’t have all the answers for policing and are not the 

only sources of bona fide knowledge. Police decision-makers have to balance research 

and data with experience and professional judgment.

The issue of context was mentioned in byte 2 — it is hard to know whether the results 

of a study done in one place are transferable elsewhere. Another limitation is that 

science never “proves” anything. Rather, it tests theories (formal explanations about how 

something works) by confirming or disconfirming hypotheses, a fancy way of saying that 

all scientific knowledge is tentative. Even principles and “facts” that are relatively wellestablished are periodically subjected to further testing, and sometimes overturned.

A more philosophical issue arises because policing is a function of a government that is 

“of the people,” not “of data” or “of science.” As a society, we choose to have guilt or 

innocence decided by a judge or jury, not a computer algorithm. Science and technology 

continually advance, but “we the people” are the ones who decide how to use it. For 

example, brain scanning may someday accurately detect human deception, but whether 

and how police are allowed to use that technology to identify liars will be determined by 

public opinion, politics, and the U.S. Constitution — not research. 

One further complication is that police agencies have to juggle competing interests, 

priorities, and outcomes. A study may determine that a particular strategy is more 

effective than another at reducing crime, but police must also consider its effects on 

fear of crime, public trust, efficient use of resources, and equitable use of force and 

authority — not to mention key values such as legality, transparency, and accountability. 

Researchers often have the luxury of focusing their studies on one isolated outcome (the 

“dependent variable”), but law enforcement executives have to juggle multiple outcomes, 

all of which matter.

Not surprisingly, law enforcement needs to follow the middle way. Using data, analysis, 

and research to inform policing will pay huge dividends in increased effectiveness and 

better public service. At the same time, everyone needs to recognize that police policies 

and practices are inevitably influenced by law, values, politics, and public opinion. One 

of the responsibilities of police leaders is drawing on wisdom and experience to make 

their agencies as evidence-based as possible, given the multitude of challenges and 

considerations that inevitably constrain their real-world decision-making.
SUGGESTED

READING

Fleming, J., and R. Rhodes. 

2017. “Experience is not 

a dirty word.” Policy & 

Politics Journal Blog. https://

policyandpoliticsblog.

com/2017/06/20/experienceis-not-a-dirty-word. 

Evidence-Based Policing in 45 Small Bytes 7

Science or Craft?

“By itself, evidence-based knowledge is not enough. We need the partisans arguing for scientific 

evidence but we need also other types of knowledge. Craft knowledge, political knowledge, and 

research-based knowledge, all warrant a place at the table. These several strands need to be woven 

together. Craft knowledge not only needs to be treated as evidence in this weaving, but we need to 

recognize that it provides also the basis for choosing between the available sources of evidence.”

Source: Fleming, J., and R. Rhodes. 2017. “Experience is not a dirty word.” Policy & Politics Journal Blog. https://

policyandpoliticsblog.com/2017/06/20/experience-is-not-a-dirty-word. 
8 National Institute of Justice | NIJ.ojp.gov

BYTE 4

EBP vs. IntelligenceLed, Problem-Oriented, 

and CommunityOriented Policing

I

t is necessary to emphasize that evidence-based policing (EBP) is not the 

latest hyphenated strategy of policing; in fact, it is not a policing strategy at all. 

Consequently, it will not replace intelligence-led policing (ILP), problem-oriented 

policing (POP), community-oriented policing (COP), or any other policing strategy. Rather, 

EBP can help a law enforcement agency identify which strategy might be the best fit 

for its situation, help the agency implement that strategy, and then help determine how 

effectively the strategy is working.

ILP depends heavily on data to identify priority targets (offenders, locations, behaviors) 

most deserving of police attention. Thorough analysis helps uncover crime patterns, 

connections between offenders, and other dynamics that can help police figure out 

how to intervene most effectively. The driving principle of ILP is that an agency’s 

actions should always be guided, day by day if not hour by hour, by the latest and best 

information (intelligence) about crime and offenders in its jurisdiction.

POP relies on (1) data to identify emerging crime and disorder problems; (2) analysis to 

describe the problems and figure out why they are occurring; (3) implementation of tailormade responses; and (4) assessment (evaluation) to determine whether the problems 

have been reduced, and if not, why not. The selection of responses to a problem (after 

it has been analyzed) should be wide-ranging and should draw on both evidence and 

previous experience from within the agency and elsewhere. 

COP is generally perceived as less data-driven and analytically based than intelligenceled or problem-oriented policing, but where it really differs is in its priority outcomes. 

COP puts its greatest emphasis on improving police-community relationships, reducing 

fear of crime, and providing quality services — not to the exclusion of reducing crime 

and disorder but on the premise that increasing public trust and cooperation will lead to 

longer-lasting decreases in crime. Often overlooked is that data and analysis are needed 

to correctly identify a jurisdiction’s particular public trust and police-community relations 

issues and problems. Also, research is needed to determine whether COP initiatives that 

are undertaken succeed in making those issues and problems better, and if not, why not.
SUGGESTED

READING

Sparrow, M. 2016. Handcuffed: 

What holds policing back, and 

the keys to reform. Washington, 

DC: Brookings Institution.

Evidence-Based Policing in 45 Small Bytes 9

The takeaway is that there’s no “versus” between EBP and any of these, or other, 

policing strategies. EBP represents the most logical and rational approach for a law 

enforcement agency to adopt as it considers, implements, evaluates, and refines its 

strategies of policing, whatever they are.

POP and EBP

“Problem-oriented policing and EBP ... are prescriptions for figuring out what to do, not prescriptions 

for what to do. This is important because determining whether POP and EBP are viable policing 

approaches depends not on whether their application reduces crime and disorder directly, but on 

whether they enable police to figure out how to handle their business effectively and fairly.”

Source: Scott, M. 2017. “Reconciling problem-oriented policing and evidence-based policing.” In J. Knutsson and L. Tompson, 

eds., Advances in evidence-based policing. London: Routledge, 29.

SUGGESTED

READING

Lum, C., and D. Nagin. 2015. 

“Reinventing American 

policing: A seven-point 

blueprint for the 21st century.” 

Translational Criminology (Fall): 

2-5, 11. http://cebcp.org/

wp-content/TCmagazine/TC9-

Fall2015. 

Evidence-Based Policing in 45 Small Bytes 11

SECTION 2:

Effective Policing

R emember, the purpose of evidence-based policing (EBP) is to make policing as 

effective as possible. The methods of EBP — data, analysis, and research — are 

the methods of science, but the point of EBP is to use these methods to achieve 

real-world practical results, not to do science for its own sake.

A word about effectiveness: Organizations and systems of all kinds are expected to 

operate in an effective manner. By definition, an activity is effective to the extent that 

it achieves its intended outcomes. To oversimplify just a bit, a company is effective if 

it maximizes its profit (its “bottom line”), and a sports team is effective if it finishes in 

first place. 

One or both of two errors are common when thinking about police effectiveness: 

(1) mistaking an output, such as number of arrests, for an outcome, such as reducing 

crime, and (2) choosing one outcome while ignoring others. Focusing on outputs is 

understandable but insufficient, since the output (e.g., number of arrests) may or may 

not produce the outcome (e.g., reducing crime) that really matters. Focusing on only one 

outcome is risky if there are multiple outcomes that matter, which is usually the case for 

government agencies, and always true for police organizations.

Here, in Section 2, this guidebook identifies and explains the outcomes of policing — 

emphasis on the plural outcomes because policing does, in fact, have a multifaceted 

bottom line. Policing and police administration would be a lot simpler if there was a single 

important outcome, but there isn’t.

Outputs vs. Outcomes

“The desired outcomes of policing differ from the observed outputs of a police organization in 

that desired outcomes occur farther down a chain of causation than organizational outputs. They 

are more distant in space and time from the police activities that occur right at the boundary of 

the organization. Organizational outputs are the specific things that the police do; desired social 

outcomes are the valuable results that occur in society as a consequence of what the police do.”

Source: Moore, M.H., and A. Braga. 2003. The “bottom line” of policing: What citizens should value (and measure!) in police 

performance. Washington, DC: Police Executive Research Forum, 3. http://www.policeforum.org/assets/docs/Free_Online_

Documents/Police_Evaluation/the%20bottom%20line%20of%20policing%202003.pdf. 
12 National Institute of Justice | NIJ.ojp.gov

BYTE 5

The Bottom Line(s) 

of Policing

Since at least the 1960s, experts and commentators have suggested alternative 

ways of expressing the true purpose or ends of policing. Mark Moore and Anthony 

Braga produced a practical and useful framework in 2003 that incorporates seven 

dimensions of the policing “bottom line.” This framework is favored because it seems to 

capture the key outcomes that people expect the police to try to achieve, without being 

too detailed and complicated. The seven dimensions, or outcomes, are as follows:

• Reducing serious crime 

• Holding offenders to account 

• Maintaining safety and order 

• Reassuring the public 

• Providing quality services 

• Using force and authority fairly and effectively 

• Using financial resources fairly, efficiently, and effectively.

Visible patrolling, responding to emergency and nonemergency calls, enforcing the law, 

taking reports, investigating crimes, checking into suspicious situations, interacting 

with people — these are the means and methods of policing. They are not ends in 

themselves, but they are important aspects of police performance that are intended to 

achieve the seven bottom-line outcomes listed above, which include preventing crime, 

solving crimes, helping people feel safe and secure, and delivering services to people 

who need them.

The importance of this framework, a kind of “balanced scorecard,” cannot be overstated. 

The whole point of evidence-based policing is to use data, analysis, and research to 

make policing more effective — i.e., to help achieve the seven dimensions of the policing 

bottom line as completely as possible. 

An alert reader might wonder, what about police legitimacy? Legitimacy is best 

understood as the ultimate desired end of policing — when people are satisfied that 

the police are capable, trustworthy, and performing as effectively as possible. In other 

words, the legitimacy of the police institution is best protected and enhanced when the 
SUGGESTED

READING

Moore, M.H., and A. Braga. 

2003. The “bottom line” of 

policing: What citizens should 

value (and measure!) in police 

performance. Washington, 

DC: Police Executive 

Research Forum. http://www.

policeforum.org/assets/docs/

Free_Online_Documents/

Police_Evaluation/the%20

bottom%20line%20of%20

policing%202003.pdf. 

Evidence-Based Policing in 45 Small Bytes 13

police are as effective as possible at reducing crime, holding offenders accountable, 

maintaining safety and order, providing reassurance, delivering quality services, and 

using force, authority, and financial resources fairly and efficiently.

The next few bytes address these bottom lines of policing, and then police legitimacy, 

one by one.

Balanced Scorecard

“The ‘balanced scorecard’ [in the private sector] includes measurements that focus on the efficiency 

of operational methods and the quality of customer and employee relations, rather than single 

measures of financial performance. They focus on these measures because the measures help them 

look behind their financial performance to find the reasons for their success, and keep them focused 

on the things they need to do to ensure their success in the future. Presumably, there are all kinds of 

complicated, unknown tradeoffs among these different measures. But the important thing about each 

of these measures is we know in which direction we would like them to move.”

“Following the lead of the balanced scorecard in the private sector, I think that we could use the 

seven dimensions of policing as a ‘public value scorecard’ with which citizens could monitor 

police performance. The ideal performance measurement for a police department does not record 

performance on only one dimension, but reliably measures multiple, nonfinancial dimensions of 

performance.”

Source: Moore, M.H., and A. Braga. 2003. The “bottom line” of policing: What citizens should value (and measure!) in police 

performance. Washington, DC: Police Executive Research Forum, 30. http://www.policeforum.org/assets/docs/Free_Online_

Documents/Police_Evaluation/the%20bottom%20line%20of%20policing%202003.pdf. 
14 National Institute of Justice | NIJ.ojp.gov

BYTE 6

Reducing Serious Crime

Right away, most people would think of reducing or controlling crime as a main 

purpose of policing. This purpose was emphasized long ago in the well-known 

Peelian principle that “the test of police efficiency is the absence of crime and 

disorder, not the visible evidence of police action in dealing with it.” In other words, what 

matters most is less crime and victimization, not more arrests and stops. It follows that 

preventing crime is preferable to merely reacting properly after it occurs.

Most of the focus of evidence-based policing has been on conducting studies to 

determine the crime-control effectiveness of police strategies and programs. The first 

major study, published in 1974, was the Kansas City Preventive Patrol Experiment.6

Since then, many experimental and quasi-experimental studies have been conducted. 

The most consistent finding has been that policing efforts that are targeted — whether at 

locations (hot spots), specific categories of crime, or prolific offenders — tend to be more 

effective at reducing crime than efforts that are diffuse or generic.

A law enforcement agency should carefully track crime in its jurisdiction, not just to be 

aware of increases or decreases but also to identify specific patterns, trends, and crime 

problems — preferably sooner rather than later to prevent as many future crimes as 

possible. Accurate targeting isn’t feasible without this kind of information. Because this is 

so important, later sections of this guide focus on crime data and crime analysis.

From the standpoint of overall agency effectiveness, measuring the amount of crime is 

essential. Unfortunately, yet understandably, most agencies only have data on reported 

crime, which vastly undercounts the actual amount of crime, making it impossible to 

know the size and scope of the real crime problem. It can also distort apparent changes 

in crime if, for example, residents become more likely to report crimes that occur (which 

sometimes happens when police engage in trust-building initiatives) or are less likely to 

report them (which may happen when police staffing is low, causing longer response 

times that exceed victims’ patience). 

Another impediment to measuring crime in a meaningful way is the longstanding reliance 

on the FBI’s Uniform Crime Reporting (UCR) program. The seven UCR Part I crime 

categories were a more useful measure of crime 50 years ago than they are today. They 

do not include cybercrime or other types of fraud (no matter how big the loss), simple 

assaults (which means they do not count most domestic violence), vandalism (no matter 

6

 Kelling, G.L., T. Pate, D. Dieckman, and C.E. Brown. 1974. The Kansas City preventive patrol experiment: A summary 

report. Washington, DC: Police Foundation. https://www.policefoundation.org/wp-content/uploads/2015/07/Kelling-etal.-1974-THE-KANSAS-CITY-PREVENTIVE-PATROL-EXPERIMENT.pdf. 
SUGGESTED

READING

Weisburd, D., and M.K. 

Majmundar, eds. 2018. 

Proactive policing: Effects 

on crime and communities. 

Washington, DC: National 

Academies Press. https://

www.nap.edu/catalog/24928/

proactive-policing-effects-oncrime-and-communities. 

Evidence-Based Policing in 45 Small Bytes 15

how much damage), and many other offenses, but they do include each and every 

physical theft regardless of dollar value, such as shoplifting a pack of gum. Efforts are 

now underway to develop more meaningful crime measures, but progress is slow.

Despite these limitations, a law enforcement agency is expected to measure and report 

the level of crime in its jurisdiction so that residents can be informed and aware. Besides 

using standard existing measures, the best advice is to focus on the most serious crime, 

along with what matters most to residents. In big cities, murders and shootings often 

deserve the closest attention. Agencies have recently recognized that it is particularly 

important to count shootings, which could easily have been murders, had the bullets 

struck a vital organ or had medical attention not been effective. In a small town, by 

contrast, vandalism/criminal mischief might be the most common and costly crime and, 

therefore, one that would be important to measure, analyze, and report, even though it 

isn’t a UCR Part I crime. 

Measuring Crime

“Measuring overall levels of criminal victimization, and observing how those levels are changing 

over time, at both the city and the district level, is probably the single most important performance 

measure for police departments to collect. Currently, police departments rely heavily on reported 

crime numbers to accomplish this goal. These numbers have the great advantages of being 

inexpensive to collect, and of providing a continuous series that can be observed at citywide, 

district, and street address levels. They have the great disadvantage of revealing only the criminal 

victimization that victims and witnesses decide to share with the police. To get at the ‘dark figure of 

crime,’ one must go to victimization surveys, or to public health data systems.”

Source: Moore, M.H., and A. Braga. 2003. The “bottom line” of policing: What citizens should value (and measure!) in police 

performance. Washington, DC: Police Executive Research Forum, 38. http://www.policeforum.org/assets/docs/Free_Online_

Documents/Police_Evaluation/the%20bottom%20line%20of%20policing%202003.pdf.
16 National Institute of Justice | NIJ.ojp.gov

BYTE 7

Holding Offenders 

to Account

When crimes occur, police are expected to try to solve them. Identifying offenders, 

arresting offenders, and collecting evidence to support prosecution are all part 

of holding offenders to account. Of course, it is more directly the responsibility 

of the rest of the criminal justice system (prosecution, courts, corrections) to actually hold 

offenders accountable, but without effective police performance on the front end, little 

else happens.

Police effectiveness in holding offenders to account is important for several reasons. 

One is general deterrence, which helps reduce crime. Many offenders weigh the risk of 

getting caught, so when police are better at catching offenders and solving crimes, some 

offenders will desist from committing crimes, or at least commit fewer. A related benefit is 

specific deterrence — those offenders who get caught are deprived of the opportunity to 

commit more crimes as long as they are incarcerated or under close supervision.

Holding offenders accountable is also a service to victims and their families. Even when 

they have suffered harms that cannot really be repaired, victims often get some comfort 

from knowing that the person who offended against them was caught. In some cases, 

they may even get some compensation in the form of restitution from the offender.

More generally, victims and the larger society benefit when they see that those who 

commit crimes are held accountable. To put it another way, when the perception is that 

crime pays and offenders get away with their crimes, the public may lose confidence in 

the police, in the justice system, and in the government’s ability to protect the people. 

This can feed cynicism and weaken the social bonds that hold communities together. In 

the worst case, lack of confidence in law enforcement leads to vigilantism, when people 

feel they need to take the law into their own hands. 

Police have traditionally measured their clearance rate, which is the portion of reported 

crimes that have been solved. This is a key metric of police effectiveness that deserves 

to be tracked and reported, although the definition of “solved” is open to some 

interpretation and therefore has to be looked at carefully. Agencies usually track their 

number of arrests, especially for crimes that are typically discovered through proactive 

policing rather than reported by a victim — such as disorderly conduct, intoxicated 

driving, and drug offenses.
SUGGESTED

READING

Scott, M.S. 2017. Focused 

deterrence of high-risk 

individuals. Tempe, AZ: Arizona 

State University, Center for 

Problem-Oriented Policing. 

https://popcenter.asu.edu/

sites/default/files/spi_focused_

deterrence_pop_guide_final.pdf. 

Evidence-Based Policing in 45 Small Bytes 17

The real outcome of interest is holding offenders to account. To measure their 

effectiveness in relation to this bottom line, agencies need to look beyond identifying the 

offender and making arrests. They should also examine the degree to which their cases 

contribute to prosecutions, convictions, and appropriate sentences. This is a challenge; it 

is true that police might build a strong case only to have a witness disappear, or a victim 

recant, or a prosecutor drop the charges in return for a guilty plea to some other offense. 

Thus, the prosecution rate or the conviction rate can be deceiving. But, at the same 

time, if a police agency is making a lot of arrests that are not leading to prosecutions 

or convictions, a problem needs to be addressed, because the outcome — holding 

offenders to account — is not being achieved.

Measuring arrests, crime clearances, and judicial outcomes are all discussed in later 

sections of this guide.

Investigative Effectiveness

“The police ought to be interested in and held accountable for the quality of their investigations 

and arrests as well as for the ultimate results of these activities. By quality, I mean three somewhat 

different things: first, the professional skill the police show in developing evidence and making 

arrests; second, the extent to which their methods of investigating and arresting can stand up to legal 

scrutiny, and therefore count as a ‘good bust’; and third, the extent to which the investigation and 

arrest can be expected to produce a conviction.”

Source: Moore, M.H., and A. Braga. 2003. The “bottom line” of policing: What citizens should value (and measure!) in police 

performance. Washington, DC: Police Executive Research Forum, 42. http://www.policeforum.org/assets/docs/Free_Online_

Documents/Police_Evaluation/the%20bottom%20line%20of%20policing%202003.pdf. 
18 National Institute of Justice | NIJ.ojp.gov

BYTE 8

Maintaining Safety 

and Order

A century or more ago — before the advent of sidewalks, parking lots, indoor 

plumbing, sewer systems, and other miracles of modern infrastructure — 

sanitation and public health were among the responsibilities of police. That is no 

longer true, for the most part, but police are still expected to protect safety and order in 

public places.

Today, maintaining safety and order includes such activities as traffic and parking control, 

crowd management, event security, handling noise complaints and disorderly people, 

resolving disputes, making sure that parks are safe places for children and families, and 

intervening in crisis situations involving persons with mental illness. Although some of 

these situations can and do result in enforcement and arrest, the crimes or infractions 

involved are generally minor and police often try to handle them informally. The objective 

is to keep the peace and make it safe for people to use public spaces appropriately.

The traffic component of maintaining safety and order is a core element of policing that 

often gets overshadowed by crime control. However, the number of people who die each 

year in traffic crashes is roughly twice the number who are murdered, and hundreds of 

thousands more are injured. Making roadways safer is thus a crucial dimension of police 

performance. Less dramatic but equally important are police activities aimed at making 

streets and highways orderly, so that traffic can flow smoothly, allowing people and 

merchandise to arrive at their destinations in a timely manner.

The task of policing mass demonstrations illustrates how challenging it can be to 

maintain safety and order. The First Amendment to the U.S. Constitution guarantees “the 

right of the people peaceably to assemble, and to petition the Government for a redress 

of grievances.” Yet, demonstrations frequently interfere with the flow of traffic, sometimes 

escalate into property damage, and often spark counter-demonstrations. Police are 

charged with protecting the constitutional right of peaceful assembly, but they also have 

the responsibility to protect people on both sides of the issue, as well as bystanders and 

property. This is one of those situations in which police are literally stuck in the middle 

and sometimes cannot be completely successful, no matter how hard they try.

Measuring traffic safety (crashes, fatalities, and injuries) is reasonably straightforward, 

but measuring the level of order or disorder is not. This is particularly true because there 
SUGGESTED

READING

Wilson, J.Q. 1968. Varieties 

of police behavior: The 

management of law and 

order in eight communities.

Cambridge, MA: Harvard 

University Press.

Evidence-Based Policing in 45 Small Bytes 19

is no clear-cut standard for the “right” level of orderliness in a community — it can vary 

by neighborhood, by individual person, and over time. Conditions like loud music, public 

drinking, and kids on the corner constitute disorder in the minds of some people but not 

others. Although criminal laws that prohibit disturbing the peace and disorderly conduct 

are in effect everywhere, using discretion to negotiate the gray area between orderly and 

disorderly has always been a core function of policing.

Because safety and orderliness have both objective and subjective components, a police 

agency is likely to need multiple measures to track how it is doing. Later sections offer 

some suggestions.

Protecting Democracy

“The police have an important, but intermittent and rarely noticed impact on a different kind of public 

space — the public space in which politics are conducted. Police responsibility in this domain shows 

up in the vestigial requirement that the police guard polling places on election days to ensure that 

voters can cast their votes without intimidation, and prevent partisan violence from breaking out. It is 

often a bit more visible when the police do or do not grant permits for parades and demonstrations, 

and then police the mass gatherings that occur. It is also apparent when riots occur, and the police 

are called in both to restore order, and explain the causes of the disorder. The political role of the 

police is very important when the police deal with extortion or terrorism justified by some political 

ambitions. A democracy depends on individuals being able to settle their deeply held political 

disagreements peaceably, and it is among the most important challenges facing police to play 

an important role in keeping public deliberative spaces open and safe, as well as keeping public 

physical and recreational spaces safe.”

Source: Moore, M.H., and A. Braga. 2003. The “bottom line” of policing: What citizens should value (and measure!) in police 

performance. Washington, DC: Police Executive Research Forum, 47. http://www.policeforum.org/assets/docs/Free_Online_

Documents/Police_Evaluation/the%20bottom%20line%20of%20policing%202003.pdf. 
20 National Institute of Justice | NIJ.ojp.gov

BYTE 9

Reassuring the Public

P erception isn’t reality, but it does have consequences. Excessive fear of crime 

can cause people to stay indoors, put bars on their windows, move to a different 

neighborhood, or relocate their businesses to another city or town. Similarly, if 

people believe that police can’t be trusted, they don’t report crimes, step forward as 

witnesses, or participate in community-based problem-solving.

Because perceptions of crime and of police performance affect people’s quality of life 

and their interactions with law enforcement, they are an important dimension of the 

policing bottom line. A police agency’s effectiveness is highest when the public’s fear of 

crime is commensurate with actual risks, and when the public has trust and confidence 

in their police.

The traditional approach to reducing fear of crime was to work on reducing crime itself. 

Likewise, improving police professionalism was the approach taken to improve the 

public’s opinion of the police. However, it has often been the case that fear of crime 

goes up even as the crime rate goes down, and that the very people least at risk of 

being victimized are the most fearful. It is also common for improvements in police 

performance to go unrecognized by the public, and for an agency’s constituents to be 

influenced by policing incidents that occur hundreds or even thousands of miles away. 

Consequently, it makes sense for police to intentionally engage in reassuring the public 

rather than assuming that people will be well-informed on their own. Today, in the age of 

social media, this has become even more important.

There are two key elements of reassurance policing, both of which require good data. 

The first is that reassurance must be based on accurate information in order to have 

credibility. If crime is largely unreported, for example, or if reported crime information 

isn’t up to date, then the public might be given a false sense of security, or people might 

realize that the police aren’t actually on top of the situation. For example, if the police 

were to rely on their own perceptions in assuring the community that there was no racial 

disparity in vehicle stops, only to be contradicted by data, credibility and trust would 

be lost. 

The other element of reassurance policing is that, like most policing practices, it should 

be targeted. Consider fear of crime. Fear might be out of proportion to risks in some 

neighborhoods but not others, some demographic groups (such as older adults) might 

be more affected by fear of crime, and the particular causes of fear might vary between 
SUGGESTED

READING

Skogan, W.G., and M.G. 

Maxfield. 1981. Coping 

with crime: Individual and 

neighborhood reactions. Sage 

Library of Social Research, 

Vol. 124. Beverly Hills, CA: 

Sage Publications. http://www.

skogan.org/files/Coping_With_

Crime.pdf.

Evidence-Based Policing in 45 Small Bytes 21

groups, such as women’s fear of sexual assault. By the same logic, people’s perceptions 

of whether police behave properly might vary geographically and demographically. Thus, 

intentional police efforts to reassure the public should be tailored and calibrated to be as 

effective as possible and to avoid wasting energy where it isn’t needed.

Sometimes, it is possible to observe the consequences of public perceptions, such as 

families not using a neighborhood park or protesters appearing at a city council meeting. 

More often, surveys and interviews are used to gauge fear of crime and perceptions of 

police, providing data that can then be used to target their reassurance efforts.

Fear Matters

“Enhancing personal security, including the subjective experience of how safe people feel against the 

threat of criminal attack, is surely one of the most important goals of a police department. Indeed, 

one can reasonably argue that producing a widespread sense of security against criminal attack is 

the true outcome of policing — the result that comes from arresting offenders and reducing crime, 

and that constitutes the ultimate purpose of the police. To be rid of the fear of a criminal attack is to 

live much more happily than to live with an ever-present or intermittent fear.”

Source: Moore, M.H., and A. Braga. 2003. The “bottom line” of policing: What citizens should value (and measure!) in police 

performance. Washington, DC: Police Executive Research Forum, 44. http://www.policeforum.org/assets/docs/Free_Online_

Documents/Police_Evaluation/the%20bottom%20line%20of%20policing%202003.pdf. 
22 National Institute of Justice | NIJ.ojp.gov

BYTE 10

Providing Quality 

Services

P olice get contacted for all kinds of reasons — crimes, disturbances, traffic 

accidents, lost children, suspicious activity, individuals in crisis, alarms, speeders, 

keys locked in cars and, yes, cats in trees. Formal assistance may also be 

requested to provide security at sporting events, traffic control for parades, street 

closures for block parties, and background checks on child care workers. In addition, 

police often respond to fire and ambulance calls, sometimes taking immediate life-saving 

measures until other first responders arrive. The range of activities that police engage in 

is extremely broad.

It is accurate to say that policing is a service, and that police provide a wide array of 

services. By the same token, it would be deceiving to say that policing is just a service. 

Uniquely, police have the authority to do something about crimes, disturbances, 

suspicious people, and speeders. Police lead parades mainly because they can clear the 

way, not because they have nice cars. In other words, saying that policing is a service 

doesn’t diminish the fact that police have the license and capacity to make people 

behave, or else.

Some of the services that police provide have little to do with their official authority and 

could probably be delivered more effectively by others. But the reality is that the police 

make house calls and are open for business 24/7 year-round, neither of which is true of 

most other service providers. Also, many social service agencies simply don’t have the 

staff or budget to assist all the vulnerable people who need their help. Consequently, the 

police end up providing all kinds of services as best they can. Ideally, after completing an 

initial assessment, police make referrals to the appropriate public or private agency, but 

referral only works if that agency has the capacity to provide the needed services. Too 

often, the responsibility to try to help the person or resolve the situation falls back on the 

police.

Response time was the traditional indicator of good police service and is still important 

today, but it has two major limitations: (1) It measures how quickly police respond when 

someone calls but, by itself, does not reveal the quality of service delivered once police 
SUGGESTED

READING

McEwen, J.T., E.F. Connors, and 

M.I. Cohen. 1986. Evaluation of 

the differential police response 

field test. Washington, DC: 

U.S. Department of Justice, 

National Institute of Justice. 

NCJ 101267. https://

www.ncjrs.gov/pdffiles1/

Digitization/101267NCJRS.pdf. 

Evidence-Based Policing in 45 Small Bytes 23

arrive. (2) Studies have shown that an immediate response is not always productive 

or necessary — quick responses to cold crimes rarely produce arrests, and victim 

satisfaction is not primarily determined by how quickly the police show up.7 Modern 

agencies generally aim for short response times to high-priority calls while offering 

alternatives in other situations, such as telephone reporting, online reporting, and delayed 

response. Research has shown that these alternative responses can be satisfying to 

victims and complainants if they are explained and delivered professionally.

The other principal indicator of good police service is the customer satisfaction survey. 

Although “customer” is not really the right label for people who receive police services, 

the logic is the same — following up with people who have had police contact to find 

out if, according to the people, the police were polite, listened to them, gave good 

information, and provided satisfactory service. Naturally, not everyone gets what they 

want from the police, but systematically measuring customer feedback is a logical 

method for gauging the quality of services delivered and an important way to identify 

trends, issues, and problems deserving of attention from the agency’s managers.

Customer Satisfaction

“The police and those who oversee them should be interested in ‘customer satisfaction’ for at least 

two different reasons. First, producing customer satisfaction in those who interact with the police is 

valuable in and of itself. It is one of the goals toward which the police ought to be working. Second, 

to the extent that the police are responsive to the concerns of their clients and customers, and give 

them what they want, the police might well be rewarded with the loyalty and affection of the public. 

That loyalty and affection may help the police acquire additional resources. It might also ward off a 

tendency to rely increasingly on private rather than public security. Even more important, the public 

support and trust earned through quality services may help the police succeed in controlling crime. 

For all these reasons, in measuring police performance, it would be important to discover something 

about the experience of those who interact with the police.”

Source: Moore, M.H., and A. Braga. 2003. The “bottom line” of policing: What citizens should value (and measure!) in police 

performance. Washington, DC: Police Executive Research Forum, 68-69. http://www.policeforum.org/assets/docs/Free_Online_

Documents/Police_Evaluation/the%20bottom%20line%20of%20policing%202003.pdf. 

7

 Spelman, W., and D.K. Brown. 1984. Calling the police: Citizen reporting of serious crime. Washington, 

DC: U.S. Department of Justice, National Institute of Justice. NCJ 82276. https://www.ncjrs.gov/pdffiles1/

Digitization/82276NCJRS.pdf. 
24 National Institute of Justice | NIJ.ojp.gov

BYTE 11

Using Force and 

Authority Fairly 

and Effectively

T

echnically, using authority and using force are means, not ends, and as such might 

not seem like valid components of the policing bottom line. Nevertheless, they 

are included because they represent the core of the police role and because they 

dramatically affect citizens, both individually and collectively. In a free society, people 

relinquish some of their liberty and delegate power to police, in return for safety and 

order. Part of the bargain is that police agree to use that power sparingly and in ways that 

are lawful, equitable, and fair.

Examples of police exercising their authority include vehicle stops, person stops, frisks, 

searches, citations, and arrests. Police may also have authority to require people to 

evacuate a building, to disperse a disorderly crowd, or to take other actions in public 

safety emergencies. When individuals resist police exercising their authority, or when 

individuals threaten the police or others, then police may use reasonable force to 

overcome the resistance or threat. All of these situations surrounding police use of 

authority and force are heavily regulated by law as well as police policy, yet often a 

substantial degree of discretion remains.

Today, much of the public discussion about police centers on transparency, 

accountability, and legitimacy in relation to police use of force and authority. The reality, 

of course, is that society has police specifically because it needs an institution capable 

of regulating citizen behavior, by force if necessary — and yet, when police carry out this 

mandate, it is often controversial. Police leaders are expected to pursue using force and 

authority fairly and effectively as one of their organization’s highest priorities.

Police executives and the public need data on this aspect of the police function in order 

to judge how well the police agency is meeting the mandate of using force and authority 

fairly and effectively. The number and circumstances of police shootings are obviously of 

high interest, but metrics such as the percentage of arrests involving use of force beyond 

handcuffing, the number and percentage of vehicle pursuits ending in crashes or injuries, 

and the percentage of searches yielding evidence or contraband are equally important 

indicators of sound tactics and decision-making.
SUGGESTED

READING

Baumgartner, F.R., D.A. Epp, 

and K. Shoub. 2018. Suspect 

citizens: What 20 million traffic 

stops tell us about policing 

and race. Cambridge, UK: 

Cambridge University Press.

Tillyer, R., and R.S. Engel. 

2012. “Racial differences in 

speeding patterns: Exploring 

the differential offending 

hypothesis.” Journal of 

Criminal Justice 40 no. 4 

(July-August): 285-295. 

https://www.sciencedirect.

com/science/article/pii/

S0047235212000554?via

%3Dihub.

Evidence-Based Policing in 45 Small Bytes 25

An important and elusive element of using force and authority fairly pertains to race and 

ethnicity. It is routine and expected that data on arrests, stops, searches, and use of 

force will be examined for disproportionate impact on people of color, ethnic minorities, 

and women. A serious dilemma is that disproportionate impact is often found, but the 

data rarely provide much insight into reasons for the disparity. Consequently, advocates 

and police sometimes debate whether there is even a problem, never mind who is to 

blame and how to resolve it. More positively, though, the data can sometimes spark the 

kinds of creative and courageous conversations that communities need to have in order 

to make progress on race, police-community relations, and fair and effective use of force 

and authority.

Use and Abuse of Force and Authority

“The important measures indicating the overall level of force and authority used by the police must 

begin with individual instances of abuses of police force and authority. Abuse in an individual case 

means both that too much force and authority was used, and that it was unjustly used against that 

individual. If it turns out that excessive force occurs more often to people in a certain group, that 

group (as well as the individuals) might have reason to be concerned. Thus, a community would want 

to keep track of citizen complaints against the police.”

Source: Moore, M.H., and A. Braga. 2003. The “bottom line” of policing: What citizens should value (and measure!) in police 

performance. Washington, DC: Police Executive Research Forum, 55-56. http://www.policeforum.org/assets/docs/Free_Online_

Documents/Police_Evaluation/the%20bottom%20line%20of%20policing%202003.pdf. 
26 National Institute of Justice | NIJ.ojp.gov

BYTE 12

Using Financial 

Resources Fairly, 

Efficiently, and 

Effectively

H ardly anything is more despised in America than government waste, and we 

taxpayers part with our dollars very reluctantly. Because police are funded by the 

public’s money, it follows that the police are expected to use it wisely. This is so 

important that it is included as one of the seven bottom lines of policing, even though it 

is not really an outcome in the same way that reducing crime or reassuring citizens are 

outcomes. Certainly, one justification for including it is that financial mismanagement can 

easily cost police chiefs and sheriffs their jobs.

Fairness in resource allocation is a tricky criterion. Which deserves more police time and 

attention — a big-box retail store that suffers five thefts a week, or a small Main Street 

shop that gets hit twice a month? Should the police department focus more investigative 

effort on human trafficking, domestic violence, online child predators, or street gangs? 

Should every neighborhood get the same level of patrol, or should patrols be distributed 

according to need (crime and calls for service)? Every police agency has limited 

resources and therefore has to balance competing issues and demands like these, none 

of which are straightforward. Fairness is ultimately a subjective standard, open to debate 

and criticism.

Efficient use of resources is more straightforward. Contracts should be put out for bid to 

ensure that equipment and services are obtained at the best possible cost. Patrol officers 

should be allocated to shifts according to workload. Training courses should only be 

as long as needed to impart requisite knowledge and skills. Agencies should have the 

number of layers of organization necessary for command and control, and no more. The 

main focus of efficiency is avoiding wasteful spending so that the best possible policing 

outcomes are achieved at the lowest possible cost.

Effective use of resources pertains more to using the practices that work best, and not 

using practices that don’t work as well. This dovetails directly with evidence-based 

policing, the purpose of which is to make policing more effective. For example, following 

a practice like responding immediately to every reported crime is not an effective use of 
SUGGESTED

READING

Gascón, G., and T. Foglesong. 

2010. “Making policing more 

affordable: Managing costs and 

measuring value in policing.” 

New Perspectives in Policing

(December). Washington, DC: 

U.S. Department of Justice, 

National Institute of Justice. NCJ 

231096. https://www.ncjrs.gov/

pdffiles1/nij/231096.pdf. 

Evidence-Based Policing in 45 Small Bytes 27

resources; studies have shown that it produces neither more arrests nor more satisfied 

victims. But effectiveness depends on more than just adhering to principles about 

what works. It also depends on data; targeting works only if efforts are focused on 

problems that actually exist, and are focused when and where the problems happen. And 

effectiveness depends on analysis that uncovers the mechanisms and conditions that 

fuel the problem, giving the police guidance in choosing responses that really fit what’s 

going on.

Police departments have traditionally thought of this dimension of performance — using 

financial resources — as something technical and mechanical, handled by accountants 

and bookkeepers. However, much more is at stake. A jurisdiction gives its police 

agency an amount of money to work with each year, expecting that it will be used fairly, 

efficiently, and effectively. Accomplishing that high standard requires not only careful 

tracking and resource allocation but also (1) utilizing only those programs and practices 

that accomplish the best possible outcomes and (2) convincing people and groups with 

competing interests that the police are being as fair as they possibly can in how they use 

their resources.

Efficiency and Innovation

“The police should be engaged in a continuing search for better, lower cost ways to achieve their 

results. Like other modern, producing organizations, they have to learn how to put a premium on 

innovation. They have to examine how they do their work in all phases of their operations — how 

they staff and schedule dispatch operators, how they recruit and train officers, how they respond 

to a proliferating number of burglar alarms, how they handle domestic violence complaints, and 

what can best be done to close down street-level drug markets, to describe just a few of the literally 

thousands of ‘business processes’ that exist in a modern police department. They have to find out 

how their current procedures are working, and imagine and test alternative ways of producing the 

same results. When they find a superior method for performing a particular task, they have to deploy 

that new method quickly and widely to take full advantage of the opportunity they have created for 

themselves.”

Source: Moore, M.H., and A. Braga. 2003. The “bottom line” of policing: What citizens should value (and measure!) in police 

performance. Washington, DC: Police Executive Research Forum, 65. http://www.policeforum.org/assets/docs/Free_Online_

Documents/Police_Evaluation/the%20bottom%20line%20of%20policing%202003.pdf. 
28 National Institute of Justice | NIJ.ojp.gov

BYTE 13

Police Legitimacy

T

he significance of the seven dimensions of the policing bottom line, discussed in 

the preceding sections and represented in the middle column of figure 1, cannot 

be overstated. The public and their elected leaders expect the police to achieve all 

seven of these outcomes, or at least do everything possible to achieve them. Naturally, 

resources are limited, so priorities have to be established. Also, conditions and public 

concerns change over time, so priorities may shift. In the end, however, all seven 

dimensions really matter, which helps explain why policing and police administration are 

so challenging.

When people are satisfied that the police are doing everything within reason to achieve 

the entire set of outcomes — the whole bottom line — then they accept the legitimacy of 

the police and are most likely to cooperate with, assist, and support the police. In a free 

and democratic society, it is essential for the police to demonstrate that they are worthy 

of this kind of trust and confidence. That isn’t expected in a dictatorship, but in a society 

in which people self-govern and choose to delegate certain authority to the police, that 

authority comes with the responsibility to use it wisely and effectively.

Figure 1. Police performance, policing bottom lines, and police legitimacy

Police

Performance — 

Activities and 

Outputs

Reduce Serious Crime

Hold Offenders to Account

Maintain Safety and Order

Reassure the Public

Provide Quality Services

Use Force and Authority

Fairly and Effectively

Use Financial Resources

Fairly and Efficiently

Police 

Legitimacy

In recent years, studies have pointed to the significant impact of procedural justice 

on police legitimacy.8

 These studies have demonstrated that how police treat people 

and whether the public believes that police act fairly in their encounters with people 

8

 Mazerolle, L., S. Bennett, J. Davis, E. Sargeant, and M. Manning. 2013. “Legitimacy in policing.” Oslo: Campbell 

Collaboration. https://www.campbellcollaboration.org/library/legitimacy-in-policing-a-systematic-review.html. 
SUGGESTED

READING

Worden, R.E., and S.J. McLean. 

2017. Mirage of police reform: 

Procedural justice and police 

legitimacy. Berkeley, CA: 

University of California Press.

Evidence-Based Policing in 45 Small Bytes 29

affect how much the public trusts the police. In terms of the policing bottom line, this 

perspective mainly highlights the importance of using force and authority fairly and 

effectively.

The bottom-line framework is a good reminder, however, that police legitimacy depends 

on a range of outcomes, not just one. In some cities, for example, the public’s confidence 

in police is strained because of high levels of violent crime and disorder, along with 

the belief that the police don’t have the willingness or capacity to tackle the situation 

effectively. In other cities, police legitimacy is threatened not so much by the level of 

serious crime but because so few murders and shootings are solved. And, in some 

communities that don’t have serious crime problems, because police reassurance 

efforts have not been implemented or were not successful, residents feel fearful and 

unprotected even though they may have no reason to be. 

The best approach to establishing and maintaining police legitimacy is to recognize 

that procedural justice is important, but it isn’t the only factor. The challenge is to keep 

the bottom-line framework in mind. Each of its seven dimensions represents policing 

outcomes that matter to the public and that have the potential to strengthen or weaken 

police legitimacy.

Police Legitimacy and Police Performance

“In order to build trust and confidence — perceived legitimacy with the public — police must 

develop more complete performance metrics to measure and manage 21st Century policing. They 

must use data analytics to measure and manage organizational and individual member performance. 

They must hold themselves and their members accountable for the performance outcomes of their 

work, to include the impact of their actions on public perceptions of safety, justice and satisfaction 

with police service. Perhaps most important, elected officials must understand and embrace their 

responsibility to ensure their constituents receive the quality of police services they deserve.”

Source: McLay, C.S. 2016. “Building police legitimacy through measuring and managing police performance.” Blog. National 

Police Foundation. https://www.policefoundation.org/building-police-legitimacy-through-measuring-and-managingperformance. 

Evidence-Based Policing in 45 Small Bytes 31

SECTION 3:

Measuring External 

Conditions

T

he key aspects of the police mission are mainly focused outward — that is, not 

within the police organization but toward the community. Reducing crime, solving 

crimes, and reassuring the public are all examples of this outward-facing mission. 

A crucial prerequisite to achieving these outcomes is having detailed information about 

crime, disorder, and related matters. Obviously, the more accurate and timely that 

information is, the more helpful it is for identifying patterns and problems, diagnosing 

them, and choosing the best responses.

It is useful to think of this information in terms of situational awareness. In policing, this 

term is most often used in relation to tactical operations and officer safety, but it has 

broader applicability. To the extent that police officers, supervisors, and commanders are 

knowledgeable about crime, offenders, hot spots, public concerns, and similar conditions 

in the community, they are better able to respond with effective tactics, strategies, and 

programs. 

This expanded conception of situational awareness might not be valued in a police 

agency that only expects officers to handle calls and investigate crimes reported to them. 

But that kind of limited, reactive policing is not very effective, according to studies. Any 

agency seeking to be proactive, strategic, community-oriented, problem-oriented, and/

or intelligence-led needs to be guided by in-depth information about relevant community 

conditions.9 Otherwise, it’s operating in the dark.

Information, or data, is essential for evidence-based policing. One shouldn’t choose 

a particular crime-reduction initiative before first knowing as much as possible about 

the nature of the current crime problem. In other words, identification and diagnosis 

should occur before choosing a treatment, and that requires information. Furthermore, 

accurate data are needed in order to figure out whether target crimes were reduced after 

an initiative was implemented. And if a careful and rigorous evaluation is possible, data 

are needed to determine whether it is valid to claim that the initiative actually caused a 

crime reduction, or whether the decrease may have occurred due to some other factor or 

9

 Even small agencies need this kind of situational awareness. They need to be fully aware of what is going on in their 

communities. The difference, compared to large agencies, is that small agencies may not need formal or elaborate data 

collection efforts to be well-informed. Everyday observations, conversations, and routine recordkeeping may produce 

all the information that a small agency needs. 
SUGGESTED

READING

Ratcliffe, J. 2018. Reducing 

crime: A companion for police 

leaders. New York: Routledge.

32 National Institute of Justice | NIJ.ojp.gov

to normal fluctuation in crime rates. These actions — identifying the problem, analyzing 

it, diagnosing it, searching for its causes, choosing the right responses, and measuring 

effects — are all elements of an evidence-based approach to policing, and they all depend 

on accurate, reliable information.

Here in Section 3, this guidebook identifies and explains the key external conditions that 

any police agency should monitor and measure.

Diagnosing Problems Is Crucial

“The first reason for evidence-based policing relates to the need to understand the problems the 

police are attempting to address. If a problem is misconstrued, then finding an evidence-based 

solution to it will be difficult. The clinical counterpart in medicine is diagnosis. The physician needs to 

recognize the nature of the condition to determine which treatment fits it, and that can be tricky ... . 

The initial identification and analysis of the problem is crucial. Errors at these stages lead to errors in 

response decisions. Failures in the outcome of interventions reflect errors in analysis.”

Source: Tilley, N., and G. Laycock. 2017. “The why, what, when and how of evidence-based policing.” In J. Knutsson and L. 

Tompson, eds., Advances in evidence-based policing. London: Routledge, 10-11.
Evidence-Based Policing in 45 Small Bytes 33

BYTE 14

Crime and Disorder

Without a doubt, crime and disorder are among the most important conditions 

that police agencies need to monitor and measure. The reasons are obvious, but 

a few can be mentioned anyway:

1. So the agency knows whether these key, bottom-line outcomes are getting better or 

worse.

2. So the agency knows which particular crime and disorder problems are most serious 

and therefore deserve the most attention.

3. So the agency has data to analyze when, where, how, and why the crime and disorder 

problems are occurring, and in order to allocate resources properly and choose the 

best responses.

Collecting crime data is a well-established practice among police agencies. For 

monitoring purposes, many agencies systematically examine weekly, monthly, and yearto-date crime numbers, often with comparisons to prior years. The FBI’s Uniform Crime 

Reporting (UCR) categories are typically used, especially the eight Part I crimes (murder, 

rape, robbery, aggravated assault, burglary, auto theft, theft, and arson). 

It is important to avoid being limited to the major UCR categories. The example of 

shootings is most compelling. Just a few years ago, many cities were experiencing an 

increase in gun violence, but when asked how many shootings were occurring and how 

that compared to prior years, they couldn’t say. They could cite the number of murders 

and the number of aggravated assaults, but “shootings” wasn’t a crime category they 

had been using. This came to be seen as an important flaw in the data. The difference 

between a shooting and a murder is sometimes just an inch difference in where the bullet 

hits, or a slight delay in medical attention.

Although traditional crime counts are useful, long ago it was recognized that police 

agencies are best served when they compile incident-based crime data. As an 

illustration, it is one thing to know that a jurisdiction had 100 burglaries, but it is more 

helpful to know that it had 20 commercial burglaries and 80 residential ones. Even more 

useful is the knowledge that all the commercial burglaries happened at night, whereas 

most of the residential ones occurred during the day. And so forth. When crime data 

are incident-based, details like these — crucial for spotting patterns and choosing best 

responses — are easy to identify. But such details are lost, or at best elusive, if the crime 

data are only in aggregate form.
SUGGESTED

READING

Tilley, N. 2016. Analyzing and 

responding to repeat offending. 

Problem-Oriented Guides for 

Police. Problem-Solving Tools 

Series No. 11. Washington, DC: 

U.S. Department of Justice, 

Office of Community Oriented 

Policing Services. https://cops.

usdoj.gov/RIC/Publications/

cops-p259-pub.pdf. 

34 National Institute of Justice | NIJ.ojp.gov

Incident-based data about disorder are equally useful. An agency might want to track 

the number of noise complaints, for example, but in doing so, it would be important to 

distinguish among loud parties, construction noise, car horns, nightclub music, barking 

dogs, noisy bar patrons, fireworks, and any other frequently occurring irritants. Beyond 

noise, the types of disorder that should be measured and monitored by any particular 

agency probably vary. Some cities have squeegee guys (who try to clean your windshield 

for money) but most don’t; and some cities have daily demonstrations and protests, 

whereas others rarely have any. The principle would be to measure and monitor the most 

common and significant types of disorder in the jurisdiction, while remaining alert to any 

new forms of disorder that might crop up.

One challenge in monitoring overall crime from year to year is that aggregate totals 

can mask changes in crime severity. If an agency had 1,000 reported Part I crimes in 

consecutive years, for example, it might seem that nothing had changed, but if the 

second year had 50 fewer aggravated assaults and 50 more thefts, it was really a better 

year from the standpoint of crime seriousness. One way to handle this is by using a 

crime harm index that weights crime categories according to established criteria, such 

as the minimum recommended punishment in sentencing guidelines.10 Agencies should 

consider incorporating this kind of index in their ongoing monitoring and measurement of 

crime, not to replace traditional crime counts but to supplement them with an additional 

bottom-line indicator that is easy to understand and helpful for tracking changes 

over time.

Domestic Violence in Chula Vista

Chula Vista, California, is a city of 267,000 residents in the San Diego area. It has a progressive 

and data-savvy police department that was pleased to observe a 10% decrease in overall calls for 

service from 2007 to 2014. However, the agency’s second most common call type, domestic violence 

(DV), had not declined at all. In fact, noncrime DV calls had actually increased 18% during that 

same period. 

This is a good example of spotting a trend and problem by looking closely at the data. Careful 

examination also gave the police agency insight into the specific type of incident that was resisting 

their previous efforts. That led them to conduct more in-depth analysis and then search for 

alternative responses, which they subsequently implemented in 2015 and then evaluated over an 

18-month period. The result was a 24% decrease in DV crimes and calls after just one year.

Source: Adapted from Chula Vista Police Department. 2018. “Reducing domestic violence in Chula Vista, CA.” Presentation 

at 28th Annual Problem-Oriented Policing Conference. https://popcenter.asu.edu/sites/default/files/chula_vista_2018_pop_

conference_presentation.pdf. 

10 Sherman, L.W., P.W. Neyroud, and E. Neyroud. 2016. “The Cambridge crime harm index: Measuring total harm from 

crime based on sentencing guidelines.” Policing: A Journal of Policy and Practice 10 no. 3: 171-183. https://academic.

oup.com/policing/article/10/3/171/1753592. 
Evidence-Based Policing in 45 Small Bytes 35

BYTE 15

Traffic Crashes

As part of “maintaining safety and order,” traffic safety has been an important 

aspect of the police mission since at least the 1890s, when the first automobiles 

appeared on American roads. It addresses one of the biggest risks people face 

in modern life — in 2017, there were an estimated 40,100 motor vehicle-related deaths 

in the United States and almost 4.6 million injuries requiring medical attention.11 This 

compares to approximately 17,000 murders and 1.2 million other violent crimes in the 

same year.12 Although comparing the relative harm caused by crimes versus accidental 

crashes is not necessarily straightforward, the statistics certainly demonstrate that the 

human cost of traffic crashes is very high.

Decades ago, professional policing aimed at traffic safety began emphasizing the 

“three E’s” —engineering, education, and enforcement. Engineering seeks to make 

roadways, intersections, and vehicles safer. Education tries to influence behavior by 

improving drivers’ knowledge and skills. Enforcement targets driving offenses, to both 

catch individual bad drivers in the act and create a deterrent effect among the general 

driving public. 

Significantly, data are crucial for effective implementation of all three E’s. Basic crash 

data such as location and time of day are essential for targeting enforcement and may 

indicate the need for engineering responses such as more lighting, better signage, or 

additional traffic signals. Data on the causes of crashes, such as speeding, drinking, or 

distracted driving, can help guide all three approaches of enforcement, education, and 

engineering. 

These types of basic information are not sufficient for careful targeting, however. The 

causes of crashes at a certain intersection may differ between daylight hours and 

nighttime hours, for example. The type of crash may be important — rear-end versus 

head-on versus single-vehicle. The type of vehicle (e.g., trucks, cars, or motorcycles) is 

certainly relevant, along with the type of roadway (e.g., city street, rural road, highway). 

The availability and use of safety equipment, like seat belts and child car seats, is 

relevant. And then there are crashes involving pedestrians or bicycles. Just as with crime, 

a police agency needs incident-based data on traffic crashes so that it can accurately 

identify and diagnose problems as a precursor to selecting enforcement, education, and/

11 See https://www.nsc.org/road-safety/safety-topics/fatality-estimates. 

12 See https://ucr.fbi.gov/crime-in-the-u.s/2017/crime-in-the-u.s.-2017/topic-pages/tables/table-1. 
SUGGESTED

READING

Heinonen, J.A., and J.E. 

Eck. 2007. Pedestrian 

injuries and fatalities. Guide 

No. 51. Washington, DC: U.S. 

Department of Justice, Office 

of Community Oriented Policing 

Services. https://cops.usdoj.

gov/RIC/Publications/copsp135-pub.pdf. 

36 National Institute of Justice | NIJ.ojp.gov

or engineering responses that are targeted and tailored to the specific characteristics of 

the traffic crashes. Otherwise, the agency runs the risk of applying the wrong solutions to 

the wrong problems.

One condition that is related to traffic safety, but not always associated with traffic 

crashes, is speeding in residential neighborhoods. It is very common for police agencies 

to get numerous complaints about speeding in neighborhoods, and for residents to 

identify speeders as one of the top problems where they live. However, crash data 

often do not support the existence of a problem. Generally, the underlying story is that 

residents perceive traffic moving faster than it should, they regard it as dangerous, and 

they fear that crashes will happen as a result. Data can help sort this out; radar can be 

used to measure average speeds plus the number of cars going above a certain speed, 

helping both police and residents determine how serious the problem really is and what 

might be an appropriate response. 

Farm Labor Vehicles in California

A tragic vehicle accident in 1999 in California revealed a gap in traffic crash data. Thirteen farm 

workers died when the van they were being transported in collided with a tractor-trailer making a 

U-turn on a two-lane road. This incident brought to attention that “farm labor vehicle” was not a 

category in the state’s crash reporting system, making it difficult to determine how common such 

crashes were and how many fatalities and injuries had occurred over time. The highway patrol 

subsequently conducted a laborious search by hand of records going back a decade, which revealed 

a more serious problem than anyone had previously recognized. In response, the data system 

was updated, important new safety regulations for farm labor vehicles were legislatively imposed 

(including seat belts and forward-facing seats), and a rigorous education and inspection process was 

implemented. In subsequent years, fatalities associated with these kinds of vehicles were almost 

completely eliminated.

Source: Adapted from California Highway Patrol. 2002. SAFE: A safety and farm vehicle education program. Sacramento: 

California Highway Patrol. https://popcenter.asu.edu/sites/default/files/library/awards/goldstein/2002/02-07(W).pdf. 
Evidence-Based Policing in 45 Small Bytes 37

BYTE 16

Vulnerable People

V

ulnerable people are those who are at heightened risk of being harmed due to 

their age, physical or mental condition, or other factors. Police sometimes need to 

take extra efforts to protect vulnerable people from crime and other safety threats, 

since these individuals may not be as capable of self-protection as other members of 

the public.

Young people, the elderly, people in a mental health crisis, individuals with physical 

challenges, the homeless, substance abusers, immigrants, and members of minority 

racial and ethnic groups are among those who may be most at risk of being singled out 

by offenders or hate groups. People involved in abusive personal relationships (couples 

and children) are also particularly vulnerable. Another at-risk group is sex workers, 

especially street workers and young persons who are trafficked into these situations.

One form of police data on vulnerable persons is victim data. For example, police may 

keep track of individual domestic violence victims in order to make risk assessments, 

conduct follow-up visits, offer shelter or social service referrals, and be alerted in the 

event of repeat victimization. Similarly, police often track victims of elder abuse who might 

be at the mercy of unscrupulous caregivers or susceptible to repeat scams and fraud.

Police definitely need data on incidents involving vulnerable people in order to identify 

trends, patterns, and developing problems. Some of these incidents may be criminal, 

such as hate crimes or human trafficking, but others may involve less serious behavior 

such as harassment, intimidation, or just offensive conduct. Police agencies will want 

to be fully aware of all such incidents, whether they amount to crimes or not, in order to 

protect the vulnerable and prevent more serious behavior from occurring.

Homeless people, substance abusers, and persons with mental illness are among those 

who may sometimes need to be protected from themselves as well as others. Police 

data on people in these circumstances are likely to be limited by privacy considerations, 

among other factors. Emergency medical and ambulance services, public health 

agencies, and mental health treatment providers may be able to provide de-identified 

data to help police be more aware of patterns and trends, such as overdoses attributable 

to new synthetic drugs. 

Information about specific individuals and addresses can be very useful for police 

decision-making and officer safety. Officers handling domestic and family disputes 

should be provided with information about prior incidents in order to help them make 

accurate risk assessments, for example. Officers responding to an incident involving 
SUGGESTED

READING

Payne, B.K. 2013. Physical and 

emotional abuse of the elderly. 

Guide No. 71. Washington, DC: 

U.S. Department of Justice, 

Office of Community Oriented 

Policing Services. https://cops.

usdoj.gov/ric/Publications/

cops-p255-pub.pdf. 

38 National Institute of Justice | NIJ.ojp.gov

someone in a mental health crisis can make better sense of the situation, and have a 

better chance of de-escalating it, when they are aware of the subject’s condition and 

prior history. Otherwise, they may respond to bizarre or threatening behavior in a manner 

that has the unintended effect of escalating it, sometimes with tragic consequences.

The police need for data related to vulnerable people coincides with situational 

awareness. Officers, and the agency as a whole, should be well aware of the most 

vulnerable people in their community, and the specific threats they face, since those 

people need police protection even more than others.

Homeless Camps in Colorado Springs

In 2008, the police department in Colorado Springs, Colorado, faced a growing homeless situation. 

The city had 500 people living in tents on public land, and its previous approach of issuing citations 

and conducting camp clean-ups had come under criticism from community activists and civil 

liberties groups. In response, police began collecting more data about the problem. They surveyed 

100 homeless people and found that, on average, they had lived in the city 7.5 years and had been 

on the street 3.3 years. Reasons given for being homeless included “lost jobs, family, alcohol/drug 

addiction, injuries, physical and mental health issues, and legal issues.” Other local data indicated 

that 21% suffered from severe mental illness and 23% had chronic substance abuse. The police 

systematically got to know each homeless person and also identified locally available shelter, 

housing, food, employment, and treatment resources. They were able to link many of the homeless 

people with services and, in some cases, family members. Then, when a new warning-summonsarrest protocol was approved and implemented with substantial notice, they were able to eliminate 

all the existing public camps without making any arrests for illegal camping.

Source: Adapted from Colorado Springs Police Department. 2010. Homeless outreach team (HOT). Colorado Springs: Colorado 

Springs Police Department. https://popcenter.asu.edu/sites/default/files/library/awards/goldstein/2010/10-37(W).pdf. 
Evidence-Based Policing in 45 Small Bytes 39

BYTE 17

Known Offenders

A 1980s study in Washington, D.C., showed that police could identify prolific 

offenders, and when they targeted those specific individuals, they were able to 

make quality arrests that resulted in prosecutions and convictions.13 Since then, 

the use of offender-focused strategies has increasingly become an important adjunct 

to place-based strategies in the police repertoire for reducing serious crime. Today, in 

addition to targeting active offenders for arrest, police often use focused deterrence to try 

to convince selected offenders to change their criminal behaviors, and they track gang 

members with the aim of reducing violent clashes between groups.

Tracking and counting gang members has proven to be a particular challenge for many 

police agencies for several reasons: not all gangs are involved in serious crime; some 

people affiliate with gangs for protection or out of peer pressure but do not participate 

in criminal activity; many gang members join at a young age but leave as they get older; 

and gangs themselves are sometimes relatively fluid, thus membership is transient. 

These factors make it difficult for police to distinguish between gang members who are 

active criminals and those who are not. Agencies have sometimes come under criticism 

when their gang databases were found to list numerous individuals based on rather 

flimsy information, a situation that undercuts both operational effectiveness and an 

agency’s credibility with the public.

In larger police agencies, identifying and tracking known offenders is often the 

responsibility of specialist officers and intelligence analysts. This is particularly true for 

suspected terrorists, organized crime figures, drug traffickers, and gang members. On 

a more general level, though, officers should be aware of parolees, probationers, those 

on offender registries, wanted persons, and suspects in active cases. Part of situational 

awareness for patrol officers should be beat-specific information about these kinds of 

known offenders.

At the agency level, it is important to have data on the number of parolees, probationers, 

convicted sex offenders, and gang members living in the jurisdiction in order to assess 

risks, make plans, and allocate resources appropriately. Certainly, a significant increase in 

any of those categories should be cause to look more closely at the situation. While not 

a proactive example, some years ago, police in Madison, Wisconsin, noticed a significant 

increase in sex offenses. They eventually determined that the only sex offender treatment 

programs in the entire state were located in their city. Had they been fully aware of the 

influx of those offenders, they might have been able to respond to the situation more 

promptly and effectively.

13 See https://www.ncjrs.gov/pdffiles1/Digitization/98821NCJRS.pdf. 
SUGGESTED

READING

Schaefer, L., J.E. Eck, and 

F.T. Cullen. 2016. Monitoring 

offenders on conditional 

release. Response Guide 

No. 12. Washington, DC: U.S. 

Department of Justice, Office 

of Community Oriented Policing 

Services. https://cops.usdoj.

gov/RIC/Publications/copsp286-pub.pdf. 

40 National Institute of Justice | NIJ.ojp.gov

It goes without saying that police need to use information about offenders carefully 

and judiciously. This is especially true for people in two categories: (1) probationers, 

parolees, and ex-offenders — that is, those who have “paid their debt to society” and 

are now, hopefully, embarking on a better path — and (2) young offenders, including 

gang members, who may have made poor decisions but are likely to mature into better 

behavior. Police have always had to find the right balance between keeping a close 

watch on known offenders while not standing in the way of the human capacity to grow 

and change. Since digital data and modern technology have made it easier to track and 

monitor people, it has become even more important for police to be reasonable and 

thoughtful in how they carry out their responsibilities.

An important issue related to data and technology is the potential danger of reinforcing 

past bias and discrimination. If previous stops, arrests, and convictions were affected 

by prejudice, then current or predictive offender-focused targeting based on existing 

police records will likewise be flawed and will continue to reproduce unfair decisions and 

practices. This issue may complicate the development of the kinds of algorithms and 

other data-driven risk assessment tools that are becoming increasingly popular.14

Collecting Intelligence Data

“Targets create data. Offender groups are the targets. Citizens might see them. They might act in 

ways that provoke police stops and arrests. They might write graffiti or create social network pages. 

They may have bank accounts. They may be recorded by closed circuit television (CCTV). In each of 

these examples, a person or machine captures data describing group members.”

“Police gather data. Data from an informant, or on a digital recording device, or in a database 

needs to be collected to be analyzed. There are data capture processes that are obvious (e.g., police 

databases of offenders or CCTV footage from cameras near a crime site, confederates of members of 

an offender group) while other data capture processes require some creative thinking to recognize.”

Source: Eck, J.E., and R.V. Clarke. 2013. Intelligence analysis for problem solvers. Washington, DC: U.S. Department of Justice, 

Office of Community Oriented Policing Services, 14. https://cops.usdoj.gov/RIC/Publications/cops-p275-pub.pdf. 

14 Ferguson, A.G. 2017. The rise of big data policing: Surveillance, race, and the future of law enforcement. New York: 

New York University Press.
Evidence-Based Policing in 45 Small Bytes 41

BYTE 18

Fear of Crime

B ecause fear of crime is a feeling rather than a tangible event, it is sometimes 

overlooked as an important community condition worthy of police attention. 

However, fear has significant effects on individual lives and the health of 

communities. People often decide where to live, where to work, and where to shop 

based, in part, on whether they think particular areas are safe. A neighborhood or 

business district might flourish or fail based on the public’s perception of whether it is 

safe to frequent the area. 

It is important to recognize that fear of crime may be well-founded and protective. When 

it is exaggerated, though, its consequences are harmful. Studies show this is often the 

case — fear may increase while actual crime is decreasing, for example, and fear may be 

heightened by faraway events that don’t really represent any risk locally. For this reason, 

the police objective is best understood not simply as reducing fear of crime but, rather, 

as helping people and communities accurately understand and assess crime threats in 

their neighborhoods and region. Also, because fear is as much a feeling as a conscious, 

rational calculation, policing aims to reassure people, not just inform them, when their 

fears are out of proportion to actual levels of crime and disorder.

Data are essential for identifying and diagnosing fear-of-crime problems. With data, 

police agencies can tell if fear is exaggerated, whether it is increasing or decreasing, 

whether it is higher in some neighborhoods than others, and which demographic groups 

(such as older residents, women, or immigrants) have higher levels of fear. Data can also 

explore what people say they are afraid of — going out at night, going downtown, having 

someone break into their home, letting their children play outside, rowdy teenagers 

on the corner, and so on. Armed with this kind of information, police can target public 

education at specific audiences and focus on reassurance efforts addressing the specific 

conditions that most alarm people.

Many police agencies do not have access to fear-of-crime data, unfortunately, and very 

few have data at the neighborhood level. Agencies that do conduct periodic community 

surveys should, at a minimum, include items that measure fear and that identify the 

concerns that likely drive residents’ fears and worries related to crime. Such public 

surveys are more feasible now that online and text-based surveying have become 

common. Agencies can reach out to many more people without incurring substantial 

cost. And even though response rates are typically low, studies suggest that results are 

as reliable as those obtained from more traditional methods such as mail and telephone 

surveys.
SUGGESTED

READING

Cordner, G. 2010. Reducing 

fear of crime: Strategies for 

police. Washington, DC: U.S. 

Department of Justice, Office 

of Community Oriented Policing 

Services. https://cops.usdoj.

gov/RIC/Publications/copsp173-pub.pdf.

42 National Institute of Justice | NIJ.ojp.gov

In addition to formal surveys, police can explore people’s fears and concerns at 

neighborhood meetings, and they can monitor community sentiments on social media. 

Police can also conduct environmental visual audits with residents to identify specific 

locations or conditions — such as poor lighting or graffiti — that make people worry 

about their safety. These kinds of methods may provide the most in-depth and actionable 

information. Of course, it is then important for police to use the information, address the 

concerns, and follow up with residents to make sure they know that conditions have 

changed. Otherwise, people might be unaware that something has been done, which 

prevents them from being reassured and less fearful.

Crime and Fear of Crime in Seattle

Seattle is one city that surveys residents regularly, in support of its Micro Community Policing 

strategy. Fear of crime has remained fairly steady over the past three years, in the 45-50 range 

on a scale of 0-100. Results from the 2017 survey of 6,500 residents showed some disconnects 

between crime and fear of crime among the city’s 59 neighborhoods, though. In South Lake Union, 

for example, the crime rate was about twice the city average but fear of crime was second lowest 

among all neighborhoods. South Beacon Hill, with the city’s lowest crime rate, was 12th highest for 

fear of crime. Ten other neighborhoods had below-average crime but above-average fear. The survey 

director pointed to heavy media consumption as one contributor to exaggerated fear and noted, “Fear 

of crime is as important as actual crime if it decreases a person’s feeling of safety and impacts their 

quality of life.”

Source: Adapted from Helfgott, J.B., and W. Parkin. 2018. 2017 Seattle public safety survey results. Seattle: Seattle University, 

Department of Criminal Justice. https://www.seattle.gov/Documents/Departments/Police/Reports/2017_CITYWIDE_Seattle_

Public_Safety_Survey_Report.pdf; and Balk, G. 2018. “‘Mean world syndrome’: In some Seattle neighborhoods, fear of crime 

exceeds reality.” The Seattle Times (June 28). 
Evidence-Based Policing in 45 Small Bytes 43

BYTE 19

Citizen Complaints

Citizen complaints are an important indicator of the public’s assessment of police 

performance, because they provide data about encounters that citizens felt 

were unfair. Nevertheless, they shouldn’t be taken at face value or assumed to 

be broadly representative, nor should a lack of complaints be assumed to prove that 

everything is going great. Some citizens are too intimidated to file complaints. Others 

complain maliciously, either because they dislike the police or are trying to undercut 

charges filed against them. Also, many complaints are simply based on misperception, 

misinformation, or misunderstanding.

Historically, the resolution of many citizen complaints was a finding of “unsubstantiated” 

or “not sustained” because there was nothing to go on besides the citizen’s claim and 

the officer’s contradictory explanation. The usefulness of complaints data is limited 

when many or even most complaints fall into this unsubstantiated category. However, 

with increased availability of video from in-car cameras, body-worn cameras, and 

citizen cell phones, fewer complaints should end up unsubstantiated, with more findings 

of unfounded (did not occur as alleged), exonerated (occurred but the behavior was 

acceptable), or sustained (occurred and was not acceptable).

The Commission on Accreditation for Law Enforcement Agencies requires accredited 

agencies to compile “annual statistical summaries of complaints and internal affairs 

investigations, which are made available to the public and agency employees” (Standard 

26.2.5).15 Data on the nature of complaints — such as rudeness, failure to take action, 

harassment, or excessive use of force — can help the agency identify points of conflict 

with the community, and possibly patterns of officer behavior that should be addressed. 

Also, since most citizen complaints tend to be about rudeness and other relatively minor 

alleged misbehavior, publicizing the nature of complaints can help reassure the public 

that serious misconduct is rare.

Gathering and examining incident-level citizen complaint data is even more useful. It 

might be the case, for example, that rudeness complaints are more often lodged against 

younger officers or male officers compared to others. Certain kinds of complaints might 

arise more frequently from nighttime interactions with police, special unit encounters, 

or consent searches, or they might be more common in some neighborhoods than in 

others. Dispositions might follow a pattern, such as complaints from intoxicated drivers 

more often determined to be unfounded. As long as citizen complaint data are collected 

15 Commission on Accreditation for Law Enforcement Agencies, Inc. [CALEA]. Standards for law enforcement agencies: 

The standards manual of the CALEA law enforcement agency accreditation program. Sixth edition. 2018. Gainesville, 

VA: CALEA. 
SUGGESTED

READING

Walker, S.E., and C.A. Archbold. 

2019. The new world of police 

accountability. Third edition. 

Thousand Oaks, CA: Sage. 

44 National Institute of Justice | NIJ.ojp.gov

and maintained in an incident-level format, an agency can look for these kinds of 

patterns, which might help inform its own decision-making and provide a more complete 

picture for the public, contributing to transparency and accountability.

Citizen Complaints in Detroit

The Detroit Police Department maintains a citizen complaint database that includes the allegation; 

the finding; officer unit; officer sex and race; complainant age, sex, and race; and several other data 

fields for each case. Glancing at over 10,000 complaints received during 21⁄2 years shows a fairly 

steady volume over time, with the majority of complaints alleging violations of procedure or poor 

officer demeanor. Several precincts clearly account for more complaints than others. With data in this 

format, further analysis could look more specifically at complaint types by district, by officer sex and 

race, and so on, as well as the trend over time in regard to specific types of complaints.

Source: Adapted from City of Detroit. 2019. DPD citizen complaints. https://data.detroitmi.gov/datasets/dpd-citizen-complaints. 
Evidence-Based Policing in 45 Small Bytes 45

BYTE 20

Client Satisfaction

Whenever we purchase something online, stay at a hotel, or fly on an 

airplane, we get an email or text within a few days asking us for feedback. 

Sometimes, the companies only ask one question — an overall rating of the 

experience — although, if we click on that 1-10 response scale, it often takes us to a 

longer questionnaire. Those surveys can be a nuisance, but enough people reply to 

give the companies useful information about the quality of the service delivered, and 

clues to help identify any frequently occurring problems. The email or text is also a very 

inexpensive way for the company to show its customers that it cares about them.

In this byte, “client” refers to people who are the direct recipients of police services — 

crime victims, other people who call the police, drivers involved in traffic accidents, 

people stopped by police — as opposed to the public at large. Although overall public 

opinion toward police also matters, the interest here is in getting feedback from the 

people who actually have police contact. This feedback can be useful for identifying both 

the strengths and weaknesses of officers’ performance, providing insight that can help 

guide supervision, training, and policy development.

It should be emphasized that people who have contact with police are not really 

customers in the same way that companies like Walmart or Delta have customers, and 

simply making everyone satisfied is neither a goal of policing nor possible. Rather, the 

aim is to make people (clients) as satisfied as possible that they were treated fairly — 

even if they got a ticket, the police didn’t solve their crime, or the police didn’t take their 

side in a neighborhood dispute. This corresponds with the bottom line of “providing 

quality services” as well as the general notion that our government should treat each of 

us with all due respect.

Similar to what many companies do, the most systematic way to measure client 

satisfaction is with follow-up surveys. Today, police agencies typically obtain phone 

numbers and email addresses from people whom they encounter, making it feasible to 

send short questionnaires by text or email. In these police-contact surveys, individuals 

are often asked whether the officer explained what was happening and why, whether 

they were given the opportunity to express themselves, whether the officer listened to 

them, whether the officer was polite, and whether the officer provided information about 

what they should do next. These questions correspond with the concept of procedural 

justice, which holds that people’s assessments of police depend heavily on whether they 

feel they were treated fairly and with respect, even when they didn’t get the outcome 

they wanted.
SUGGESTED

READING

Rosenbaum, D.P., J. Escamilia, 

G. Enciso, T. Christoff, and 

S.M. Hartnett. 2016. Results 

from the police-community 

interaction (PCI) survey. 

Chicago: University of Illinois 

at Chicago. http://uicclj.

squarespace.com/policecitizen-interaction-pci. 

46 National Institute of Justice | NIJ.ojp.gov

It is important to collect this kind of feedback proactively and systematically. Traditionally, 

many police agencies just waited for any complaints from citizens about officer behavior 

or poor service, and used those as indicators of individual and overall performance. 

However, many people are not comfortable bringing their complaint about police 

behavior to the police, and conversely, some people are chronic complainers. Complaints 

are significant and have to be reviewed, but as a source of data about agency 

performance, and as a source of feedback for identifying training or policy needs, they 

should be supplemented with information that is more broadly representative. 

Another factor is that complaints are, by their nature, negative. Systematically following 

up with people to measure their satisfaction with how they were treated gets information 

from those who were pleased with their police encounter and from those who were 

not so satisfied. In fact, agencies that regularly solicit this kind of feedback are often 

pleasantly surprised by how positive the results are.

Service Quality in Seattle

The Seattle Police Department measures service quality using telephone surveys. Several times a 

year they contact a random sample of people who recently called 911 and got a police response. 

According to the September 2018 survey, 97% of people surveyed said the responding officer was 

professional and courteous, 92% said the officer listened to their concerns, and 92% said the officer 

answered their questions. A five-year comparison showed increasingly positive ratings on those and 

several other measures. The department indicates that “results of the surveys have been used to 

assess service delivery; examine differences between precincts; identify strategies and tactics to 

achieve specific service objectives; and provide feedback to officers, precinct captains, and watch 

lieutenants.”

Source: Adapted from Seattle Police Department. 2018. September 2018 service quality update: Feedback from the people we 

serve. https://www.seattle.gov/Documents/Departments/Police/Publications/CustomerSurveyReportSep2018Final.pdf. 
Evidence-Based Policing in 45 Small Bytes 47

BYTE 21

Public Trust

I

n any given year, 20-25% of people have some kind of contact with police, according 

to national studies.16 That means, of course, that most people don’t. Yet, people’s 

perceptions of police performance, effectiveness, and fairness still matter, even 

when they are based on past experiences or second-hand information. The public’s 

trust and confidence in police affects individuals’ willingness to step forward as 

witnesses, taxpayer support for police funding, and also the social climate within which 

police officers do their work. In the big picture, policing effectiveness depends on the 

vast majority of the public accepting that the police are a trustworthy and legitimate 

institution.

The public’s trust in police has gotten a lot of attention in the past few years, particularly 

in response to officer-involved shootings, police handling of mass demonstrations, and 

other highly publicized events. The 24-hour news cycle and the rapid expansion of social 

media have undoubtedly made everyone more aware of policing in action and have made 

many police feel like they are constantly being criticized and second-guessed. 

In this kind of environment, it is arguably even more important to regularly assess the 

public’s trust and confidence in the police, in order to know whether the loudest voices 

are representative of the entire community. Often, they are not. Nationally, confidence in 

police fell between 2013 and 2015 but, as of mid-2017, it had rebounded to the 25-year 

average.17 As of 2018, national public confidence in police was third highest out of 15 

institutions, behind only the military and small businesses.18

As reassuring as these national figures are, each police agency should conduct its own 

local assessment to establish situational awareness and to identify any specific problems 

that should be addressed. Many agencies conduct community surveys on their own 

or in conjunction with their parent governments. One key consideration is conducting 

such surveys in a manner that is likely to provide results that reflect the views of the 

whole community. Posting the survey on the agency’s website or distributing surveys at 

community meetings can provide useful information from the handful of people who fill 

them out, but those methods are unlikely to reach a representative sample of the whole 

population.

16 See https://www.bjs.gov/content/pub/pdf/cpp15.pdf. 

17 See https://news.gallup.com/poll/213869/confidence-police-back-historical-average.aspx. 

18 See https://news.gallup.com/poll/236243/military-small-business-police-stir-confidence.aspx. 
SUGGESTED

READING

Office of Community Oriented 

Policing Services. Community 

survey on public safety and law 

enforcement. 2014. Washington, 

DC: U.S. Department of Justice, 

Office of Community Oriented 

Policing Services. https://cops.

usdoj.gov/ric/Publications/copsw0743-pub.pdf. 

48 National Institute of Justice | NIJ.ojp.gov

When a well-conducted community survey produces representative data, a police 

agency can do more than just get an overall measurement of public trust. At the 

very least, it should also be able to determine whether trust is lower among some 

demographic groups, which is often the case, and to provide guidance for targeted 

efforts at relationship building. In addition, the agency may be able to discover whether 

any particular police practices are harming trust, whether people are well informed about 

the full range of the agency’s services, and where people get their information about their 

local police. Insight like this can help any agency fine-tune its community engagement 

and outreach activities. It goes without saying that trust has to be earned; data can help 

police figure out how best to earn it.

Community Survey in Prince William County, Virginia

The Prince William County, Virginia, government conducts a community survey every two years, 

including several questions related to its county police department. The 2016 survey reached over 

1,500 respondents by phone or online. Respondents were given six positive statements about police 

performance and asked to rate each statement from 0 (disagree) to 10 (strongly agree). For each of 

the six police-related items, more than 90% of respondents gave ratings of 5 or higher, indicating 

agreement or strong agreement. For the item “Police officers are courteous and helpful to all 

community members,” the average rating was 7.83 out of 10, up from 7.73 in 2014. For “The police 

department treats everyone fairly regardless of race, gender, ethnic or national origin,” the average 

rating was 7.69 out of 10, up from 7.52 in 2014. For “The police department’s overall performance 

meets community needs,” the average rating in 2016 increased to 7.84, up from 7.64 in 2014. 

Survey results can be broken out by region of the county, age, sex, race/ethnicity, and several other 

personal variables to check for patterns and look for subgroups whose opinions might not be quite as 

positive as those of the overall population.

Source: Adapted from ORC International. 2016. 2016 citizen survey. Woodbridge, VA: Prince William County Government. 

http://www.pwcgov.org/government/dept/budget/Documents/2016_Community_Survey_Report.pdf. 
Evidence-Based Policing in 45 Small Bytes 49

SECTION 4:

Measuring Internal 

Conditions

T

hus far in its development, evidence-based policing (EBP) has been mainly focused 

outward on what matters most — the bottom-line outcomes of policing. In order 

to achieve those outcomes, though, the inside of the police organization has to 

work well, too. In systems terms, a police agency has to acquire the right inputs and 

then process them into outputs that, hopefully, contribute to accomplishing the results 

that matter, such as reducing serious crime and reassuring the public. In human terms, a 

police agency needs good people and needs to treat them well, since it’s the people who 

do the work of policing.

Some years ago, the police chief in Madison, Wisconsin, learned the hard way that he 

needed to pay more attention to internal conditions in his agency.19 He was a progressive, 

community-oriented, and demanding chief, but he wasn’t getting as much commitment 

and buy-in from his officers or commanders as he needed. He eventually came to realize 

that he wasn’t behaving very sympathetically or respectfully toward the people in his 

police department — yet he was expecting them to become more sympathetic and 

respectful in the way they dealt with the public. Once he recognized what was happening, 

he paused his effort to implement community policing and adopted an “inside-out” 

strategy. He pledged to change his management style and address internal conditions 

within the agency first, before asking officers to change their behavior and relationships 

in the community. He kept his pledge, and an independent evaluation showed that the 

police department’s bottom-line outcomes improved significantly after this strategy was 

implemented.

The logic of an evidence-based approach to the inner workings of an agency is exactly 

the same as the overall logic of EBP. A police agency’s internal practices should be based 

on evidence about what works. Plus, an agency needs data and analysis to keep track 

of how things are going within the organization to identify any problems that need to be 

fixed. An agency needs to monitor officer safety, morale, recruitment, training, technology, 

and a plethora of other internal conditions that ultimately affect the extent to which it 

achieves, or doesn’t achieve, the bottom-line outcomes the public counts on.

19 Couper, D.C. 2011. Arrested development. Indianapolis, IN: Dog Ear Publishing.
SUGGESTED

READING

Wycoff, M.A., and W.G. 

Skogan. 1993. Community 

policing in Madison: Quality 

from the inside out: An 

evaluation of implementation 

and impact. Washington, 

DC: U.S. Department of 

Justice, National Institute of 

Justice. NCJ 144390. https://

www.ncjrs.gov/pdffiles1/

Digitization/144390NCJRS.pdf. 

50 National Institute of Justice | NIJ.ojp.gov

Here in Section 4, this guidebook addresses a few of the most important internal 

conditions that police managers and executives need to monitor. The section could be 

much longer, but in the interest of brevity it is kept short. The gist of this section is that 

internally focused police administration, just like externally focused police operations, 

should be as evidence-based as possible.

The Inside-Out Approach in Madison, Wisconsin

“I have to admit that when I first came to the department and began to encounter trouble within the 

ranks, my leadership style became more and more top-down, relying on force to get the job done. 

I felt threatened, and I fought back in the way I knew at the time — coercion. I now know coercive 

force might be the easiest way for leaders to operate when they encounter resistance. But it isn’t the 

most effective way in the long run.”

“Police departments today are complex organizations, and things don’t just happen because the chief 

orders it. Any effort at changing the police must take into account the power of the organization to 

drag its feet; to resist. That is why any effort to change police must begin inside a department and, 

ultimately, be able to answer this question from the rank and file: ‘What’s in it for us?’ If a changeoriented chief and his or her staff cannot effectively answer that question, what is proposed most 

likely will fail.”

Source: Couper, D.C. 2011. Arrested development. Indianapolis, IN: Dog Ear Publishing, 104, 106.
Evidence-Based Policing in 45 Small Bytes 51

BYTE 22

Officer Safety, Health, 

and Wellness

T

here aren’t any internal conditions more important than officer safety, health, and 

wellness. The police field has given substantial attention to officer safety since 

the 1970s, leading to much improved tactics, training, and equipment. The same 

level of attention to health and wellness has been harder to build and sustain, perhaps 

because it encroaches more on officers’ personal and private lives as opposed to onduty behavior. Nevertheless, awareness of the effects of fatigue, burnout, stress, and 

poor lifestyle choices on both the physical and mental health of police officers has been 

growing in recent years.

At the national level, data on officer fatalities are collected in three places: the FBI’s 

Law Enforcement Officers Killed and Assaulted (LEOKA) program, the National Law 

Enforcement Officers Memorial Foundation, and the Officer Down Memorial Page. 

These collections differ slightly in their criteria for counting line-of-duty deaths, but 

looking at all three provides a reliable annual count. The LEOKA program also gathers 

data on officers assaulted. However, as with all aspects of the Uniform Crime Reporting 

program, reporting is voluntary — making national figures of officers assaulted difficult 

to validate. Even harder to estimate nationally is the number of officers injured each year, 

since injuries can result from various causes, including assaults but also, for example, 

accidents. A study in one city determined that half of police officer injuries were caused 

by assaults, but half had other causes.20

Traffic crashes account for about 50% of police line-of-duty deaths each year as well as 

many injuries. Sadly, officers involved in fatal or injury crashes often were not wearing 

their seat belt/shoulder harness. One of the clearest evidence-based steps that can 

be taken to improve officer safety is to get officers to utilize standard occupant safety 

equipment and drive more defensively.21

Another alarming cause of officer fatalities is suicide. Data on the number of police 

suicides are particularly hard to collect and verify, but it is widely believed that more 

officers die from suicide than from any other single cause. Related concerns are 

depression, burnout, and stress resulting from frequent exposure to trauma, seeing 

people at their worst, and often being unable to make things much better for victims 

20 Brandl, S.G., and M.S. Stroshine. 2003. “Toward an understanding of the physical hazards of police work.” Police 

Quarterly 6 no. 2: 172-191. https://journals.sagepub.com/doi/abs/10.1177/1098611103006002003. 

21 See https://www.cdc.gov/niosh/topics/leo/toolkit.html. 
52 National Institute of Justice | NIJ.ojp.gov

and others. One potential consequence is post-traumatic stress disorder, which can be 

a debilitating and career-ending condition. Making matters worse, police officers are 

typically reluctant to seek help for mental health issues, fearing that their colleagues will 

lose trust in them, and their agency might find them unfit for duty.

A final set of issues includes fatigue, sleep, nutrition, exercise, and work-life balance. 

Studies have shown that shift work and night work often lead to inadequate sleep and 

fatigue. These conditions are sometimes compounded by mandatory court appearances, 

overtime shifts, extra-duty assignments, and part-time jobs. As a result, police officers 

may come to work tired, which can affect their on-the-job decision-making. In addition, 

many officers report poor eating habits, lack of regular exercise, and overconsumption 

of caffeine. This lifestyle, besides affecting their on-duty alertness and fitness, also puts 

officers at risk of developing medical conditions such as heart disease and high blood 

pressure.

A police agency should be monitoring the safety, health, and wellness of all its 

employees, but especially its officers. If data are routinely collected on assaults, injuries, 

sick leave, and hours worked, the agency can identify any organization-level trends or 

problems as well as any troubling patterns involving specific officers. Ideally, annual 

medical exams and physical fitness tests can also be used, although the details of 

medical exams may be subject to privacy considerations. It is important to emphasize 

to officers that the objective of these annual exams is officer health and well-being, not 

anything punitive. 

Officer fatigue is a challenging condition to measure and monitor, but it is widely 

understood to be a key factor in officer performance and safety.22 Experts suggest 

limiting the total number of hours worked in a day or on consecutive days, avoiding 

rotating shifts if possible, and even permitting short naps when necessary to avoid 

drowsy driving.

Officer mental health is another condition that agencies find nearly impossible to 

measure and monitor. Police agencies strongly encourage officers to take advantage 

of employee assistance (counseling) and peer support programs, but participation is 

normally voluntary and confidential. For data, sometimes the best that agencies can do is 

track the stressful incidents that officers encounter so that services or accommodations 

can be offered, especially when it looks like an officer has been exposed to an inordinate 

amount of trauma and sadness. Most agencies will take note of specific stress-inducing 

events, such as an officer-involved shooting or fellow-officer fatality. But more attention 

should also be given to accumulated stress from handling serious traffic accidents and 

witnessing child abuse, family violence, and similar incidents that inevitably take a toll on 

officers’ mental health.

22 Force Science Institute. 2019. “Study: Officer fatigue raises likelihood of citizen complaints.” Law Officer (February 1).
SUGGESTED

READING

Kuhns, J.B., E.R. Maguire, 

and N.R. Leach. 2015. 

Health, safety, and wellness 

program case studies in law 

enforcement. Washington, DC: 

U.S. Department of Justice, 

Office of Community Oriented 

Policing Services. https://cops.

usdoj.gov/RIC/Publications/

cops-p332-pub.pdf. 

Evidence-Based Policing in 45 Small Bytes 53

Heart Health Screening

“The Cedar Park (Texas) Police Department offers a voluntary heart health screening program as a 

free benefit to employees. Officers are well informed that in addition to being voluntary, the screening 

results are protected by HIPAA and thus cannot be shared with the department. Since the department 

has been running the screening program, it has seen more than half of the officers with identified risk 

factors proactively make changes to improve their health and reduce their risk.”

Source: Spence, D., ed. 2017. Improving law enforcement resilience: Lessons and recommendations. Washington, DC: U.S. 

Department of Justice, Office of Community Oriented Policing Services, 32. https://cops.usdoj.gov/RIC/Publications/copsp362-pub.pdf. 
54 National Institute of Justice | NIJ.ojp.gov

BYTE 23

Employee Attitudes, 

Knowledge, Skills, 

and Talents

E

mployees’ attitudes, beliefs, perceptions, and concerns can influence their behavior 

and performance, potentially affecting the organization’s success in achieving 

bottom-line outcomes. Although it is important to acknowledge that psychological 

factors like attitudes and beliefs do not always govern behavior (dissatisfied employees 

sometimes work just as hard as satisfied ones, for example), it is also naive to think that 

managers can afford to ignore what employees believe and feel. In policing, officers 

who have negative attitudes toward a minority group might treat members of that group 

differently, consciously or unconsciously. Officers who believe agency discipline isn’t 

fair might be less cooperative in internal investigations. Civilian employees who feel like 

second-class citizens in the police organization might be more likely to leave for other 

jobs. Potential impacts like these certainly matter.

Part of situational awareness for law enforcement managers and executives, then, is 

staying in touch with employee attitudes, beliefs, perceptions, and concerns in order 

to identify any conditions or trends that might be problematic. Some of this can be 

accomplished informally through first-line supervisors and “managing by walking 

around,” but especially in larger police agencies, focus groups and surveys might be 

needed to collect information more systematically.

Fortunately, agencies don’t need to start from scratch in this regard. Back in 2009, a 

project called the National Police Research Platform began developing and testing online 

employee surveys, eventually collecting data in over 100 police and sheriff agencies.23

This federally funded initiative is continuing under the direction of the National Police 

Foundation.24 Law enforcement agencies that participate can track their employees’ 

sentiments over time, with the added benefit of comparison to other similarly sized 

agencies around the country. This is very helpful — it is one thing to know that job 

satisfaction among your officers is, hypothetically, 3.7 on a 5-point scale, but it is much 

more valuable to know how that compares to a relevant national average or benchmark.

23 See http://uicclj.squarespace.com. 

24 See https://www.nationallawenforcementplatform.org. 
SUGGESTED

READING

Morin, R., K. Parker, R. Stepler, 

and A. Mercer. 2017. Behind 

the badge: Amid protests and 

calls for reform, how police 

view their jobs, key issues 

and recent fatal encounters 

between blacks and police. 

Pew Research Center. https://

www.pewsocialtrends.

org/wp-content/uploads/

sites/3/2017/01/Police-Report_

FINAL_web.pdf. 

Evidence-Based Policing in 45 Small Bytes 55

A related consideration within agencies is employees’ knowledge, skills, and talents. This 

is less about how employees feel and more about what they know and can do, which is 

directly related to their performance. Law enforcement agencies often keep a database of 

officers’ special skills — such as foreign language proficiency or accident reconstruction 

certification — in case those services are needed on short notice to handle a situation. 

More generally, though, it is important to have an up-to-date inventory of employee 

education, training, skills, and talents in order to identify any gaps and weaknesses that 

could interfere with overall performance and effectiveness. Such an inventory can also 

help with personnel planning by identifying gaps that will occur due to the anticipated 

retirement of employees who were depended upon for their particular skills and talents. 

Not every employee departure can be predicted, of course, but organizations should 

make an effort to have backup staff prepared for positions and duties that require special 

skills and talents.

Police Organizational Cultures Vary

There is a tendency to assume that the police occupational culture is so strong and universal that 

it leads all police to have the same attitudes and beliefs. If this were true (which it isn’t), it would 

be futile for any one agency to try to encourage a more positive outlook among its officers. In fact, 

officers vary individually. In addition, there are substantial differences between organizations, 

suggesting that what police managers and leaders do makes a difference in their organizational 

culture.

One study administered officer surveys in 89 agencies around the country. In response to the item 

“The disciplinary process in my agency is fair,” 87% of officers in one agency agreed versus only 

4% in another agency. Similarly, for the item “Most people respect the police,” 92% agreed in one 

agency, but only 23% in another. This shows how widely officer attitudes can vary; it points to how 

valuable it would be to know if the views of officers in a particular agency are far more negative than 

the norm.

Source: Adapted from Cordner, G. 2017. “Ideas & insights, part 1: Police culture in the 21st century.” Police Chief (February): 50-51. 
56 National Institute of Justice | NIJ.ojp.gov

BYTE 24

Discipline and 

Grievances

Within a law enforcement agency, disciplinary actions and grievances are 

two formal indicators of conflicting expectations, although they come from 

opposite directions. Disciplinary actions come from the top down, sanctioning 

employee behavior deemed to be unacceptable. Grievances come from the bottom 

up, when employees allege that they have been dealt with unfairly by the organization. 

Both types of actions can serve as flags or warnings that specific employees may 

need closer scrutiny, but these actions also generate data that may point to broader 

organizational issues.

It is important to recognize that neither discipline nor grievances are necessarily 

indicative of significant organizational problems, but it is wise to monitor them. In 

regard to discipline, a sharp increase in formal actions could signal a growing behavior/

performance problem among officers, or it could just be that certain behaviors are no 

longer being tolerated. Similarly, it could indicate a shift in sergeants’ behavior — either 

lax supervision failing to prevent officer misbehavior or stricter supervision resulting 

in more formal disciplinary actions being taken. The same is true for the nature of 

disciplinary infractions. An increase in discipline for rudeness, excessive force, sexual 

harassment, or any other specific violation might reflect an actual increase in misconduct, 

or it might simply reflect more enforcement. In other words, data on disciplinary actions 

in an agency don’t necessarily speak for themselves, but they certainly should be 

carefully monitored, since they might signal serious problems in the organization that 

need to be addressed.

The same line of reasoning applies to grievances. Many agencies report very few formal 

grievances, which ideally is a reflection of a positive and supportive organizational 

climate, but sometimes it is due to employees believing that it is useless to complain, 

or even that grievances will result in retaliation by management. Other agencies 

report numerous grievances being filed, which may signal a strained relationship with 

management, or may merely be an artifact of collective bargaining or a civil service 

system that tends to formalize processes that are handled elsewhere with a conversation 

and a handshake. In any of these scenarios, an increase in the number of grievances, 

or a pattern in the types of grievances being filed, might indicate a worrisome change 

in conditions within the organization, or just the election of a more confrontational union 

president, or some other factor. Again, the data on their own won’t necessarily reveal the 

full story, but they can signal a situation that should be looked into more closely.
SUGGESTED

READING

Stephens, D.W. 2011. 

“Police discipline: A case for 

change.” New Perspectives in 

Policing. Washington, DC: U.S. 

Department of Justice, National 

Institute of Justice. https://

www.ncjrs.gov/pdffiles1/

nij/234052.pdf. 

Evidence-Based Policing in 45 Small Bytes 57

The Commission on Accreditation for Law Enforcement Agencies 

(CALEA) Standard 22.4.3 — Grievances

“Annually, the agency conducts an analysis of its grievances, as well as supporting policies and 

practices, and it is reviewed by the chief executive officer.”

“Commentary 

The grievance procedure is a valuable method for management to discover agency problems and it 

is essential the chief executive officer is aware of information discovered through annual analyses. If 

through analysis the chief executive officer observes a trend in filed grievances, steps may be taken 

to minimize the causes of such grievances in the future.”

Source: Commission on Accreditation for Law Enforcement Agencies, Inc. [CALEA]. Standards for law enforcement agencies: The 

standards manual of the CALEA law enforcement agency accreditation program. Sixth edition. 2018. Gainesville, VA: CALEA. 
58 National Institute of Justice | NIJ.ojp.gov

BYTE 25

Applicants and 

New Hires

T

he quantity and quality of a law enforcement agency’s personnel have a major 

impact on its effectiveness. Recruitment and selection are the processes that 

organizations use to attract the attention of potential employees, get them to 

apply, and then decide which candidates actually get hired. Tracking and monitoring 

the recruitment and selection processes is very important for determining whether the 

agency is ending up with the kinds of people it needs to be successful, and if not, what 

the problems are that need to be corrected.

The emphasis on police recruiting in recent years has mainly been twofold: attracting a 

sufficient number of applicants to fill positions, and attracting a diverse pool of applicants 

that is representative of the community served. Many agencies have struggled on both 

counts, often blaming the strong economy (there are lots of other jobs for people to 

consider); the police hiring boom back in the 1990s (many sworn staff are now retiring, 

creating more than the usual number of vacant positions); and the diminished popularity 

of a police career (due to controversial police shootings, heightened media/political 

scrutiny, and strained police-community relations). Only time will tell whether these are 

permanent trends or simply reflections of a cycle that seems to produce a “recruiting 

crunch” every decade or so.

Regardless of national trends, each agency has its own challenges and positions to 

fill. Tracking data on those who apply for jobs can help an agency determine whether 

its recruiting efforts are reaching the right audiences and generating sufficient interest 

among potential applicants. To the extent possible, these data should indicate not only 

the total number of applicants but also important personal characteristics such as sex, 

age, race/ethnicity, education, and work/military experience, which can reveal whether 

targeted recruiting is needed to attract particular kinds of applicants. Studies have 

shown that small changes in recruitment messaging can substantially increase overall 

applications as well as those from targeted groups.25 

It is equally important to examine data from the selection process that determine which 

applicants end up getting hired. One common finding is that more applicants drop out 

when the process is lengthy, including some of the better applicants, since they are 

25 See https://www.bi.team/wp-content/uploads/2019/01/BIT-Police-report_MKV5-WEB.pdf. 
SUGGESTED

READING

The Behavioral Insights 

Team. 2019. Behavioral 

insights for building the police 

force of tomorrow. https://

www.bi.team/wp-content/

uploads/2019/01/BIT-Policereport_MKV5-WEB.pdf. 

Evidence-Based Policing in 45 Small Bytes 59

more likely to have other options. Another typical finding is that particular aspects of 

the testing process eliminate greater numbers of applicants, or have a disproportionate 

impact on certain categories of applicants, such as a high percentage of women failing 

the physical fitness test. In any of these kinds of situations — a long hiring process, or 

a test that eliminates a lot of applicants or has a disproportionate impact — an agency 

should take a careful look to make sure that its practices are necessary, legal, and 

evidence-based. The point to be made here is that law enforcement agencies need the 

data to know whether they have a situation that should be examined.

Recruitment Messaging

“In Chattanooga, Tennessee, we found that postcards asking ‘Are you ready to serve?’ were no better 

at soliciting applications than never sending a postcard at all. In contrast, postcards that asked ‘Are you 

up for the challenge?’ or ‘Are you looking for a long-term career?’ attracted three times more applicants 

than the no-postcard group and drove a fourfold increase in applications from people of color.”

“In South Bend, Indiana ... we tested postcards that referred to aspects of a police officer’s identity 

at home and at work to show that there are many sides to being a police officer. This approach was 

powerful, with recipients of this postcard being seven times more likely to complete an application 

than those who were not prompted.”

“In Tacoma, Washington, a[n] ... approach told people ‘You Belong Here,’ suggesting that there 

are many types of people that can find a home in policing. This proved to be an effective strategy, 

boosting applications fourfold compared to the status quo.”

Source: The Behavioral Insights Team. 2019. Behavioral insights for building the police force of tomorrow. https://www.

bi.team/wp-content/uploads/2019/01/BIT-Police-report_MKV5-WEB.pdf, 8-10.
60 National Institute of Justice | NIJ.ojp.gov

BYTE 26

Training

C ompared to other occupations, police rely heavily on training to make sure that 

employees, particularly sworn officers, have the knowledge and skills necessary 

to do their jobs. Doctors, nurses, lawyers, teachers, social workers, and others 

mainly acquire their professional knowledge and skills via higher education, but policing 

has traditionally relied more on separate institutions (police academies) to provide initial, 

ongoing, specialized, management, and leadership training. Law enforcement also 

utilizes field training, a form of coaching, to help new police academy graduates — as 

well as experienced staff who are newly promoted or reassigned — to properly apply 

what they have learned in the classroom. 

Because training is such an important element of policing, and a costly one, it makes 

sense that police agencies would want data for tracking and monitoring purposes. 

One important consideration is meeting state mandates along with requalification and 

recertification requirements. Besides mandated recruit training, most states require 

annual or biannual refresher training for sworn officers, and some also have specific 

training mandates for chiefs, dispatchers, 911 operators, new sergeants, and others. 

In addition, ongoing training may be necessary to retain certification in specific skill 

areas, such as first aid, or for specific pieces of equipment. States often require periodic 

firearms training and requalification as well, and even when they don’t, most agencies 

follow a regular protocol of their own, sometimes as often as quarterly.

Data that help an agency keep on track with training compliance are quite important — 

they can be useful for demonstrating professionalism and are essential when defending 

against lawsuits. Beyond that, however, data are needed to identify trends, issues, and 

problems with the training itself. Data on how well trainees have learned (or haven’t 

learned) key knowledge, how well they have mastered fundamental skills, and how well 

they are able to apply their training in the field are of crucial importance and may reveal 

instructors, courses, or whole curricula that need attention. It is also important to make 

sure that training stays up to date — laws, policies, technology, criminal behavior, social 

conditions, and public concerns are constantly changing.

Some of the specific types of data that law enforcement agencies can use to track and 

monitor training include (1) job-task inventories that provide details about how often 

officers (and other employees) actually perform various tasks; (2) scores on knowledge 

tests that indicate whether learning in any particular areas is insufficient or slipping; 

(3) ratings on performance tests that similarly indicate any skill areas in which training is 
SUGGESTED

READING

Reaves, B.A. 2016. State and 

local law enforcement training 

academies, 2013. Washington, 

DC: U.S. Department of Justice, 

Bureau of Justice Statistics. NCJ 

249784. https://www.bjs.gov/

content/pub/pdf/slleta13.pdf. 

Evidence-Based Policing in 45 Small Bytes 61

not bringing students up to a satisfactory level; (4) student evaluations of courses and 

instructors that provide input about learning conditions, perceived relevance of courses, 

and similar matters; (5) follow-up interviews or surveys with students to get self-reported 

input about how they have (or haven’t) been able to use the training they received; and 

(6) interviews or surveys of supervisors and field training officers (coaches) to get their 

insights, after trainings, about whether staff have demonstrated expected levels of 

proficiency.

How Evidence-Based Is Police Training?

“It has been suggested that what could be reliably said about police training ... would not amount to 

much, because huge gaps exist in our knowledge of the short and long-term effects of various forms 

of police training due to the fact that training techniques, courses and/or whole programs are rarely 

subject to internal or independent evaluation.”

“It is somewhat disconcerting that significant public investments are made each year in this area 

when we know very little about ‘what works’ in police training, including how effectively training 

objectives are being met and what particular techniques work best.”

“To the extent that police agencies frequently borrow ideas, strategies and programs from each 

other that may appear to be unsuccessful, we run the risk of replicating programs that are, from an 

empirical standpoint, untested.”

Source: Huey, L. 2018. “What do we know about in-service police training? Results of a failed systematic review.” London, Ontario, 

Canada: University of Western Ontario, 2, 14-15. https://ir.lib.uwo.ca/cgi/viewcontent.cgi?article=1043&context=sociologypub. 

Evidence-Based Policing in 45 Small Bytes 63

SECTION 5:

Measuring Performance

Measuring performance is an important aspect of evidence-based policing (EBP) 

because police managers and leaders need to know whether individuals, units, 

and systems in the organization are doing what they are supposed to do. This 

involves looking carefully at activities and their immediate outputs. A simple example 

would be focusing on the number of vehicle stops made by the traffic unit (activities) and 

the number of citations issued (outputs). 

Here are three important considerations related to performance measurement:

1. Quality is usually more important than quantity. In regard to the traffic unit, more stops 

does not necessarily indicate better performance, and 10 citations for inoperative tag 

lights is probably not better than 5 citations for texting while driving. 

2. A related point is that activities and outputs should not be confused with outcomes. 

In the traffic example, what ultimately matters are safer roads, safer driving, fewer 

crashes, fewer injuries, and fewer fatalities — not more stops and tickets.

3. However, saying that outcomes are what ultimately matter is not an excuse to 

ignore performance. Organizations, including police agencies, operate on an implicit 

understanding or formal logic model, according to which performing certain activities 

will lead to better outcomes. This explains why measuring performance is a key 

ingredient in EBP. If desired outcomes are achieved, the agency needs to know what 

it did that seemed to work. And if those outcomes are not achieved, it needs to know 

what it was doing that apparently did not work.

Admittedly, the line between outputs and outcomes is not always clear. For example, a 

successful burglary investigation might have several results: suspect identified, suspect 

arrested, case cleared, suspect charged, suspect convicted. Identifying the suspect is 

presumably just an investigation output, whereas gaining a conviction corresponds to 

“holding offenders to account,” one of policing’s bottom-line outcomes presented earlier. 

Whether to count the middle three results — arrest, clearance, and charges filed — as 

outputs or outcomes is less clear-cut. Because this dividing line between outputs and 

outcomes is somewhat murky, the following sections touch on both.
SUGGESTED

READING

Shane, J.M. 2007. What every 

chief executive should know: 

Using data to measure police 

performance. Flushing, NY: 

Looseleaf Law Publications.

64 National Institute of Justice | NIJ.ojp.gov

Jobs, activities, and outputs in police organizations vary widely. Personnel assigned to 

patrol, investigations, tactical units, training, and the communications center do very 

different things. The next few sections hit some of the high points of measuring police 

performance but are certainly not exhaustive.

Intelligent Policing

“Why measure? Well, first and foremost, measurement is necessary to enable us to understand how 

the system is performing, to predict how it will continue to perform into the future, and to identify 

opportunities for improvement. Measurement is critical for ensuring that activity meets purpose, as 

well as for alerting us to warning signals about the emergence of hitherto unseen problems which 

could damage the system.”

“When approaching the subject of measurement, the first thing that managers need to ensure is that 

the right things are being measured. To help identify what these are we need to be absolutely certain 

about purpose. Appropriate measures must be related to purpose, otherwise they risk becoming 

perverse incentives for activity that bears no relation to purpose. Non-value activity (i.e., waste) 

detracts from the system’s capacity for value activity.”

Source: Guilfoyle, S. 2013. Intelligent policing: How systems thinking methods eclipse conventional management practice.

Devon, UK: Triarchy Press, 233, 235
Evidence-Based Policing in 45 Small Bytes 65

BYTE 27

Arrests, Citations, 

Stops, and Searches

One of the most fundamental dimensions of police performance is the use of official 

authority. A substantial focus of police training is on teaching laws and procedures 

of arrest, search, and seizure as well as the practical skills needed to carry out 

such activities safely and effectively. In addition, policies and supervision aim to guide 

officers when they are deciding whether to exercise their authority to stop, cite, arrest, 

or search.

Counting numbers of arrests and citations has long been standard practice in policing, 

made easy by the fact that those activities automatically produce official documents. 

Traditionally, it has been less common to count stops and searches, for two related 

reasons: Most do not produce a tangible output (citation, arrest, or seized property) and, 

at least until recently, most agencies did not require them to be documented on a form 

or other official record. This has changed over the past 20 years, mainly because of 

allegations of unjustified person stops (stop and frisk issues) in some jurisdictions, and 

allegations of disproportionate numbers of vehicle stops and searches based on race or 

ethnicity (often called racial profiling) in many jurisdictions.

Of crucial importance is that these basic components of police performance correspond 

to nearly all of the bottom-line outcomes of policing. One way of illustrating the 

relationships is presented in figure 2. 

Figure 2. Exercises of police authority are directly connected to policing’s bottom line

Arrests

Citations

Stops

Searches

Holding offenders

to account

Using force and authority

fairly and effectively

Reducing serious crime

Maintaining safety and order

Reassuring the public

Using financial resources fairly, 

effectively, and efficiently
66 National Institute of Justice | NIJ.ojp.gov

These activities, outputs, and outcomes can be interrelated in a variety of ways. 

Ideally, stops and searches lead to arrests and citations. These, in turn, result in 

prosecutions and convictions, directly contributing to holding offenders to account and 

indirectly helping to reduce crime, maintain order, and reassure the public. When this is 

accomplished through the fair and effective use of authority, positive outcomes are even 

more likely to be achieved and supported by the public.

Two other scenarios are less ideal. In one case, underenforcement can result in offenders 

not being held accountable, which might lead to increased crime, more disorder, 

and more fear of crime. On the other hand, if police misuse their authority by making 

unjustified, discriminatory, or excessive stops and searches, they risk losing public trust 

and support. In addition, this kind of performance might be ineffective if cases fail to 

result in convictions and would be inefficient if time and resources are wasted on stops 

and searches of nonoffenders or predominantly minor offenders.

The implication of these scenarios is that police agencies need to monitor both the 

quantity and quality of enforcement-related activities and outputs. There is no formula 

or standard for determining how much enforcement is most effective — it’s a judgment 

call. But, at a basic level, a commander needs data that show their agency’s trends 

over time, and that identify individuals and units with particularly low or high levels 

of arrests, citations, stops, and searches. As always, numbers that are well above or 

below the norm may have a logical explanation, and may be indicative of good or poor 

performance. The point is that data can draw attention to unusual levels of performance 

so that they can be reviewed and assessed.

Obviously, it is also essential to look beyond simple aggregate numbers, such as 

counts of arrests or tickets. Here are a few examples of the value of more fine-grained 

performance data:

1. Arrests — If the agency has a mandatory arrest or pro-arrest policy for domestic 

assault (or if it is governed by similar state law), data can indicate how well individual 

officers, units, and the agency as a whole are in compliance.

2. Citations — Data can indicate the degree to which individual officers and units are 

issuing tickets for the kinds of infractions that are the main causes of crashes in the 

jurisdiction, and also whether they are targeting the most crash-prone locations.

3. Stops — Data can indicate whether any demographic subgroups are 

disproportionately represented in person stops and vehicle stops. If significant 

disparate impact is observed, comparing individual officers in similar assignments is 

one way of exploring what might be causing the differences.

4. Searches — Data on the “hit rate” in searches of persons and vehicles can indicate 

whether some individual officers or units might be more prone to unsubstantiated 

searches than others. Similarly, some officers might make much greater use of 

consent searches than others. If the hit rate on these searches is low, questions might 

be raised about whether the officers are using their authority fairly and effectively — 

especially if there is demographic disparity of the people they seek consent to search.
SUGGESTED

READING

White, M.D., and H.F. Fradella. 

2016. Stop and frisk: The use 

and abuse of a controversial 

policing tactic. New York: New 

York University Press.

Evidence-Based Policing in 45 Small Bytes 67

Many other indicators of performance quality can be used. An officer who places more 

charges of resisting arrest than his or her colleagues may need training or counseling. 

A unit that issues an above-average number of seat belt, texting while driving, or 

driving under the influence citations may have discovered tactics or techniques that 

should be shared with others — those are drivers’ behaviors specifically connected to 

risk and harm. Police agencies should be creative in establishing enforcement-related 

performance measures that guide officers toward the kinds of activities and outputs that 

are most likely to enhance the achievement of “bottom line” policing outcomes.

Performance Metrics

“The important question for implementing evidence-based policing is not whether performance 

metrics should exist, but rather what performance metrics are used and do some of them reflect 

values and knowledge from an evidence-based policing approach? The choice of performance 

metrics matters and is both a reflection and reinforcement of an agency’s philosophical approach 

to policing and its sought-after outcomes. For example, if the number of arrests and citations 

that an officer makes are used to judge her performance, then this will reinforce her using arrest 

and citation as her primary crime-fighting strategy. However, if that same officer is judged by the 

amount of proactive problem-solving activities she engages in, then her crime-fighting strategy will 

be different.”

Source: Lum, C., and C.S. Koper. 2017. Evidence-based policing: Translating research into practice. Oxford: Oxford University 

Press, 240-241.
68 National Institute of Justice | NIJ.ojp.gov

BYTE 28

Use of Force 

and Pursuits

T

wo elements of police performance that bear directly on the bottom-line outcome 

of “using force and authority fairly and effectively” are use of force and vehicle 

pursuits. Both of these police activities are authorized by law and are often 

necessary in order to protect victims, interrupt crimes in progress, arrest offenders, 

maintain public safety, and restore order in the face of conflict. However, it is also true 

that police authority to use force is limited under law, using force and engaging in vehicle 

pursuits entails risks, and public support for these activities cannot be taken for granted. 

Although statutory and policy language varies from place to place, it is generally agreed 

that in any particular situation police should use the least amount of force necessary to 

accomplish lawful objectives, making it particularly important to track and monitor these 

elements of performance.

Monitoring performance in this domain is aided by the fact that it is now common 

practice for law enforcement agencies to require officers to complete use-of-force and 

vehicle-pursuit reports. Separate from any internal investigations that may be conducted 

to determine whether specific actions were justified, data from these reports can readily 

be compiled in order to look for patterns and trends. 

Use-of-force reporting generally provides incident-level information that includes the 

type of encounter, the threat or resistance faced by the officer, the type and level of force 

applied, the severity of any injuries suffered, and the outcome of the encounter. Agencies 

have several decisions to make, though, regarding specific details of their reporting system:

1. The minimum threshold for reporting. Most agencies do not count routine handcuffing 

or mere “hand on the shoulder” touching as use of force, but just where to draw the 

line for required reporting varies.

2. A related issue is whether to include threats as use of force, such as threatening to 

deploy oleoresin capsicum (pepper spray) or a conducted energy device (e.g., Taser). 

Most agencies do not require reporting of mere threats to use force, but there is some 

concern that flagrant use of threats can have a corrosive effect on police-community 

relations.
SUGGESTED

READING

Rojek, J., J. Nix, S. Wolfe, G. 

Alpert, J. Burch, J. Grieco, and 

T. Robbins. 2019. Analysis of 

2018 use of deadly force by 

the Phoenix Police Department.

Washington, DC: National 

Police Foundation. https://

www.phoenix.gov/policesite/

Documents/NPF_OIS_Study.pdf. 

Evidence-Based Policing in 45 Small Bytes 69

3. Regarding conducted energy devices, some but not all agencies require reporting if 

the device’s laser dot is “painted” on a subject.

4. Regarding firearms, some but not all agencies require reporting if the weapon is 

displayed and/or pointed at a subject.

Agencies can readily examine their use-of-force data to see, for example, what particular 

types of force are being used more or less often, whether levels of use vary across 

geographic areas or organizational units, or whether certain types of suspect resistance 

are changing. One common metric is the proportion of arrests involving the use of force, 

and another is the proportion of all police-citizen encounters that include police use of 

force. For the latter, a national estimate from surveys of the public is that about 1% of 

encounters result in police using some level of force beyond threats or handcuffing.26

Monitoring vehicle pursuits presents similar issues and considerations. Agencies usually 

collect several pieces of information related to pursuits, such as the initial reason for 

attempting to stop the vehicle (traffic offense, property crime, violent crime), the duration 

of the pursuit, vehicle speeds, whether the pursuit was terminated by the officer or a 

supervisor, and the outcomes of the pursuit (arrests, crashes, injuries, deaths). As with 

use of force, tracking pursuit-related data can identify any patterns or trends that might 

deserve further analysis.

Use of Force in the New York City Police Department

The New York City Police Department (NYPD) had 7,369 reportable uses of force in 2017. Of those, 

6,071 “involved the minimal amount of reportable force: hand strikes, foot strikes, and forcible 

subduing of subjects. There were also 728 CEW [conducted energy weapon] discharges, 324 

discharges of OC [oleoresin capsicum] spray, 105 uses of impact weapons, 82 uses of mesh blankets 

to control subjects, 52 firearms discharges, and seven canine bites.” A total of 9,213 subjects were 

involved in the use-of-force incidents, of whom only 372, or 4%, required any hospital treatment. For 

2017, uses of force occurred in about 1% of all arrests.

The NYPD’s report also provides historical comparisons (e.g., firearm discharge incidents have 

dropped 95% since 1972) and breaks out the data by use-of-force category, type of incident, police 

precinct, and officer and subject race/ethnicity.

Source: Adapted from New York City Police Department. 2018. Use of force report 2017. https://www1.nyc.gov/assets/nypd/

downloads/pdf/use-of-force/use-of-force-2017.pdf. 

26 Davis, E., A. Whyde, and L. Langton. 2018. Contacts between police and the public, 2015. Washington, DC: U.S. 

Department of Justice, Bureau of Justice Statistics, 17. NCJ 251145. https://www.bjs.gov/content/pub/pdf/cpp15.pdf. 
70 National Institute of Justice | NIJ.ojp.gov

BYTE 29

Public Contacts, 

Community Engagement, 

and Problem Solving

Most law enforcement agencies expect their officers to make frequent 

nonenforcement public contacts, collaborate with individuals and community 

groups, and undertake problem solving to address chronic crime and disorder 

issues. These kinds of activities correspond to community-oriented policing (COP) and 

problem-oriented policing (POP), which remain popular policing strategies for good 

reason. Studies have shown that COP has positive effects on the public’s satisfaction 

with police services and perceptions of disorder,27 and POP has a significant impact on 

reducing crime and disorder.28

Public contacts, community engagement, and problem solving are not very easy to 

measure, however, since they don’t routinely generate reports, legal documents, or other 

tangible products that are easily counted. Nevertheless, since these kinds of activities are 

positively associated with several bottom-line policing outcomes, agency leaders need 

to know how often these activities are being carried out, how effectively they are being 

implemented, and whether some units are doing better than others.

Because of their nature, these activities are best measured more qualitatively:

1. Public contacts — Supervisors can periodically accompany officers on patrol and/

or review samples of body-worn camera footage to observe and rate nonenforcement 

public contacts. Simple scales can be used to rate officers on a few items such as 

“takes advantage of opportunities for public contact,” “communicates in a positive 

and friendly manner,” and “listens carefully to citizens’ concerns.” 

2. Community engagement — Supervisors can elicit examples of community 

engagement from their officers, rate them on simple criteria such as depth of 

involvement, and also recontact the citizens involved to get their input on the quality 

and value of the engagement efforts reported by officers.

27 Gill, C., D. Weisburd, C.W. Telep, Z. Vitter, and T. Bennett. 2014. “Community-oriented policing to reduce crime, 

disorder and fear and increase satisfaction and legitimacy among citizens: A systematic review.” Journal of 

Experimental Criminology 10 no. 4 (December). https://link.springer.com/article/10.1007%2Fs11292-014-9210-y. 

28 Weisburd, D., C.W. Telep, J.C. Hinckle, and J.E. Eck. 2008. “The effects of problem-oriented policing on crime and 

disorder.” Campbell Systematic Reviews (October). https://www.campbellcollaboration.org/images/meeting/1045_R.pdf. 
SUGGESTED

READING

Wycoff, M.A., and T.N. 

Oettmeier. 1994. Evaluating 

patrol officer performance 

under community policing: 

The Houston experience. 

Research Report. Washington, 

DC: U.S. Department of 

Justice, National Institute of 

Justice. NCJ 142462. https://

www.ncjrs.gov/pdffiles1/

Digitization/142463NCJRS.pdf. 

Evidence-Based Policing in 45 Small Bytes 71

3. Problem solving — Some agencies have POP forms that officers fill out when they 

engage in significant problem-solving activity. The information in those forms, or the 

verbal reports that officers provide about their problem-solving activity, can be scored 

using established criteria based on the well-known “scanning, analysis, response, 

assessment” (SARA) model of problem-oriented policing. Criteria for scoring problem 

solving could include “evidence that the analysis has in fact influenced the way in 

which the police and others think about and respond to the problem” and “evidence 

that at least several alternative responses were considered and an explanation as to 

why some responses were implemented and others not.”29

This is a good place to mention how important it is to strike a careful balance in 

performance measurement. On one hand, an agency’s leaders must be provided with 

reliable information about what activities are being performed by members of the 

organization, and how well those activities are being performed. This kind of information 

is crucial for effectively guiding the agency and maximizing its achievement of important 

outcomes. On the other hand, though, it can be exhausting trying to measure everything 

all the time. If agency supervisors and other staff are forced to spend all their time 

measuring performance, other responsibilities will suffer.

In regard to key aspects of performance, especially those that are hard to measure — 

such as public contacts, community engagement, and problem solving — agency 

leaders should regularly ask two questions: “How are we doing,” and “How do we 

know?” Consistently posing these questions reinforces the importance of the activities 

and also challenges members of the organization to demonstrate that they are genuinely 

attuned to the important high-priority activities.

Beat-Level Problem Solving in Chicago

“Police all over the city — not just officers assigned to special units or with special training and 

resources — were supposed to get involved in problem-solving at the beat level ... . In too many 

beats, the same problems persisted year after year even though they had been identified as priorities 

... [W]e gave the department a ‘C’ for its problem-solving efforts.”

“Asking both police and residents revealed that most of what the police were up to was extremely 

traditional. As in other cities, police rarely gathered ‘data’ of any kind except what they observed 

in the field, and they mostly applied traditional enforcement tactics, such as driving by more often, 

stopping cars, and trying to arrest people. But both police and residents reported broader public 

involvement in a range of problem-solving activities, including organizing block clubs, forming 

patrols, mobilizing city services, and trying to awaken their apathetic neighbors to the problem.”

Source: Skogan, W.G. 2006. Police and community in Chicago: A tale of three cities. Oxford: Oxford University Press, 210.

29 See https://popcenter.asu.edu/goldstein. 
72 National Institute of Justice | NIJ.ojp.gov

BYTE 30

Response Time

R esponse time is a performance measure that has been used by law enforcement 

agencies for decades. At one time, a common objective was to keep response time 

to reported crimes as short as possible, based on the assumption that quick arrival 

improved the chances of catching the offender. However, an important study in the 1980s 

revealed a major flaw in this logic — about three-quarters of reported crimes are cold 

before they are ever discovered. In addition, even when someone (a victim or witness) is 

aware of the crime while it is happening, they tend to delay several minutes before calling 

the police or 911. Because of these realities, quick police response to reported crimes 

results in an arrest at or near the scene in only about 3% of cases.30

Despite these rather discouraging findings, rapid response can sometimes make a 

difference, depending on the circumstances. When a crime is reported while in progress, 

or right afterward, quick response does significantly improve the chances of an 

apprehension. Also, many incidents that are not necessarily serious crimes might merit a 

quick police response, such as a fight, a suspicious person, a traffic crash, or a medical 

emergency. 

The modern approach is to categorize the calls coming into the communications center 

and set criteria to determine which calls should get an immediate police response and 

which ones can be handled in other ways, such as delayed response, response by 

nonsworn personnel, telephone reporting, or online reporting. Performance measures 

should then be aligned with the categories so that the agency can track its response 

time to high-priority calls separately from the rest. Median response time to highpriority incidents can be monitored over time for the agency as a whole and can also be 

examined by time of day and for geographic sections of the jurisdiction. Tracking these 

measures helps the agency assess its staffing needs and also provides guidance for 

proper allocation and deployment of existing personnel.

Modern technology, especially computer-aided dispatching systems, makes it relatively 

easy to measure and track response times. For the data to be meaningful, they should 

be broken out by call priorities, as mentioned. In addition, three main components of 

response time should be measured and reported separately:

1. Answering time — The elapsed time from when the incoming call rings at the 

communication center until it is answered.

30 Spelman, W., and D.K. Brown. 1984. Calling the police: Citizen reporting of serious crime. Washington, DC: U.S. Department 

of Justice, National Institute of Justice. NCJ 82276. https://www.ncjrs.gov/pdffiles1/Digitization/82276NCJRS.pdf. 
SUGGESTED

READING

Spelman, W., and D.K. 

Brown. 1984. Calling the 

police: Citizen reporting of 

serious crime. Washington, 

DC: U.S. Department of 

Justice, National Institute of 

Justice. NCJ 82276. https://

www.ncjrs.gov/pdffiles1/

Digitization/82276NCJRS.pdf. 

Evidence-Based Policing in 45 Small Bytes 73

2. Dispatching time — The elapsed time from when the incoming call is answered until 

it is assigned to a patrol unit for response.

3. Travel time — The elapsed time from when the call is assigned to a patrol unit until 

the unit arrives at the scene of the incident.

The purpose of measuring all three components is to monitor and detect sources 

of delay, particularly for high-priority calls. Delays can occur for many reasons — 

overloaded telephone systems, too few staff answering the phones, system breakdowns 

between phone operators and dispatchers, too few dispatchers, too few patrol units, 

spikes in patrol workload, traffic congestion, long travel distances for responding units, 

and so on. Careful measurement can help identify and diagnose the sources of delay, 

providing clues for how to minimize them in order to keep response times to priority calls 

as short as possible.

Response Time in Detroit

In 2013, average response time to Priority 1 calls in Detroit was over 50 minutes. After implementing 

a more rigorous call priority system, reallocating patrol staff based on workload, and adding GPS 

monitoring of patrol vehicle location, the police department brought the average response time down to 

14.5 minutes in 2017, despite a decrease in the overall number of officers. The agency tracks average 

priority response times in different areas of the city as well, and it is able to keep variation within fairly 

close limits. Responding more quickly to higher priority incidents, though, means that people reporting 

lower priority incidents have had to wait longer. The end result, according to an assistant chief, is that 

“We’re just a little bit smarter in how we police.”

Source: Adapted from Wilkinson, M. 2017. “Detroit police improve response times. But not all neighborhoods are equal.” 

Bridge (October 3).
74 National Institute of Justice | NIJ.ojp.gov

BYTE 31

Crime Clearances and 

Judicial Outcomes

When crimes against persons or property occur, victims and society at large 

hope that they will be solved by the police. If police are successful at solving 

crimes, perpetrators can be held accountable, other offenders may change their 

behavior based on a heightened expectation of getting caught (i.e., deterrence), and the 

public may be reassured that justice will be done and crime doesn’t pay. Of course, the 

opposite effects can be anticipated if police are not very successful at solving crimes. 

The clearance rate for Part I crimes is the traditional measure of investigative 

performance. As defined in the FBI’s Uniform Crime Reporting (UCR) system, a crime is 

cleared when a perpetrator has been arrested and charged, or when an identified and 

located perpetrator can’t be arrested through no fault of the law enforcement agency, 

such as when the perpetrator has died, the victim refuses to cooperate, or another 

jurisdiction is prosecuting the individual and won’t release him or her for extradition. 

(These are called exceptional clearances.)

The clearance rate is a very useful measure of agency performance because it is well 

understood, has been used for years, and national averages are published annually, 

broken out by crime type and size of department. This allows an agency to track its 

performance over time and in comparison to benchmarks, making it possible to identify 

trends, areas of strength, and areas in need of improvement.

The clearance rate has shortcomings, however. When a crime is cleared based on the 

official UCR criteria, it still might be true that other perpetrators (accomplices) were 

not caught, stolen property was not recovered and returned to its owner, the arrested 

perpetrator was not prosecuted, and/or the arrested perpetrator was not convicted. If 

any of these conditions prevail in spite of clearance criteria being met, it is easy to see 

that success in holding offenders accountable, reducing crime, and reassuring the public 

has been limited. Police might declare a “win” having cleared the case, but it would be a 

partial victory at best.

As a result, it is recommended that agencies utilize some additional measures in 

conjunction with the Part I crime clearance rate, such as the following:

1. The value of recovered and returned stolen property in Part I crimes as a percentage 

of the total value of Part I stolen property.
SUGGESTED

READING

Federal Bureau of Investigation. 

2018. “Clearances.” Crime 

in the United States, 2017.

Washington, DC: U.S. 

Department of Justice, 

Federal Bureau of Investigation, 

Uniform Crime Reporting 

Program. https://ucr.fbi.gov/

crime-in-the-u.s/2017/crimein-the-u.s.-2017/topic-pages/

clearances. 

Evidence-Based Policing in 45 Small Bytes 75

2. The clearance rate for selected Part II crimes, such as assault, vandalism, and fraud. 

These are offenses that occur frequently, have real victims, and therefore matter 

greatly to the public, even though they don’t count as Part I crimes.

3. The prosecution rate for Part I and Part II arrests. These should include drug, 

disorderly conduct, and DUI offenses, which often represent a high proportion of all 

arrests. If prosecution (or conviction) rates for these are low, the agency needs to 

know so that it can look for explanations and possible remedies.

4. The conviction rate for Part I and Part II arrests.

Some agencies may have difficulty obtaining information on prosecution and conviction 

outcomes, either because prosecutors and courts have antiquated record systems or 

because they are reluctant to be transparent and collaborative. This information is so 

significant, though, that law enforcement agencies should be forceful in demanding 

the data. Without knowing what becomes of arrests, neither the police nor the 

public can assess how well offenders are being held accountable. Moreover, if there 

are shortcomings in investigative performance that are interfering with successful 

prosecution and adjudication, they cannot be identified and corrected without this 

information.

It can be argued that prosecution and conviction rates are unfair measures for assessing 

police performance, since they reflect decisions made by other officials. This is true on 

the surface but misses the point in two important ways. First, these data are needed 

in order to determine whether there is a problem; if the rates are lower than expected, 

then the next step is to figure out why. If some of the explanation is poor investigative 

performance, the agency needs to know that in order to fix it. Alternatively, if the 

explanation is shortcomings in prosecution or the court, agency leaders need to know 

that in order to advocate for improvements in those offices. The second reason why the 

data on prosecution and conviction rates are needed is that, ultimately, they’re what 

matter most. A good clearance rate is not contributing very much to the policing bottom 

line if offenders aren’t being prosecuted and found guilty.

Clearance Rates in Scottsdale, Arizona

In its annual report, the Scottsdale Police Department presents Part I crime clearance rates by crime 

type for the past 15 years. Clearance rates for the three high-volume crimes of burglary, theft, 

and auto theft have steadily increased over that period, with the biggest improvement in burglary 

clearances, which are up from 10% in 2004 to 24% in 2018. The report also compares Scottsdale 

to national and state averages. The department’s overall Part I clearance rate of 26.9% for 2018 

exceeded the U.S. and Arizona averages, which were 21.6% and 20.4%, respectively.

Source: Adapted from Scottsdale Police Department. 2019. “2018 Uniform Crime Report highlights.” https://www.scottsdaleaz.

gov/Assets/ScottsdaleAZ/Police/statistics/2018-spd-ucr-highlights.pdf. 
76 National Institute of Justice | NIJ.ojp.gov

BYTE 32

Civil Suits and 

Judgments

I

t is not unusual for law enforcement agencies to be sued for actions taken or not taken 

by their personnel. These civil suits may be brought in state or federal court, with the 

latter alleging some breach of U.S. constitutional rights. When suits are brought, they 

generally seek to include the agency and its parent government, not just the individual 

officer or officers directly involved. Most commonly, suits claim that the agency failed to 

adequately screen, train, supervise, direct, and/or control the officer(s), which allowed 

or caused them to engage in the improper behavior, resulting in harm to the plaintiff. 

Of course, connecting the behavior to agency negligence gives the plaintiff access to 

“deeper pockets,” that is, the parent government’s coffers and insurance coverage.

Civil suits like these are relevant to police performance and the policing bottom line in 

several ways:

1. Since they are potentially quite costly, they may bear directly on “using financial 

resources fairly, efficiently, and effectively.” Funds that have to be paid to successful 

plaintiffs, even when partially covered by insurance, are essentially wasted (not 

available to be spent on public services) and may be taken out of the police agency’s 

budget, directly or indirectly.

2. Most civil suits arise out of arrest and use-of-force situations (including vehicle 

chases). Thus, they reflect on the bottom-line outcome “using force and authority fairly 

and effectively.”

3. When civil suits are successful, and especially if they are well publicized, they may 

affect the bottom-line dimension of “reassuring the public.” Too much news about 

police misconduct, and about millions of tax dollars being paid out as a result, does 

not give residents much assurance that their police are performing professionally and 

effectively.31

Agencies are well advised, then, to collect data on civil suits filed against them. Data 

on civil suits and their costs are directly pertinent to the “using financial resources fairly, 

efficiently, and effectively” bottom-line outcome; thus, they should be monitored and 

tracked as a key indicator of how well that outcome is being achieved. In addition, 

31 Gonen, Y., J. Marsh, and B. Golding. 2018. “NYC has shelled out $384M in 5 years to settle NYPD suits.” New York Post

(September 4); and Newman, J. 2019. “Chicago spent more than $113 million on police misconduct lawsuits in 2018.” The 

Chicago Reporter (March 7).
SUGGESTED

READING

Newman, J. 2019. “Settling for 

misconduct: Police lawsuits in 

Chicago.” The Chicago Reporter. 

Evidence-Based Policing in 45 Small Bytes 77

tracking the types of performance that give rise to litigation is relevant for identifying 

patterns and trends in officer behavior that may need to be examined more closely. In 

this respect, agencies should use data from civil suits in the same way as data from 

citizen complaints — this information may signal behavior or conditions that need 

attention, and identifying them sooner rather than later may prevent additional problems 

from occurring.

Three important points should be emphasized. First, the mere fact of being sued is not 

necessarily indicative of serious problems. Anyone can file a civil suit, no matter how 

groundless, and some jurisdictions may have zealous attorneys who further encourage 

litigation. Second, and related, many civil actions are settled out of court by lawyers for 

the government or an insurance company — even when the plaintiff’s case against the 

police agency is weak — as a way of minimizing the chances of a big jury award. And 

third, data on civil suits can be difficult to gather and assess, in part because cases often 

are not resolved until several years after the disputed event, and also because out-ofcourt settlements in particular are sometimes sealed and therefore secret. 

Despite these limitations, data on civil suits, judgments, and settlements can contribute 

to tracking and monitoring performance and should not be overlooked. 

Judgments and Settlements in New York City

As of 2018, New York City had paid out $384 million over five years in judgments and settlements in 

civil cases against the police department. During that period, the city settled over half of the 11,404 

civil suits brought against the department, most for $20,000 or less in cases alleging false arrest, 

pushing, shoving, or disrespect. In 2015, the city administration promised a crackdown on “nuisance 

lawsuits” by refusing to settle. Since 2016, the annual number of suits filed against the police 

department has dropped by half, while the number taken to trial has increased by 30%.

Source: Adapted from Gonen, Y., J. Marsh, and B. Golding. 2018. “NYC has shelled out $384M in 5 years to settle NYPD suits.” 

New York Post (September 4).

Evidence-Based Policing in 45 Small Bytes 79

SECTION 6:

Identifying and 

Analyzing Problems

T

he previous four sections emphasized the importance of data — data about the 

current status of bottom-line outcomes and about external conditions, internal 

conditions, and performance. Without good information on these matters, 

evidence-based policing is not possible. With such information, a solid foundation is 

in place.

The next step is to identify and then analyze gaps, weaknesses, and problems. 

Identifying problems should be fairly straightforward — as long as the data collection is 

systematic, up to date, and reliable. Modern information technologies, including record 

management systems (RMS) and computer-aided dispatching (CAD), have greatly 

improved data availability in law enforcement agencies. When indicators and metrics 

are in place, agencies can easily see if crime, arrests, traffic crashes, officer safety, 

employee turnover, and use of force are up or down. Metrics can also reveal whether 

fear of crime, public trust, community engagement, and police morale are getting better 

or worse, although data about such conditions are not routinely produced through RMS, 

CAD, or other traditional information systems. As discussed, extra effort is required to 

measure conditions like these, but since they are directly tied to key outcomes and police 

effectiveness, such effort is worthwhile and should be standard operating procedure.

Compared to identification, analysis is not as straightforward. It is one thing to recognize 

that robberies are up, or that fewer officers are applying for promotion, but it is usually 

harder to figure out why. Answering “why” is at the core of analysis. Asking this key 

question produces insights about what is going on and often provides guidance toward 

fixing the problem and improving outcomes.

Along the way to diagnosing a problem, analysis also tries for more precision in answering 

“what” and “how.” If thefts of vehicles have increased, for example, figuring out what 

kinds of vehicles are being stolen, together with when and where, as well as the methods 

being used to enter and start the stolen vehicles, would be very useful. In this case, 

why people steal might seem pretty obvious, but determining whether the thefts are for 

immediate transportation (joy riding), resale, use in the commission of other crimes, or 

disposal through chop shops would be of definite value when trying to choose the best 

prevention and investigation responses for stemming the problem.

The next few sections look a bit more closely at analyzing outcomes, external and internal 

conditions, and performance.
SUGGESTED

READING

Scott, M.S. 2015. Identifying 

and defining policing problems. 

Problem-Solving Tools Series. 

Problem-Oriented Guides for 

Police No. 13. Washington, DC: 

U.S. Department of Justice, 

Office of Community Oriented 

Policing Services. https://cops.

usdoj.gov/RIC/Publications/

cops-p323-pub.pdf. 

80 National Institute of Justice | NIJ.ojp.gov

Recognizing Problems

“Some policing problems are readily apparent because the volume of incidents or the harm being 

caused by them is so great and so public. A sudden spate of violent sexual assaults reported to 

police, for example, could readily compel police to not only work to solve the cases, but to reexamine 

the whole community response to preventing and responding to violent sexual assaults. But many 

policing problems are not so readily apparent. They might be hidden among the many incidents and 

cases police are handling, perhaps classified in different reporting categories, occurring in a wide 

range of locations, or affecting different people. Each incident or case might seem relatively minor 

in its own right, but prove to be more significant when aggregated into a larger problem. Don’t 

assume that if a problem were significant, it would be obvious to everyone. Many police agencies 

have discovered that their officers have been handling similar incidents for years or even decades, 

usually with little or only temporary success, without anyone recognizing the persistent nature of the 

problem and the need to address it as a problem rather than as a string of isolated incidents. Often 

times, because so many different police officers handle these incidents, no one officer recognizes the 

persistence of the problem.”

Source: Scott, M.S. 2015. Identifying and defining policing problems. Problem-Solving Tools Series. Problem-Oriented 

Guides for Police No. 13. Washington, DC: U.S. Department of Justice, Office of Community Oriented Policing Services, 13. 

https://cops.usdoj.gov/RIC/Publications/cops-p323-pub.pdf. 
Evidence-Based Policing in 45 Small Bytes 81

BYTE 33

Analyzing BottomLine Outcomes

As a reminder, these are the bottom-line outcomes of policing:

• Reducing serious crime 

• Holding offenders to account 

• Maintaining safety and order 

• Reassuring the public 

• Providing quality services 

• Using force and authority fairly and effectively 

• Using financial resources fairly, efficiently, and effectively.

An evidence-based law enforcement agency will collect data so that it knows where it 

stands in relation to each of these important outcomes. With data, whenever any of the 

outcomes are slipping, or simply not at an acceptable level, the agency will be able to 

recognize the situation sooner rather than later. Having these data routinely available also 

helps the agency respond to inquiries and criticism and contributes to both short-term 

and long-term planning. 

Besides looking at changes over time in relation to these outcomes, agencies should 

seek out relevant benchmarks. Typical sources of benchmarks are national or regional 

averages and professional standards. For example, a municipal agency serving a 

population in the 10,000-25,000 range could easily determine from the FBI Uniform 

Crime Reporting program that similar-sized agencies nationally experienced a 0.3% 

increase in Part I violent crimes from 2016 to 2017, and in 2017 had an average Part I 

violent crime rate of 2.68 per 1,000 residents, with a 51.9% clearance rate for those 

crimes.32 Naturally, each agency’s circumstances are different, but having benchmarks 

like these provides some basis for comparison and is crucial for recognizing anomalies 

and problems that deserve closer scrutiny. 

32 Federal Bureau of Investigation. Crime in the United States, 2017. 2018. Washington, DC: U.S. Department of 

Justice, Federal Bureau of Investigation, Uniform Crime Reporting Program. https://ucr.fbi.gov/crime-in-the-u.s/2017/

crime-in-the-u.s.-2017. 
82 National Institute of Justice | NIJ.ojp.gov

Analysis comes into play when an agency needs to take a closer look at outcomes that 

aren’t being achieved at an acceptable level. If that hypothetical municipal agency in the 

10,000-25,000 population range had a big increase in Part I violent crimes when most 

other similar-sized agencies didn’t, for example, analysis would be aimed at figuring 

out why. One analytical approach would be to disaggregate the problem to see which 

types of violent crime accounted for the increase. Similarly, analysis would check to 

see whether the increases occurred across the jurisdiction, or if they were concentrated 

geographically. Analysis could also consider potential explanations (e.g., increased 

unemployment, increased drug addiction, turf disputes between gangs) and then 

examine data to see which explanations could be ruled out in that jurisdiction.

Analysis like this might not be able to pinpoint with certainty the exact causes of a crime 

increase, but it can usually narrow the range of likely explanations while also producing 

a richer understanding of the problem. In a recent real-life example, Phoenix, Arizona, 

experienced a substantial rise in officer-involved shooting (OIS) incidents during 2018, 

bringing into question whether it was “using force and authority fairly and effectively.” 

Analysts took a detailed look at the shooting incidents and also considered whether 

anything within the agency — such as training or policies — or within the community 

could have contributed to the abrupt increase. Comparisons were made to other big 

cities, and to other jurisdictions in Arizona, to see if the agency’s rate of OIS incidents per 

officer or per violent crime was higher, about average, or lower than in other agencies. 

The analysis yielded several important insights that helped the police department and 

community put its situation in perspective. For example, OIS incidents had spiked in 

Phoenix twice before in the previous decade, so 2018 wasn’t a unique year. Also, several 

neighboring jurisdictions saw sharp increases in 2018, suggesting that it was not simply 

a Phoenix phenomenon. Finally, analysis revealed “an increase in subjects armed with 

firearms or simulated firearms involved in OIS encounters, and a significant increase in 

reported assaults on officers, specifically assaults on officers involving firearms.”33

Analysis doesn’t always lead directly to an obvious answer to why a problem is growing 

or has stubbornly persisted, nor to a guaranteed solution to the problem. But analysis 

ordinarily does help the agency diagnose and understand the problem better, which can 

be the key to moving forward effectively. That was the case in the well-known Boston 

Gun Project. Facing a significant increase in youth murders (up 230% from 1987 to 

1990), Boston officials initially thought they faced a massive citywide challenge. Then, 

analysis revealed that the number of active shooters and shooting victims was really 

fairly small, confined to a few gangs. With that discovery, the problem became much 

more manageable, and a targeted violence prevention approach turned out to be very 

successful.34

33 Rojek, J., J. Nix, S. Wolfe, G. Alpert, J. Burch, J. Grieco, and T. Robbins. 2019. Analysis of 2018 use of deadly 

force by the Phoenix Police Department. Washington, DC: National Police Foundation, 60. https://www.phoenix.gov/

policesite/Documents/NPF_OIS_Study.pdf. 

34 Boston Police Department. 1998. “Operation Cease Fire: Deterring youth firearm violence.” https://popcenter.asu.

edu/sites/default/files/library/awards/goldstein/1998/98-08(W).pdf. 
SUGGESTED

READING

Brodeur, J.-P., ed. 1998. How 

to recognize good policing: 

Problems and issues. Thousand 

Oaks, CA: Sage.

Evidence-Based Policing in 45 Small Bytes 83

Asking the Right Question

“Above all, the critical question for strategic products is ‘why.’ This is in part because investigators 

generally don’t have to answer ‘why ecstasy?’ in order to secure a conviction or seizure, whereas 

knowledge of what, when, where and how are essential at the tactical level. Understanding why 

criminals smuggle particular commodities or commit certain crimes as opposed to others indicates 

not only the underlying causes of a threat and thus how law enforcement could intervene, but also 

provides pointers for law enforcement’s priorities.”

Source: Higgins, O. 2004. “Rising to the collection challenge.” In J.H. Ratcliffe, ed., Strategic thinking in criminal intelligence.

Alexandria, NSW, Australia: The Federation Press, 74.
84 National Institute of Justice | NIJ.ojp.gov

BYTE 34

Analyzing External 

Conditions

When the term analysis is mentioned in law enforcement circles, thoughts 

immediately go to crime analysis. This is a positive sign that the value of crime 

analysis has become widely recognized in the policing world. The downside 

is that other types of analysis sometimes get overlooked. One exception is intelligence 

analysis, which has gained substantial support and higher priority since the 9/11 terrorist 

attacks. But it is important to realize that all the external conditions for which police bear 

some degree of responsibility — including disorder, traffic safety, fear of crime, substance 

abuse, mental health crises, citizen complaints, client satisfaction, and public trust — 

are logical targets of analysis. There isn’t a generally accepted term that captures the 

full range of these types of analysis, but some have suggested problem analysis as one 

option for reminding agencies that they need a wider lens than just crime analysis.35

If agencies have data on each of these relevant external conditions, as they should, 

they will be alerted to any troubling changes. Part of analysis is to keep an eye on these 

data, looking for patterns as well as trends. For example, overall public trust might be 

steady, yet slipping among some subgroups of the population. Total traffic crashes 

might be down, masking an increase in pedestrian or bicycle injuries. Overdoses 

might be decreasing following the peak of the recent opioid crisis, but fentanyl-related 

methamphetamine and cocaine overdoses might be rising. One job for analysis is to spot 

these kinds of shifting patterns as early as possible in order to inform agency responses.

When trends and new patterns are identified, the next task for analysis is to figure out 

what’s going on. This goes back to the “why” question — Why is public trust slipping 

among some segments of the population? Why are traffic crashes involving pedestrians 

increasing? Answers to these kinds of questions can sometimes be found in the data, 

but analysts may also find it necessary to make observations out in the community, 

interview people (including offenders), administer surveys, and use other informationgathering techniques. They may need to use tools such as GIS (geographic information 

systems), statistical analysis, content analysis, social network analysis, and repeat 

victimization analysis. 

35 Boba, R. 2003. Problem analysis in policing. Washington, DC: Police Foundation. https://popcenter.asu.edu/sites/

default/files/library/reading/pdfs/problemanalysisinpolicing.pdf. 
SUGGESTED

READING

Clarke, R.V., and J.E. Eck. 

2005. Crime analysis for 

problem solvers in 60 small 

steps. Washington, DC: U.S. 

Department of Justice, Office 

of Community Oriented Policing 

Services, Step 6. https://

www.popcenter.org/sites/

default/files/library/reading/

PDFs/60Steps.pdf. 

Evidence-Based Policing in 45 Small Bytes 85

One crucial insight that applies particularly to crime analysis, but is relevant to other 

analyses too, is to focus carefully on specific problems. Most of the external conditions 

that police are charged with handling — crime, disorder, fear, safety, and so on — 

are each fairly broad categories. Crime, for example, includes hundreds of different 

behaviors, from tax evasion and disorderly conduct to child abuse and murder. Even a 

single statutory category like robbery includes bank robberies, street robberies, robberies 

of taxi drivers, robberies of drug dealers, and home-invasion robberies — each type 

having important differences in how the robberies are carried out, who usually commits 

them, and how dangerous they are for victims. 

Disaggregating problems when analyzing them is essential for really figuring them out. 

Otherwise, attempts to analyze overly broad categories run the risk of “lumping apples 

and oranges together,” which gets in the way of understanding each type individually. 

When that happens, a typical consequence is a blended response that doesn’t fit any 

of the component parts of the problem as well as it should and thus isn’t very effective. 

The policing and crime prevention fields now have substantial evidence showing that 

what works best are targeted responses — and the foundation for these is carefully 

targeted analysis.

Zeroing In on the Problem

“Breaking down a larger problem of crime into smaller categories is merely the first step in 

tightening the focus of a POP [problem-oriented policing] 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. 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.”

Source: Clarke, R.V., and J.E. Eck. 2005. Crime analysis for problem solvers in 60 small steps. Washington, DC: U.S. 

Department of Justice, Office of Community Oriented Policing Services, Step 6. https://www.popcenter.org/sites/default/files/

library/reading/PDFs/60Steps.pdf. 
86 National Institute of Justice | NIJ.ojp.gov

BYTE 35

Analyzing Internal 

Conditions

A nalyzing conditions inside a law enforcement agency contributes to identifying and 

diagnosing problems in the same way that crime analysis and traffic analysis help 

diagnose problems in the community. When left unattended, internal problems can 

negatively affect employee behavior and prevent organizational systems from performing 

as well as they should. Analyzing internal conditions — sometimes referred to as policy 

analysis, administrative analysis, or management analysis — is a necessary component 

of evidence-based police administration, the natural corollary of evidence-based policing. 

Recruitment and selection provide a good example. Many police agencies are currently 

unable to fill existing sworn officer positions, and in addition their ranks are not as diverse 

as the communities they serve. Although in some respects this is a national problem, not 

all agencies experience it to the same degree or for the same reasons. Most agencies 

have data from monitoring their situation, but analysis needs to go a few steps farther to 

figure out just where the problems are, and what might be causing them:

1. Recruitment — If the number of applicants has decreased over the years, it may 

be that agency marketing/advertising is not reaching or attracting potential recruits, 

the application process is too lengthy or cumbersome, or salary and benefits are 

not competitive. If applicant diversity is not sufficient, it may be that the agency’s 

prevailing image is not one of inclusion and fairness, or that recruiting is not conveying 

messages that resonate with all kinds of potential applicants.

2. Selection — It is possible that the number and diversity of initial applicants are 

sufficient, but the selection process is too slow, too restrictive, or has disparate 

impact. Analysis should look at each step in the selection process (e.g., written test, 

physical fitness test, interview, background check) to determine where applicants drop 

out and to check for differential impact on candidates who are women or members 

of minority groups. Analysis by itself cannot determine whether 20 push-ups or a 

score of 70% on a knowledge test is the right standard, but it can draw attention to 

selection criteria that might deserve more careful consideration.

3. Training — Some agencies lose a substantial number of recruits during the police 

academy, whereas other agencies rarely lose any, and the same is true for field 

training. Analysis should look at the dropout and failure rates in the academy and in 

field training, and should try to figure out why potential career employees are lost at 

these stages, after they have already passed through several rigorous screening steps. 

This analysis should also check for differential impact during training, especially on 

women recruits, since that is a common occurrence.
SUGGESTED

READING

Guilfoyle, S. 2013. Intelligent 

policing: How systems thinking 

methods eclipse conventional 

management practice. Devon, 

UK: Triarchy Press.

Evidence-Based Policing in 45 Small Bytes 87

4. Retention — When an agency has trouble reaching its authorized strength, 

sometimes the cause is more related to high turnover than weak recruiting, that 

is, people are leaving faster than they can be replaced. Analysis should track the 

agency’s turnover rate and seek explanations whenever employees leave short of 

retirement. Some degree of turnover is inevitable, of course, but a high rate can 

indicate that the agency hasn’t hired the right people in the first place, or that good 

employees aren’t satisfied with the agency for some reason. Analysis should try to 

figure that out, as well as watch carefully for disparity in turnover, which can indicate 

that the organization isn’t as welcoming and inclusive as it should be.

Numerous other internal conditions should be subject to routine monitoring, with deeper 

analysis undertaken when issues and problems are detected. Officer safety and wellness 

is a prime example. Data on officer injuries and sick leave should be carefully tracked 

along with hours worked per day and per week, and employee surveys can provide 

data on exercise, sleep habits, stress, and work-life balance. Analysis can then look 

for patterns and trends, such as an increase in preventable accidents or high levels of 

stress and burnout. It might also be the case that accidents are more common during 

some shifts than others, or that burnout varies with years of experience or particular 

assignments. Detecting patterns like these could help the agency target its responses to 

keep employees healthy and safe.

An important component of internal conditions is employee attitudes and beliefs. Surveys 

are quite valuable for discovering whether officers and civilian employees think their 

supervisor treats them fairly, their training has prepared them adequately, the disciplinary 

system is fair, their input is respected when decisions are made, the agency is headed in 

the right direction, and so on. When data like these are regularly collected, analysis can 

compare results to benchmarks to help judge whether responses are typical or unusual36

as well as looking for patterns, such as which types of employees don’t believe that their 

input is respected. This would also be a situation where analysis could go a step beyond 

the survey data by interviewing individuals or groups to explore in more detail any issues 

or problems that surface in the data.

Officers’ Attitudes and Beliefs

“These survey responses [from over 13,000 sworn officers in 89 agencies] show that the attitudes, 

beliefs, and perspectives of most police are relatively positive and favorable. Their occupational outlooks 

vary widely and are certainly not mainly negative or problematic. A majority of officers looks favorably 

on the public, supports community policing, and gives their immediate supervisor high marks. Police 

views are somewhat more mixed toward solidarity, misconduct, and toughness, some of which is 

probably reflective of the ambivalence and ambiguity inherent in the role of the police. Officers’ most 

widely held negative views are toward top management and administration. A strong theme is that good 

work is not recognized or rewarded nor is poor work penalized, and only a small minority of officers is 

very supportive of the direction being taken by top management.”

Source: Cordner, G. 2017. “Police culture: Individual and organizational differences in police officer perspectives.” Policing: An 

International Journal 40 no. 1: 11-25. https://www.emerald.com/insight/content/doi/10.1108/PIJPSM-07-2016-0116/full/html. 

36 The National Police Foundation administers the National Law Enforcement Applied Research & Data Platform, which 

provides surveys and results at no cost. See https://www.nationallawenforcementplatform.org. 
88 National Institute of Justice | NIJ.ojp.gov

BYTE 36

Analyzing Performance

A nother important analytical focus is on performance. The task here is to look 

carefully at performance data in order to identify any slippage or weaknesses, and 

then to examine those situations closely to try to figure out what the problems are 

and what is causing them. This approach applies to performance by individuals, units, 

programs, and the agency as a whole.

As an example, current year data might show an agency that one of its property crime 

detectives has a much lower clearance rate on assigned cases than the other detectives 

in the unit. A first step in an analysis would be to look at all the detectives’ caseloads 

to make sure they are really comparable; some of the detectives might be getting 

particularly lucky or unlucky with the number or types of cases assigned to them. One 

might have gotten all the shoplifting cases, which usually aren’t reported unless the 

thief is caught in the act, automatically producing a high clearance rate without any 

detective effort. Another might have drawn all the burglaries, which typically have a very 

low clearance rate since they aren’t discovered by victims until well after the fact. This 

is another good illustration that analysis should break down overly broad categories so 

as not to mix apples and oranges — the category “property crime” includes a range of 

offenses with differing degrees of difficulty when it comes to investigating and solving 

them. Any examination of performance data needs to carefully take such differences 

into account.

Continuing with the example, besides checking to make sure that individual caseloads 

really are comparable, analysis would want to look at previous years to see if the 

detective’s performance during the current year is an anomaly or part of a longer-term 

trend. If the low clearance rate isn’t “explained away” by bad luck and especially if it 

follows a trend, then the challenge would be to figure out what is causing the problem. 

In this scenario, the answer might be in data, if case records show that a low-performing 

detective rarely canvasses for additional witnesses, checks for surveillance video, 

seeks information from patrol officers, or takes other actions known to be effective in 

producing relevant information for solving crimes.37 More likely, perhaps, insights from 

the detective’s supervisor would be needed to explore reasons for the shortcomings 

in performance. 

37 Eck, J.E. 1983. Solving crimes: The investigation of burglary and robbery. Washington, DC: Police Executive 

Research Forum. NCJ 090569. https://www.ncjrs.gov/pdffiles1/Digitization/90569NCJRS.pdf. 
SUGGESTED

READING

Eterno, J.A., and E.B. 

Silverman. 2012. The crime 

numbers game: Management 

by manipulation. Advances 

in Police Theory and Practice 

Series. Boca Raton, FL: CRC 

Press.

Evidence-Based Policing in 45 Small Bytes 89

Analyzing performance at levels above the individual is particularly important for 

achieving and sustaining organizational effectiveness. Data might indicate that, for 

example, in one patrol district, officers are not attending as many neighborhood 

meetings as in other districts. Analysis would be directed at verifying this apparent 

problem (making sure it wasn’t just a documentation failure) and then figuring out the 

cause. It could be possible that some neighborhoods in this district don’t have active 

associations, or that officers are so much busier with calls for service and investigations 

that they don’t have time to attend meetings. It could also be the case that the district 

commander hasn’t communicated the importance of community engagement, or that 

direction and control are failing at some other point in the chain of command. 

Monitoring and analyzing performance by special units are just as essential as analyzing 

patrol and investigations. Information from citizen complaints or surveys might indicate 

a spike in callers dissatisfied with 911 operators, data might show an uptick in K-9 bites, 

injuries to people being held in detention might increase, or data might reveal a growing 

backlog of evidence in the crime lab. Any of those situations, and others like them, could 

represent serious performance problems or random fluctuations. Analyses would help 

in sorting them out, understanding them, and addressing those that merit some kind of 

remedial action.

One last point about analyzing performance: Organizations and analysts should be 

mindful that targets, objectives, and performance pressure can sometimes distort 

employee behavior in ways that are not intended. If it is known that district commanders 

are under pressure to produce arrests, citations, or stops, for example, their subordinates 

may reinforce the pressure down the line until patrol officers produce “the numbers” that 

relieve the pressure with a blitz of questionable enforcement. Similarly, if the pressure 

is on to reduce Part I crimes by 10% in the district, the end result may be “cooking the 

books” in an effort to show that the target was met. This phenomenon is universal, not 

limited to law enforcement agencies, and underscores two key principles: (1) Whenever 

possible, performance should be measured and analyzed in relation to quality, not just 

quantity, and (2) the usefulness of performance data depends on its quality, that is, its 

reliability and validity. Analysts should always be aware that people with something at 

stake are often tempted to manipulate data that bear on their performance. 

Perverse Effects of Performance Targets

“The reality is that when individuals are put under pressure to meet targets anything can (and does) 

happen. This does not mean that those who subvert the system are necessarily bad people; they 

are just trying to survive in a hostile environment — an environment where management inflicts 

unrealistic expectations upon them. I argue that targets inevitably promote perverse incentives and 

behaviors and the net result is that costs increase, morale is adversely affected, service delivery is 

suboptimised and the overall system is damaged. This is not a mere possibility. It is not a threat. It is 

a guarantee.”

Source: Guilfoyle, S. 2013. Intelligent policing: How systems thinking methods eclipse conventional management practice. 

Devon, UK: Triarchy Press, 143.

Evidence-Based Policing in 45 Small Bytes 91

SECTION 7:

Evaluating Practices and 

Testing Alternatives

E

arly in this guide (byte 2), four key components of an evidence-based policing 

(EBP) framework were identified — data, analysis, research, and evidence. So far, 

Sections 1 and 2 explained the EBP framework, emphasizing the importance of 

keeping the multidimensional bottom lines of policing front and center; Sections 3-5 

discussed the wide range of data an agency needs if it intends to be evidence-based; 

and Section 6 showed how analysis of all that data can help an agency identify gaps and 

problems and figure out why they are occurring. Next up is research.

As a reminder, the purpose of EBP is to make policing more effective. Research 

contributes to that purpose. This is the definition of EBP introduced earlier:

Using data, analysis, and research to complement experience and professional 

judgment in order to provide the best possible police service to the public. 

This definition says that law enforcement agencies and personnel should be informed 

by the best available scientific evidence as they go about identifying and understanding 

issues and problems, choosing responses, making decisions, setting policies, allocating 

resources, and enhancing employee well-being. Research doesn’t replace experience 

and professional judgment. The goal of research is to produce information that decisionmakers can use in conjunction with other sources of knowledge and wisdom. Also, the 

EBP framework supports applied research — research designed to produce practical 

information that helps an agency provide the best possible police service to the public.

The line between analysis and research is not clear-cut. Some of the types and examples 

of analysis discussed in Section 6 could be called research, and they certainly draw on 

research skills. In this section, however, the focus shifts from identifying and figuring out 

problems to determining whether responses to those problems are effective. This includes 

the programs, policies, and routine practices that the agency uses to try to reduce crime, 

hold offenders to account, reassure the public, and accomplish the other bottom lines of 

policing. It also includes the internal practices that the agency uses to meet the needs of 

employees and develop the capacity for quality performance. Research, in other words, is 

aimed at figuring out what’s working, and what’s not, throughout the organization.

One logical distinction is between the agency’s current practices and any new practices 

that it might be considering. In the case of current practices, what is needed is evaluation 

research. An agency should regularly evaluate its programs, policies, and other practices 

to make sure they are accomplishing the ends that are expected of them. This is very 
SUGGESTED

READING

Cockbain, E., and J. Knutsson, 

eds. 2015. Applied police 

research: Challenges and 

opportunities. New York: 

Routledge.

92 National Institute of Justice | NIJ.ojp.gov

important, since lots of things change over time, including personnel and conditions both 

inside the organization and in the community. A practice that made sense five or 10 years 

ago, and that may have been effective in the past, may or may not be effective today. Just 

assuming that it still works is a big mistake.

An equally important type of research involves testing new practices when they are 

adopted. When an agency decides to implement a new program, policy, or other practice, 

it is rational and wise to carefully study its impact to see if it actually has the outcomes 

that were expected of it. When this research is done right from the outset, as it should be, 

then the new practice can be fine-tuned based on feedback, increasing its effectiveness. 

And if it’s just not working at all, it can be called off or replaced with something else. In 

fact, the smartest way to implement new practices is to take this kind of testing approach 

by saying: “We think this new practice is the way to go, so we’re going to try it out. We’ll 

test it to see if it works as well as we think it will. If it doesn’t, we’ll try something else.”

Techniques for conducting these two categories of research activity — evaluating current 

practices and testing alternatives — are largely the same. One difference might be that 

the opportunity to use experimental methods is more likely when testing something new; 

alternative practices are often tried out as pilot studies anyway, making it easier to utilize 

comparison or control groups. Doing an experiment to evaluate a current practice would 

generally require ceasing the practice in some locations or for some people, which might 

be difficult to accept without an alternative to replace it. That said, the landmark Kansas 

City patrol study did just that, eliminating motorized preventive patrol in five beats for a 

whole year in an effort to determine whether that traditional practice was effective.38 A bit 

more about the Kansas City study will be mentioned shortly.

The next few bytes go into more detail about evaluating current practices and testing 

alternatives.

Why Evaluate and Test

“Taken for granted policies and practices, which are simply reproduced with no authority other 

than tradition or ideology, need to be tested empirically ... established practice is no guarantee 

of effectiveness. Indeed, counterproductive practices can survive in the absence of empirical test. 

Science itself is marked by organized skepticism, which means that scientists are perpetually 

open to doubt, to the possibility that they are mistaken. Even though in practical terms this might 

risk paralysis from uncertainty, it provides a healthy corrective to complacency. In a disciplined 

organization in which there is a strong can-do attitude, such as the police, it may be especially 

difficult to make routine that critical skeptical attitude which is the hallmark of science and which can 

be crucial to the early identification of weaknesses in working theories. Yet there are senior police 

officers who do, indeed, encourage their staff to raise doubts about standard working practices.”

Source: Tilley, N., and G. Laycock. 2017. “The why, what, when and how of evidence-based policing.” In J. Knutsson and L. 

Tompson, eds., Advances in evidence-based policing. London: Routledge, 20.

38 Kelling, G.L., T. Pate, D. Dieckman, and C.E. Brown. 1974. The Kansas City preventive patrol experiment: A summary 

report. Washington, DC: Police Foundation. https://www.policefoundation.org/wp-content/uploads/2015/07/Kelling-etal.-1974-THE-KANSAS-CITY-PREVENTIVE-PATROL-EXPERIMENT.pdf. 
Evidence-Based Policing in 45 Small Bytes 93

BYTE 37

Process and Outcome 

Assessment

Whether evaluating current practices or testing new ones, it is important to look 

carefully at both process and outcomes. On the surface, the main question 

seems quite simple: Does practice A lead to desired outcome B? Assessing a 

practice is not quite that simple, however. 

For starters, the agency needs to know for sure what the practice in question really 

is. Programs, policies, strategies, and tactics are often implemented differently than 

planned, and they often evolve over time. Also, they may not be implemented the same 

way in different parts of the organization. One of the first steps in a process assessment 

is documenting what the practice is “in the real world,” which is sometimes not what 

it looks like on paper or what the chief or sheriff thinks it is. Why is this so important? 

Because later, when the outcomes of the practice are identified, the agency will need to 

know what the practice actually was. A bad decision could be made if the practice is just 

assumed to have been what the original plan said it should be. For example, a common 

evaluation finding is “no effects.” In that situation, it is tempting to conclude that the 

practice didn’t work, but often the full story is that it was never implemented correctly.

Another aspect of process evaluation is basically capturing the story. This includes 

finding out if the practice was easy or difficult to implement, what challenges were 

encountered, how the challenges were overcome (if they were), what changes were made 

over time (if any) and why, what the people directly involved think should be changed (if 

anything) to make the practice work better, and so forth. The setting and context should 

also be identified; they might have a bearing on results. This might include the level of 

skills and experience of the staff involved, whether the problems addressed were routine 

or unusual, or any other features of the situation that might have contributed to success 

or failure. Ideally, the process evaluation should help fill in the statement, “The practice 

did (or did not) work well because ... .”

Some of the information needed for process assessment might come from routine 

agency data. If an agency is using hot spots patrol, for example, GPS data from the 

computer-aided dispatching system could be used to document the number of times 

that officers visited the hot spots and how much time they spent there. However, if the 
94 National Institute of Justice | NIJ.ojp.gov

tactic called for officers to get out of their patrol cars and walk around in the hot spots, 

observations and interviews might be needed to determine whether they did that, what 

other actions they took while sitting or walking in the hot spots, and the reasons why they 

did or didn’t implement the tactic as instructed. Observations might also help identify 

characteristics of hot spots that seem to draw more or less enthusiasm from officers. 

Combining quantitative data with qualitative observations and interviews is what’s known 

as mixed methods research. It is important to recognize that neither quantitative nor 

qualitative research is inherently better. The choice of which approach to take depends 

on the situation, the purpose of the research, and the questions that need answering. 

Particularly for process assessment, that is, determining just what was implemented and 

why, a mixed methods approach is often the best.

Assessments also look at outcomes. Any program, policy, or other practice is expected 

to achieve something — reduced crime, increased public trust, fewer officer injuries, 

improved morale, and so on. An assessment tries to determine if the desired outcome 

was achieved. At a minimum, this usually depends on a baseline measurement before 

the practice is implemented, and then a follow-up measurement some time later. For an 

ongoing practice, assessment can check to see if the desired outcome is continuing to 

get better, remaining at an acceptable level, or declining. 

One important consideration for outcome assessments in policing is that all the bottomline outcomes are applicable. Hot spots patrol may be aimed primarily at reducing crime, 

for example, but its impact on maintaining safety and order, reassuring the public, using 

force and authority fairly, and other bottom-line outcomes (including police legitimacy) 

should be assessed as well. Looking at the whole range of bottom-line outcomes is 

crucial, since it is common for a policing practice to affect more than just one outcome, 

and all the outcomes are important.

A related consideration is to anticipate all the likely consequences of a practice and 

then measure whether they occur, as opposed to just measuring the one expected 

outcome. For example, implementing a crime prevention program based on educating 

the public about risks and threats could have the unintended result of increasing fear of 

crime. Implementing a location-based crime reduction program could displace crimes 

to other locations. Implementing more realistic self-defense training during the police 

academy, in order to give new officers more confidence about their physical skills, could 

result in more injuries to recruits. Hopefully, none of these side effects or unintended 

consequences would come to pass, but ones that can logically be anticipated should be 

measured, just in case.

More details and examples are provided in the next few bytes.
SUGGESTED

READING

Eck, J.E. 2002. Assessing 

responses to problems: An 

introductory guide for police 

problem-solvers. Tool Guide 

No. 1. Washington, DC: U.S. 

Department of Justice, Office 

of Community Oriented Policing 

Services. https://cops.usdoj.gov/

RIC/Publications/cops-p034-

pub.pdf.

Evidence-Based Policing in 45 Small Bytes 95

Research Methods in Evidence-Based Policing

“Conducting an experiment is not an end goal by itself; research questions ought to be answered 

with the appropriate research methods, and not the other way around. Over a century of ‘researchmethods theories’ have been developed, and science has a rather robust layout for marrying 

research questions and the ways in which these queries can be answered. The more pertinent 

definition of EBP should therefore be using the most appropriate research design to collect evidence 

that will guide practitioners and continually evaluate practice.”

Source: Ariel, B. 2019. “‘Not all evidence is created equal’: On the importance of matching research questions with research methods 

in evidence based policing.” In R.J. Mitchell and L. Huey, eds., Evidence based policing: An introduction. Bristol, UK: Policy Press, 64.
96 National Institute of Justice | NIJ.ojp.gov

BYTE 38

Evaluating Current 

Practices

T

he landmark Kansas City patrol study completed in 1973 was a great example of 

evaluating a current practice. Members of the police department were the ones 

who suggested doing the study, based on their realization that some officers in the 

agency thought routine motorized patrol was absolutely essential for controlling crime 

and reassuring the public, while others thought of patrolling as “down time” — what they 

did while waiting for something to happen. It occurred to them that a study might help 

determine how effective the practice really was. The police department then got outside 

assistance to conduct the study, which produced valuable information for the agency and 

the entire police field.39

A more recent example comes from Austin, Texas, where the impetus to evaluate 

a current practice came from outside the agency. In that city, political leaders and 

community activists became critical of a longstanding juvenile curfew ordinance; the data 

suggested that it was applied disproportionately against minority youth. The police chief 

was able to forestall a rash political decision by promising to evaluate the department’s 

use of the ordinance and then report back. In this case, his staff was first able to locate 

previous research completed in other jurisdictions; those studies had not found any 

beneficial impact of juvenile curfews on crime or youth victimization. Staff also reviewed 

Austin’s own past use of its ordinance, finding that it was not being used as often as 

they thought, and when it was used there were other legal tools that would have worked 

just as well. This evaluation showed that the city’s juvenile curfew ordinance was neither 

effective nor an essential tool in the police arsenal. Based on the evaluation, the chief 

reported that the police department had no objection to the ordinance’s repeal.40

As these two examples show, recognition that a current practice ought to be evaluated 

can come from within the law enforcement agency or from outside the organization. 

In some cases, there may be a relevant body of existing research to draw on, but not 

always. In some cases, a rigorous evaluation of the current practice may be called for, 

even potentially a full-blown experiment, while in other cases a review of records and 

data may be sufficient. And, in some cases, the agency may need a research partner to 

guide the evaluation, but sometimes an in-house evaluation is sufficient.

39 Kelling, G.L., T. Pate, D. Dieckman, and C.E. Brown. 1974. The Kansas City preventive patrol experiment: A summary 

report. Washington, DC: Police Foundation. https://www.policefoundation.org/wp-content/uploads/2015/07/Kelling-etal.-1974-THE-KANSAS-CITY-PREVENTIVE-PATROL-EXPERIMENT.pdf. 

40 Roman, I. 2018. “The curfew myth: How a ’90s panic spawned an anti-crime measure that doesn’t make you safer.” 

The Marshall Project (July 31). https://www.themarshallproject.org/2018/07/31/the-curfew-myth. 
Evidence-Based Policing in 45 Small Bytes 97

At any given time, a police agency has many programs, policies, and other practices in 

use. A logical approach to evaluating them is to prioritize those that are presumed to 

be contributing to bottom-line outcomes, along with those that are most costly. On the 

first point, an agency’s practices aimed at reducing serious crime, holding offenders to 

account, maintaining safety and order, reassuring the public, providing quality services, 

and using force and authority fairly and effectively should all be reviewed periodically 

because these are the key policing outcomes the community counts on. For example, if 

the agency encourages people to report certain offenses online, it would be important 

to find out if that method of service delivery is satisfactory to victims, and also whether 

it produces the information needed to guide crime reduction and investigation initiatives. 

If evaluation reveals that the practice is not doing as well as needed on any of those 

dimensions, then some kind of adjustment should be considered. Another example could 

be officers assigned to schools. That kind of program should be evaluated regularly 

across a wide range of bottom-line outcomes, both to make sure that officers are 

performing as expected and to see if the results are positive.

In regard to cost, police training comes to mind as an activity that is quite expensive, 

yet rarely subject to serious evaluation. The financial cost of training includes not only 

trainers, facilities, and supplies but also the salaries of recruits and officers while they 

are attending training and therefore not filling assigned positions. Especially since they 

are so costly, agencies should carefully evaluate all their training programs to see how 

well the attendees are acquiring the knowledge and skills that the courses are supposed 

to teach. Unless the results are overwhelmingly positive, part of the evaluation should 

include observations and interviews aimed at identifying particular course segments and 

teaching/learning methods that are working well or not so well. Importantly, evaluation of 

training should also include discovering the impact on officers’ performance once they 

return to work — not just what they know and can do at the end of the training course 

but also whether their subsequent performance improves. If it doesn’t, the training might 

have been a nice experience, but it wasn’t effective.
SUGGESTED

READING

Hoover, L.T., ed. 1998. 

Police program evaluation.

Washington, DC: Police 

Executive Research Forum.

98 National Institute of Justice | NIJ.ojp.gov

Critical Incident Stress Debriefing

A current practice in many agencies is critical incident stress debriefing (CISD), in which a trained 

therapist, following a specific protocol, “conducts a debriefing session either individually or with 

a group of individuals who have experienced a critical incident.” The session, which is conducted 

within 1-2 days of the event, is designed to get those involved to talk about and face what they 

experienced.

Unfortunately, independent evaluations have not found that CISD is beneficial and, in some cases, it 

may even be harmful. Based on scientific evidence accumulated over the past 20 years, numerous 

military and first-responder organizations around the world have discontinued and/or revised their 

use of this specific practice for relieving critical incident stress. 

The lesson here is that agencies need to carefully evaluate their current practices, even ones that 

have the reputation of a best practice based on the fact that they are widely used. Also, an important 

element of evaluating current practices is taking advantage of relevant studies already conducted 

elsewhere. It isn’t always necessary to reinvent the wheel.

Source: Adapted from Mitchell, R. 2018. “The harmful effects of critical incident stress debriefing (CISD): Why police 

departments should stay up to date on evidence-based practices.” Washington, DC: American Society of Evidence-Based 

Policing. https://www.americansebp.org/the-harmful-effects-of-critical-incident-stress-debriefing-cisd-why-policedepartments-should-stay-up-to-date-on-evidence-based-practices. 
Evidence-Based Policing in 45 Small Bytes 99

BYTE 39

Testing New Practices

When a law enforcement agency decides to implement a new program, policy, or 

other practice, the decision is based on an expectation that the new practice 

will be beneficial. If the practice is replacing something else, the expectation 

is that it will work better. If it is simply a brand new effort, the expectation is that it will 

have positive results. The logical and rational thing to do is to evaluate the new practice 

when it is implemented to determine if it is as effective as expected. In addition, a realtime formative evaluation can provide quick feedback to help steer the new practice in a 

positive direction. Emphasizing improvement from the beginning is important, since not 

every new practice is perfect right from the start. 

An earlier example from Chula Vista, California, illustrates how to test a new alternative 

practice.41 The police department had carefully analyzed the domestic violence problem 

in its city and checked previous research for promising responses. When a new protocol 

was selected, it was implemented in one police district while a separate district served 

as the comparison area. The agency ran the pilot test for 18 months and found that 

domestic violence crimes and calls dropped 24% in the target district versus a slight 

uptick in the comparison district. The evaluation also showed that victim satisfaction 

was higher in the target district. Based on this test of the new practice, it was then 

implemented citywide.

Numerous law enforcement agencies have implemented body-worn cameras (BWC) in 

recent years and sought to evaluate their effects.42 This is an example of adopting a new 

technology, which in many cases permits a relatively straightforward evaluation. With 

BWC, however, implementation has turned out to be more complicated than expected, 

since it must consider when to turn on the cameras, when to turn them off, how long 

to store the video, and who gets to see the video. In addition, the presence of BWC 

might affect officer and/or citizen behavior, officer and/or citizen attitudes, complaints, 

internal investigations, and prosecutions (of either arrested citizens or police). Although 

evaluating this new technology has proven to be far more complex than expected, 

findings from evaluations have already been helpful to agencies when making decisions 

about whether to adopt the technology and, if it is adopted, how best to use it.

41 Chula Vista Police Department. 2018. “Reducing domestic violence in Chula Vista, CA.” https://popcenter.asu.edu/

sites/default/files/chula_vista_2018_pop_conference_presentation.pdf. 

 42 Lum, C., M. Stoltz, C.S. Koper, and J.A. Scherer. 2019. “Research on body-worn cameras: What we know, what we 

need to know.” Criminology & Public Policy 18 no. 1: 93-118. https://onlinelibrary.wiley.com/doi/abs/10.1111/1745-

9133.12412. 
100 National Institute of Justice | NIJ.ojp.gov

A major initiative in Baltimore County, Maryland, in the 1980s illustrates the value of 

feedback for improving a new practice after its initial implementation.43 Facing concerns 

about rising fear of crime, the county police department implemented a special citizenoriented police enforcement (COPE) unit of 45 sworn officers. During the unit’s first 

year of operation, COPE officers targeted various neighborhoods suspected of having 

an elevated fear of crime, using mainly saturation patrol tactics. Ongoing evaluation 

showed that COPE officers engaged in relatively little public contact during their patrols, 

which conflicted with available evidence that the “felt presence” of police was what best 

reassured citizens. In COPE’s second year, officers were instructed to increase their 

public contact, which they mainly accomplished by holding crime prevention meetings 

and conducting security surveys in target neighborhoods. Evaluation showed that these 

tactics were modestly more effective in reducing residents’ fear of crime but that they 

weren’t specifically tailored to whatever was actually causing citizen concerns in different 

neighborhoods. Based on that feedback, COPE officers shifted to a more problemoriented approach in their third year, first diagnosing the specific causes of fear in target 

neighborhoods and then implementing tailored responses. The evaluation showed that 

this approach had a bigger impact on residents’ fear of crime than the earlier approaches 

of using saturation patrol and standard crime prevention techniques, and it was adopted 

as the COPE unit’s standard methodology from that point forward.

When testing new practices, experimental and quantitative methods are often employed, 

since there may be the opportunity to utilize comparison or control groups during 

initial pilot testing, and since there may be time to gather baseline data before the new 

practice is implemented. Using these methods is highly recommended because they add 

scientific credibility to findings about whatever impact the new practice seems to have. 

At the same time, though, qualitative information can be crucial for figuring out how 

and why things turn out the way they do when a new practice is implemented. For 

example, Chicago started a major community policing initiative in 1993 in five police 

districts and then expanded the initiative citywide in 1995. Even though the effort had 

its ups and downs over the course of 10-15 years, the impact on crime, disorder, fear 

of crime, and police-community relations was positive. The evaluation documented 

these impacts with a massive amount of survey and official data, while also gathering 

observational and interview data from hundreds of beat-level community meetings at 

which officers and residents worked to identify and target local problems.44 That kind of 

qualitative information was very useful for gauging the actual level and nature of policecitizen interaction and community engagement that took place across a diverse array of 

neighborhoods, which in turn helped with interpretation of the “hard data.”

43 Cordner, G. 1988. “A problem-oriented approach to community oriented policing.” In J.R. Greene and S.D. 

Mastrofski, eds., Community policing: Rhetoric or reality. New York: Praeger, 135-152.

44 Skogan, W.G. 2006. Police and community in Chicago: A tale of three cities. Oxford: Oxford University Press.
SUGGESTED

READING

Skogan, W.G. 2006. Police and 

community in Chicago: A tale 

of three cities. Oxford: Oxford 

University Press.

Evidence-Based Policing in 45 Small Bytes 101

Targeting, Testing, and Tracking

1. “Police should conduct and apply good research to selectively target their scarce resources on 

predictable concentrations of harm from crime and disorder (a ‘power few’).”

2. “Once they choose their high-priority targets, police should use tests of police methods to help 

choose what works best to reduce harm.”

3. “Once police agencies use research to target their tested practices, they should generate and use 

internal evidence to track the daily delivery and effects of those practices, including the publicly 

perceived legitimacy of policing.”

Source: Sherman, L.W. 2019. “Targeting, testing, and tracking: The Cambridge Assignment Management system of evidence 

based police assignment.” In R.J. Mitchell and L. Huey, eds., Evidence based policing: An introduction. Bristol, UK: Policy Press, 20.
102 National Institute of Justice | NIJ.ojp.gov

BYTE 40

Experiments and 

Quasi-Experiments

E

xperiments are considered the “gold standard” for evaluating and testing the 

impact of programs, policies, and other practices. Sometimes called a randomized 

controlled trial (RCT), an experiment has two main features that set it apart from 

other evaluation methods: a control group and randomization. The first feature means 

that while one group of subjects (such as people or places) gets the “treatment,” which 

is the practice being tested, another group doesn’t get it and so serves as a comparison. 

Randomization means that the subjects are randomly assigned to either the treatment or 

control group, which prevents bias from influencing who gets assigned to which group.

One of the better-known applications of the experimental method is for testing new 

drugs. Among a group of subjects, half are randomly selected to receive the drug, while 

the other half get a placebo (sometimes called a sugar pill) that looks just like the real 

thing. After an appropriate amount of time, the subjects are checked to see whether 

those who got the new drug have been affected any differently from those who got the 

placebo. If the answer is yes, it can be concluded that it was the drug that made the 

difference, and not some other factor.

Experiments are the gold standard of evaluation because they can demonstrate causation. 

In the drug trial example, if the treatment group got better but the control group didn’t, 

it is plausible to claim that the drug caused the improved health in the treatment group. 

Most other methods of evaluating the impact of programs and practices fall short in this 

regard — they may be able to document that things got better (e.g., patients’ health, crime, 

public trust), but they cannot support a scientific claim that it was the particular treatment 

or practice that caused the improvement. In nonexperimental studies, the possibility that 

something else caused an observed change can’t be ruled out.

Another way of explaining the advantage of experiments is with the principle that 

correlation doesn’t prove causation. Ice cream consumption and drowning both go up 

in the summer months, but that doesn’t prove that ice cream causes drowning. In the 

police world, accreditation provides a similar example. Numerous studies have found 

that agency accreditation is linked (correlated) with desirable outcomes. One explanation 

could be that accreditation causes law enforcement agencies to improve, but another 

possibility is that agencies that are already “better” are most likely to pursue and achieve 

accreditation. Absent an experiment or some other type of rigorous study, there isn’t 

a strong scientific basis for choosing between the two possible explanations. Again, 

correlation doesn’t prove causation.
Evidence-Based Policing in 45 Small Bytes 103

Experiments might seem difficult and impractical in the real world of policing, but they are 

more common than most people realize. One comprehensive search located 122 police 

RCTs from 1970 to 2015, with the pace of experimentation picking up substantially in 

recent years.45 Some experiments in policing have been major undertakings, such as the 

Kansas City Preventive Patrol study that covered 15 beats for an entire year. Others are 

more short term and focused. Vallejo, California, ran a 90-day trial with three automatic 

license-plate readers, randomly setting whether the technology alerted officers or not 

in order to test how it affected officer behavior and productivity.46 The same agency did 

a 34-day test with two night-shift units that patrolled in a commercial shopping district; 

their Code-2 roof lights were randomly set to be either on or off, to see if the lights had 

an impact on auto burglaries and auto thefts.47 The National Police Foundation ran a 

six-month experiment that included 226 patrol officers from two departments who were 

randomly assigned to eight-, 10-, or 12-hour shifts to test the effects of shift length on 

performance, safety, health, stress, sleep, fatigue, and alertness.48

Besides the practical challenge of conducting an experiment in the real world, one 

common concern is ethical — Is it fair to make “guinea pigs” out of police officers or 

community residents by randomly deciding who will and who won’t get some new 

program or practice? The ethics of experimentation with human subjects is a very 

important consideration, and strict criteria have to be met for an RCT to be approved. 

In general, though, the rationale is that (1) whether the new practice will have positive 

results is not yet known, so no one is being denied a benefit; and (2) an experiment is 

the only way to determine whether there are positive (or negative) results from the new 

practice, which is essential to learn so that everyone may eventually benefit (or avoid 

being harmed).

Needless to say, not all evaluation studies are experiments. The label “quasi-experiment” 

applies to evaluations that don’t meet the RCT criteria but that do take meaningful 

steps to minimize “threats to validity” (alternative explanations for the study’s results). 

One common variant is the use of a nonrandom comparison group. For example, a 

police academy might try one method of de-escalation training with a cohort of officers 

attending in-service training, and a different method with a second cohort the following 

week (i.e., the subjects are not randomly assigned officers, but whichever officers 

happen to be signed up each week). If there was a difference in outcomes between the 

two cohorts, it would be tempting to conclude that the method of training caused the 

45 Neyroud, P.W. 2017. Learning to field test in policing: Using an analysis of completed randomised controlled trials 

involving the police to develop a grounded theory on the factors contributing to high levels of treatment integrity 

in police field experiments. Cambridge, UK: Cambridge University. https://www.repository.cam.ac.uk/bitstream/

handle/1810/268177/Neyroud-2017-PhD.pdf. 

46 Potts, J. 2017. Interview by BetaGov (New York University). http://www.betagov.org/blog/uncategorized/betagovspotlight-jason-potts. 

47 Potts, J. 2019. “Police vehicle lights: Reducing crime through increased police visibility.” New York: New York University, 

The Marron Institute of Urban Management, BetaGov. http://www.betagov.org/completed-trials/Police-Vehicle-Lights.pdf. 

48 Amendola, K.L., D. Weisburd, E.E. Hamilton, G. Jones, and M. Slipka. 2011. The shift length experiment: What we 

know about 8-, 10-, and 12-hour shifts in policing. Washington, DC: Police Foundation. https://www.policefoundation.

org/wp-content/uploads/2015/12/Shift-Length-Experiment-Practitioner-Guide.pdf. 
SUGGESTED

READING

Campbell, D.T., and J.C. 

Stanley. 1963. Experimental 

and quasi-experimental 

designs for research. Boston: 

Houghton Mifflin.

104 National Institute of Justice | NIJ.ojp.gov

differing results, but it would be hard to rule out the possibility that the two groups of 

officers differed from each other in the first place. If that possibility had been anticipated, 

baseline data might have been collected to help determine if the two groups really were 

comparable prior to the training. Another way to strengthen the quasi-experiment would 

be to run it with multiple groups, rather than just two. In the end, however, the scientific 

basis of the claim that “A caused B” is almost always stronger with an experiment.

The best advice when evaluating programs and practices is, not surprisingly, to use 

the most rigorous design possible within the practical constraints of the situation. The 

objective is always to determine the outcomes of what is being evaluated — and whether 

those outcomes were caused by the program or practice — with as much confidence 

and credibility as conditions permit, so that decision-makers can use the results to make 

informed decisions that contribute to agency effectiveness.

Internal Validity

“We assess internal validity of a study’s findings by asking what the possible causes of the outcome 

are. Typically, in an evaluation, we are interested in determining if a single intervention (e.g., 

additional lighting to a crime hot spot) had an impact on an outcome (e.g., crime). If the finding is 

that the intervention did change the outcome, we ask what else could have done so. There are often 

several: for example, random variation caused the outcome, environmental factors unconnected with 

the intervention caused the outcome, or even the outcome caused the intervention. If the study is 

able to eliminate all rival explanations, then we are entitled to believe the intervention caused the 

change. If the study cannot eliminate any alternative explanations, then its findings have no internal 

validity. In general, the more alternatives the study can rule out, the more internal validity for the 

study’s findings.”

Source: Eck, J. 2017. “Some solutions to the evidence-based crime prevention problem.” In J. Knutsson and L. Tompson, eds., 

Advances in evidence-based policing. London: Routledge, 49.
Evidence-Based Policing in 45 Small Bytes 105

BYTE 41

Nonexperimental 

Evaluations

Most evaluations of programs and practices, including those done in the policing 

field, are not experiments, and many are not even quasi-experiments. This fact 

limits how strongly an agency can claim that what it did caused some outcome 

(or failed to cause it). This is a significant limitation, since it makes it hard for agency 

leaders to know whether the practice should be continued and/or expanded, and it 

leaves other agencies unsure about whether to adopt the practice. In terms of evidencebased policing, the absence of experimental evaluations limits the development of 

evidence about what works.

However, evidence is a matter of degrees, not all or nothing. With a weaker design, 

the conclusion is not likely to be “we have no idea” but rather, “things got better, and 

we think it was due to what we did.” As a practical matter, documenting that better 

outcomes were achieved is generally an agency’s top priority. Knowing with confidence 

what might work the next time (i.e., if causation was established) is important, too, but in 

the meantime, positive results are positive results.

Whenever possible, an evaluation should at least measure before and after the practice 

is introduced. That requires a bit of planning and forethought: to identify in advance the 

desired/expected outcomes of the practice, as well as any likely side effects, and then 

measure those things before the practice is implemented. The investment in establishing 

these baseline measures is a wise one because it sets up the ability to measure the same 

outcomes later to document whether anything changed. 

Without a baseline, an evaluation can usually only determine whether people think 

the practice had a beneficial effect. The thoughts and beliefs of people involved 

in an initiative are certainly relevant, especially their insights about what was really 

implemented, what hurdles and challenges were encountered, and what might be done 

differently to improve effectiveness. But in regard to a practice’s impact on outcomes 

(reducing crime, improving public trust, making officers safer), the opinions of people 

involved in the effort are far less credible than a carefully measured comparison of before 

and after the practice’s implementation.
106 National Institute of Justice | NIJ.ojp.gov

In addition to measuring before and after, any evaluation, whether experimental or not, 

should include a careful look at the process involved, not just the impact. This entails 

monitoring the implementation through the use of performance data, observations, 

and interviews to capture the story of what took place. This is so important because 

programs and practices are often changed during implementation, and sometimes never 

implemented at all. Unless the evaluation captures information about what was actually 

implemented, knowing whether outcomes got better or worse will still leave decisionmakers wondering whether to continue or discontinue the practice. 

As one simple example of the importance of process monitoring, a field evaluation of 

the effectiveness of a new police baton wouldn’t be very useful if it failed to notice that 

officers never carried the equipment when they exited their vehicles. If officers said they 

liked the batons and there were no reports of misuse or breakage, it might seem like a 

case of positive outcomes, but the real story would have been that the equipment was 

never put into use. Similarly, an evaluation of a community policing initiative wouldn’t be 

complete if it didn’t take a close look at just how much citizen interaction and community 

engagement took place. If the officers involved mainly stayed in the office or in their 

patrol cars, a finding of minimal impact on public reassurance might be more indicative 

of implementation failure rather than evidence that community policing was ineffective.

The least desirable evaluation design is the ex post facto case study. This type of 

evaluation lacks both a baseline and real-time collection of process information while the 

practice is being implemented. Sometimes, baseline data may be available retroactively 

through official data such as reported crime figures, but in other cases it isn’t possible to 

go back in time and take baseline measurements of outcomes that might be important, 

such as fear of crime, public trust, or officer morale. Without that baseline, the evaluation 

is limited to people’s recollections, which may not be accurate and may easily be swayed 

by the fact that a practice is being evaluated. In addition, information about what was 

actually implemented and the challenges that were encountered may only be available 

through the memory of participants, again raising issues of accuracy and potential bias. 

Participants might paint an overly positive or negative picture, depending on whether 

they liked the program or practice. Without any independent observations of the 

implementation in action, an ex post facto evaluation could be unreasonably swayed by 

participants’ self-serving comments about what took place.

As noted, evaluating is not an all-or-nothing exercise. Different evaluation methods have 

their strengths and weaknesses, and their findings should be weighed accordingly. As 

a general rule, current practices and new alternatives should be tested as rigorously 

and systematically as possible because finding out what works best, and identifying 

shortcomings that might be improved, is the path to more effective policing.
SUGGESTED

READING

Rossi, P.H., M.W. Lipsey, and 

H.E. Freeman. 2003. Evaluation: 

A systematic approach. 

Seventh edition. Thousand 

Oaks, CA: Sage.

Evidence-Based Policing in 45 Small Bytes 107

Small-Scale Evaluation

Sometimes, a practice being evaluated is a relatively small-scale effort aimed at solving a specific 

problem or achieving a small improvement in performance. In such cases, a nonexperimental 

evaluation may be quite satisfactory. Many examples of this level of activity are found in problemoriented policing and situational crime prevention. When a police department tackles chronic crime 

and disorder at a budget motel, for instance, it is strongly interested in evidence about whether 

crime and disorder are reduced following their effort. If not, they need to try something else. Their 

interest in scientific proof that their responses caused the positive results is not as strong, and if they 

implemented three responses, they may not particularly care which of the three deserves the most 

credit. Although that kind of information could be useful for future problem solving, it is also expected 

that the circumstances will probably be different with any future chronic motel problem, so a tailormade response will be needed the next time anyway.

Source: Adapted from Eck, J.E. 2002. “Learning from experience in problem-oriented policing and situational prevention: 

The positive functions of weak evaluations and the negative functions of strong ones.” In N. Tilley, ed., Evaluation for crime 

prevention. Crime Prevention Studies Vol. 14. Monsey, NY: Criminal Justice Press, 93-117.

SUGGESTED

READING

Mitchell, R.J., and L. Huey, eds. 

2019. Evidence based policing: 

An introduction. Bristol, UK: 

Policy Press.

Evidence-Based Policing in 45 Small Bytes 109

SECTION 8:

Using Evidence

What ultimately matters is using the best available evidence. The purpose of 

data, analysis, evaluation, and research is to enhance situational awareness, 

identify and diagnose problems, and produce evidence about what works 

most effectively. All of that should have “a seat at the table.” Then, it is up to police 

practitioners, managers, and leaders to incorporate the evidence into their planning and 

decision-making.

It deserves to be reemphasized that data and analysis are key elements of the foundation 

for evidence-based policing. It makes no sense for an agency to adopt an evidencebased practice if that practice doesn’t address actual conditions and problems facing 

the agency. A police department doesn’t need hot spots patrol if it doesn’t have any 

crime hot spots or if its only serious crime problem is domestic violence. It doesn’t need 

a violent crime reduction program if it has little or no violent crime. Data and analysis 

are crucial for monitoring actual conditions, spotting trends, identifying problems, and 

figuring out what’s causing them.49 They can also help an agency avoid adopting the 

latest fad if it doesn’t address a problem that actually exists in the jurisdiction.

This final section focuses on using evidence, starting with two key questions: Where is 

evidence found, and how much weight should be given to it?

Tipping Point?

“Policing is on an evolutionary journey when it comes to embracing evidence. There are currently 

positive signals that there is movement forward toward science or evidence. Whether we are at a ‘tipping 

point’ — that point at which it requires less energy to go forward than to retreat backwards — is 

debatable. However, it is argued that, as with other fields such as medicine and engineering, which 

have embraced over time scientific methods and utilized research to guide and shape practice, 

policing will also continue to move with increased pace in this future scientific direction. There is 

positive movement in this direction and the strategies and signposts for success are becoming clear.”

Source: Martin, P. 2019. “Moving to the inevitability of evidence based policing.” In R.J. Mitchell and L. Huey, eds., Evidence 

based policing: An introduction. Bristol, UK: Policy Press, 212.

49 As mentioned earlier, this is just as applicable for small agencies as for large ones. The difference is that larger 

agencies have more to keep track of, and more data to sift through, to stay on top of things and spot trends and 

problems. Smaller agencies can often accomplish this informally, just because there is less to keep track of, but they 

have exactly the same need to be on top of things.
110 National Institute of Justice | NIJ.ojp.gov

BYTE 42

Finding and Weighing 

Evidence

T

he previous section emphasized that any law enforcement agency should test and 

evaluate both existing practices and new ones in order to develop evidence to 

guide its decision-making. An approach focused on the agency’s own practices 

needs to be combined with evidence derived from the rest of the policing universe — the 

18,000 or so U.S. law enforcement agencies, the thousands of other police agencies 

around the world, and the researchers who study policing.

This is easier said than done. Finding evidence about what’s known and what works 

in policing can be difficult. For one thing, the United States is a big country in an even 

bigger world. In addition, research results are typically written for an academic audience 

rather than for practitioners, and they are often published in academic journals that are 

not readily accessible and are typically behind paywalls. In other cases, findings are 

presented in internal agency reports that aren’t widely distributed or easily found.

Fortunately, government agencies and scholars have begun the task of gathering up 

and assessing relevant studies of policing practices. These efforts are relatively new and 

don’t yet cover every aspect of police effectiveness, but they are a start. One technique 

being used more and more often is the systematic review, which is a kind of extrathorough literature review — an exhaustive international search for all studies on a topic, 

strict criteria for judging which studies are scientifically credible, and a rigorous formal 

process for aggregating the findings from those studies that meet the criteria.50 When 

possible, a meta-analysis is also conducted to calculate a pooled estimate of effect size, 

which is the average impact that a particular practice has on a specific outcome, such as 

the average impact of hot spots patrol on crime in a targeted area.

One institution that sponsors systematic reviews covering various topics, including crime 

and policing, is the Campbell Collaboration.51 Another institution, the U.K. College of 

Policing (which is a professional body, not a degree-granting school in the American 

sense of the word college), offers an online What Works Centre that currently rates 

the effectiveness evidence for 57 different crime reduction practices.52 And here in the 

50 Neyroud, P. 2019. “Systematic reviews: ‘Better evidence for a better world.’” In R.J. Mitchell and L. Huey, eds., 

Evidence based policing: An introduction. Bristol, UK: Policy Press, 103-116.

51 See https://campbellcollaboration.org. 

52 See https://whatworks.college.police.uk/toolkit/Pages/Toolkit.aspx.
Evidence-Based Policing in 45 Small Bytes 111

United States, the National Institute of Justice (NIJ) sponsors CrimeSolutions.gov, a site 

that rates individual studies and meta-analyses as effective, promising, or no effects 

according to strict criteria.53 This NIJ site organizes its reviews into eight categories, 

including one for law enforcement research and another for crime prevention studies.

All three of these sources use scientific criteria when assessing evidence of impact, 

heavily favoring experimental over nonexperimental studies. An important feature of the 

U.K.’s What Works Centre is that it assesses the evidence pertaining to each practice 

on four additional dimensions — how the practice works (mechanism), how it is affected 

by context (moderators), what it takes to implement the practice, and what it costs. This 

supplemental information is included based on an understanding that police need to 

know more about a practice than just its projected impact when they are considering 

whether to adopt it, and when planning how to implement it successfully.54

A source of “what works” information that is organized differently is the Center for 

Problem-Oriented Policing. Whereas systematic reviews, the U.K. College of Policing’s 

What Works Centre, and NIJ’s CrimeSolutions.gov mainly focus on the effectiveness of 

police practices, the Center for Problem-Oriented Policing focuses primarily on specific 

problems. For example, its problem-oriented policing (POP) guide on gun violence among 

serious young offenders reviews various responses to that particular problem, including 

available evidence about what works best under different circumstances. Other POP 

guides identify the types of data that an agency should collect and analyze to diagnose 

its specific problem, since gun violence, burglary, drug dealing, and other problems may 

not have the same characteristics and patterns in every jurisdiction. There are currently 

73 of these specific POP guides posted on the site.55

Unfortunately, a shortcoming of all these sources of “what works” information is that they 

are mostly limited to crime reduction practices and problems. As a result, a police agency 

that wants to take an evidence-based approach to reducing crime has a fair amount 

of accessible evidence to draw from. But agencies that also want to adopt evidencebased practices related to policing’s other bottom lines (holding offenders to account, 

maintaining safety and order, reassuring the public, providing quality services, using force 

and authority fairly and effectively, using financial resources efficiently, building public 

trust, sustaining police legitimacy, and enhancing officer safety and well-being) have to 

dig a lot deeper into the worldwide reservoir of studies and will probably have to do their 

own assessments of what the research adds up to. 

There are a few exceptions to the mainly crime-focused nature of available effectiveness 

evidence. For example, the What Works Centre has assessments of red light cameras, 

speed cameras, and several measures aimed at reducing drunk driving, and there are 

53 See https://www.crimesolutions.gov. 

54 Bowers, K., L. Tompson, A. Sidebottom, K. Bullock, and S. Johnson. 2017. “Reviewing evidence for evidence-based 

policing.” In J. Knutsson and L. Tompson, eds., Advances in evidence-based policing. London: Routledge, 98-116.

55 See https://www.popcenter.org/problem-guides. 
SUGGESTED

READING

Kugley, S., A. Wade, J. Thomas, 

Q. Mahood, A.-M.K. Jørgensen, 

K. Hammerstrøm, and N. Sathe. 

2017. “Searching for studies: 

A guide to information retrieval 

for Campbell systematic 

reviews.” Campbell Systematic 

Reviews 13 no. 1: 1-73. 

https://onlinelibrary.wiley.com/

doi/10.4073/cmg.2016.1. 

112 National Institute of Justice | NIJ.ojp.gov

guides from the Center for Problem-Oriented Policing on homeless encampments, 

people with mental illness, and several traffic safety problems. The big picture, though, 

is that most of the attention so far has been devoted to assessing the evidence on what 

works in reducing crime. This is completely understandable, but it means that there 

is still a lot of work to be done to support evidence-based policing in general, not just 

evidence-based crime control. Police agencies have multiple bottom lines for which they 

are responsible; therefore, they need to know what works best across a wide range of 

outcomes, not just one.

Systematic Reviews

“Systematic reviews are important for communicating high-level research findings to practitioners 

and policymakers. Yet, there are good reasons why in crime reduction, unlike in medicine, systematic 

reviews are not a mainstay of professional practice. First, high-quality primary evaluations are rare 

and for some topics virtually absent (e.g., organized crime, terrorism, modern slavery). Although 

‘empty’ systematic reviews may be useful for researchers, they are of little utility to practitioners. 

Second, there is a tendency for systematic reviews to focus on studies published in scientific 

journals. Failure to consult the ‘grey literature’ of government and practitioner reports, which 

comprise a sizable proportion of the crime reduction literature, may give rise to biased findings and 

neglect potentially important information. Finally, the methods used to quantitatively synthesize 

data from primary studies can be complex, and effectively communicating these methods to a lay 

audience is challenging.”

Source: Bowers, K., L. Tompson, A. Sidebottom, K. Bullock, and S. Johnson. 2017. “Reviewing evidence for evidence-based policing.” 

In J. Knutsson and L. Tompson, eds., Advances in evidence-based policing. London: Routledge, 102.
Evidence-Based Policing in 45 Small Bytes 113

BYTE 43

Putting Evidence to Use

Several examples presented earlier in this guide illustrate how evidence should be used:

• Chula Vista, California — The police department used data and analysis to identify a 

specific chronic problem (domestic violence calls and crimes), reviewed the evidence 

base for promising alternatives, implemented and evaluated a new protocol in a pilot 

district with another district serving as a comparison area, found that the new protocol 

was more effective than past practice, and then expanded it citywide.

• Austin, Texas — An existing curfew law was criticized by activists and political 

leaders. The police department reviewed the evidence base, discovering that such 

laws had not been found effective and often had disparate impact, then took the 

additional step of analyzing its own use of the curfew law, finding inconsistent 

application. The agency concluded that the law was not an essential tool for reducing 

crime and disorder, so it did not oppose the law’s repeal.

• Eau Claire, Wisconsin — Officers in the police department complained of back pain 

and suggested switching from the traditional duty belt to load-bearing vests. The 

agency partnered with a local university to do a six-month study, with 30 officers 

rotating between the belt and the vest. Results indicated less pain with the vests, so 

the department made the switch in equipment.

An interesting feature of all three of these examples was careful attention to local 

context. Chula Vista could simply have adopted a promising practice from some other 

jurisdiction, but instead it adopted elements from several programs that had been 

evaluated positively, combined them into its own tailored approach, and then conducted 

its own field test. Austin could have looked at the existing research on juvenile curfews 

and decided to abandon the law right then, but it took the extra step of analyzing its 

own implementation and enforcement before making a final decision. Eau Claire could 

have made an executive decision on whether to switch equipment based on personal 

preference, vendor claims, or existing medical evidence, but instead it took the time to 

test the vests on its own officers.

In these examples, evidence had its seat at the table, along with data, analysis, law, 

politics, and professional judgment. In addition, Chula Vista sought feedback from 

officers and victims, whereas Eau Claire’s evidence was mainly officer self-reports of 

back pain. In Austin, commanders’ experience and professional judgment played an 
SUGGESTED

READING

Weisburd, D., and P. Neyroud. 

2011. “Police science: 

Toward a new paradigm.” 

New Perspectives in Policing. 

Harvard Kennedy School 

of Government, Executive 

Session on Policing and Public 

Safety. Washington, DC: U.S. 

Department of Justice, National 

Institute of Justice. https://

www.ncjrs.gov/pdffiles1/

nij/228922.pdf. 

114 National Institute of Justice | NIJ.ojp.gov

important role and initially weighed in favor of keeping the juvenile curfew, until evidence 

and analysis convinced them that the law was not as important a tool as they had 

believed. None of these situations was decided by the scientific method alone — the 

evidence was persuasive, but other factors could have tipped the decisions in a different 

direction.

It remains to be seen whether policing will eventually develop an evidence base that 

is so complete and compelling that it will occupy the primary role in decision-making. 

The evidence base of policing might someday become so robust that there will be a 

WebMD-style app: Type in the symptoms and get back a diagnosis and recommended 

treatment. Alternatively, that might not ever come to pass. Diagnosing and responding 

to community and organizational problems — crime, disorder, fear, risky behavior, 

discrimination, homelessness, mental illness, substance abuse, morale, stress, burnout, 

injustice — might be significantly less clear-cut than dealing with illnesses in the 

human body (which isn’t really so clear-cut either, of course). Predicting how something 

will develop in the future is always treacherous, but at the present time the less 

programmable scenario seems more realistic.

Besides the key foundational ingredients emphasized in this guide — data, analysis, 

evaluation, testing, and finding existing evidence — some additional organizational steps 

have been recommended to help ensure that evidence is considered when decisions 

are made. The next byte goes into more detail about the training, policies, and agency 

champion needed for implementing evidence-based policing.

Why Be Evidence-Based?

“The importance of EBP [evidence-based policing] lies in the premise that police should have an 

ethical duty to employ the best evidence-based practices that reduce crime and calls for service 

while doing the least amount of harm to the community. If police managers do not have a grasp of 

whether they are using the city‘s resources in the most effective and efficient way, then they are 

not using the taxpayers’ monies wisely. What duty does the police department owe to the public? 

Is public safety a sacred cow that is given a wide berth without determining cost, effectiveness, 

efficiency, or harm to the public, or should the police be held to a higher standard?” 

Source: Mitchell, R.J. 2019. “A light introduction to evidence based policing.” In R.J. Mitchell and L. Huey, eds., Evidence based 

policing: An introduction. Bristol, UK: Policy Press, 12.
Evidence-Based Policing in 45 Small Bytes 115

BYTE 44

Creating an EvidenceBased Agency

I

t is one thing to take an evidence-based approach to a particular challenge or 

problem, but another thing to establish and sustain evidence-based policing (EBP) 

as an agency’s normal method of operation. Using data, analysis, and research to 

complement experience and professional judgment, day in and day out, is the objective. 

Making it happen requires effort and commitment.

The key ingredients for EBP have been outlined throughout this guide. To be evidencebased, an agency needs the following:

• A clear understanding of the multiple bottom lines of policing — the outcomes that 

matter most.

• Data on external conditions, internal conditions, and performance.

• Analysis to identify and diagnose patterns and problems, both external and internal.

• Evaluation of current practices, and testing of new ones, to find out how effective (or 

ineffective) they are.

These key EBP ingredients do not occur on their own. In small agencies, it might only 

require focus and disciplined thinking, whereas in large agencies it requires resources 

and staff (data scientists, analysts, researchers). Beyond these baseline needs, agencies 

that have led the way in adopting EBP have identified some additional measures that 

deserve consideration:56

• EBP Associations — Membership organizations focused on EBP have formed in 

several countries, one being the American Society of Evidence-Based Policing.57

Key agency staff should be encouraged to join and participate in networking and 

conferences.

• Research Partnerships — Agencies should look for opportunities to collaborate 

with research partners to help with evaluation of current practices, testing of new 

alternatives, and other research tasks that require special skills or an independent 

assessment. Although differences in timetables, terminology, and career incentives 

56 Martin, P. 2019. “Moving to the inevitability of evidence based policing.” In R.J. Mitchell and L. Huey, eds., Evidence 

based policing: An introduction. Bristol, UK: Policy Press, 199-213.

57 See https://www.americansebp.org. 
116 National Institute of Justice | NIJ.ojp.gov

can sometimes complicate police-researcher interactions, establishing an ongoing 

partnership can help in developing productive collaboration.58

• Research Committee — Agencies should consider establishing a research 

committee with two main responsibilities: (1) identifying important research needs 

within the agency and (2) helping screen, prioritize, and coordinate external requests 

for researcher access to the agency and its data.

• EBP Champion — Agencies should consider assigning to someone in the agency 

the specific responsibility for ensuring that the best available scientific evidence is 

considered whenever the agency is making decisions about policies, programs, and 

practices.

• Formal Policy — Agencies should consider adopting a formal policy or other directive 

that enshrines the agency’s commitment to using data, analysis, research, and 

evidence and that specifies any associated procedures, such as establishment of a 

research committee, appointment of an EBP champion, and setting a timetable for 

periodic evaluation of programs.

• Training — Agencies should incorporate training at various levels (recruit, supervisor, 

manager, commander) that demystifies EBP and emphasizes its practical value. Of 

equal importance is making sure that what is taught in police training reflects the 

best available evidence on every topic, and that how it is taught is based on evidence 

about how students and trainees learn.

• Reinforcement and Accountability — Performance evaluation rubrics, study 

materials for promotion, and promotion decisions should all incorporate and reward 

staff awareness and adoption of EBP. Unit commanders, program managers, and 

others in the agency should be held accountable for using the best available evidence 

when making decisions.

• Compstat — Agencies should integrate EBP into their Compstat-style systems so 

that responses to current crime and related problems are guided by analysis and 

evidence, not just a snapshot of recent data. When commanders are asked, “What are 

you doing about that problem?” their responses should be informed by analysis and 

evidence.

• EBP Unit — Some agencies have taken the step of creating an EBP Unit with the 

responsibility for infusing EBP throughout the organization. Data, analysis, evaluation, 

and research can be centralized in the unit, or simply coordinated by it. Design as a 

skill set is also helpful in the development of new systems, processes, and programs.

These kinds of organizational measures should help solidify EBP within an agency so 

that it doesn’t fall by the wayside with the first budget crunch or change in leadership. 

Equally important is to work on developing an evidence-based culture throughout the 

organization. Everyone in the agency should be encouraged to ask “why?” on a regular 

basis: Why has this problem persisted? Why haven’t we evaluated this program? Why 

58 Alpert, G.P., J. Rojek, and J.A. Hansen. 2013. Building bridges between police researchers and practitioners: Agents 

of change in a complex world. Washington, DC: U.S. Department of Justice, National Institute of Justice. NCJ 244345. 

https://www.ncjrs.gov/pdffiles1/nij/grants/244345.pdf. 
SUGGESTED

READING

New Zealand Police. “Blueprint 

for evidence-based policing.” 

2018. Wellington, NZ: New 

Zealand Police.

Evidence-Based Policing in 45 Small Bytes 117

do we do things this way? Staff members who demonstrate critical thinking, problem 

solving, creativity, and an experimental approach to working effectively should be 

recognized and rewarded.

One agency that has set a course toward full-fledged EBP is the New Zealand Police. 

In 2018, they published the “Blueprint for Evidence-Based Policing,” a three-year 

implementation plan spearheaded by their newly created Evidence-Based Policing 

Centre.59 Besides incorporating many of the principles and components discussed 

throughout this guide, the Blueprint is tightly coupled to the agency’s “Our Business” 

document, which succinctly presents “Our Purpose, Our Mission, Our Vision, Our 

Motto, Our Values, Our Goals, Our Strategies, Our People, Our Partnerships, and Our 

Transformation Program,” with the overarching theme of “Policing Through a Culture of 

High Performance.”60 In other words, EBP isn’t just a new initiative for the New Zealand 

Police. Rather, it is an integral part of how the agency intends to deliver the best possible 

police service and maximize its achievement of bottom-line outcomes.

Agencies that want to adopt and sustain EBP should take a cue from the New 

Zealand Police. Having a detailed plan helps keep things on track during the period of 

implementation, while clear and succinct statements of values, strategies, and themes 

help convey the kinds of emotion, pride, and purpose that can reassure officers that 

the agency is going in a positive and meaningful direction — toward better and more 

effective policing — which reinforces the practical importance of EBP.

Blueprint for Evidence-Based Policing

“Evidence-based policing presents an opportunity for New Zealand Police to embed a foundation of 

evidence-based best practice throughout all of its operations and provide confidence to our frontline, 

leadership, and wider New Zealand public, that what we do, does work.”

“Evidence-based policing supports our high performance culture with tools, technology and capability 

to embed evidence-based practice. Providing our people with the appropriate decision-making 

tools will give our people the confidence to deliver on Our Business. Aligned to Prevention First and 

Police High Performance Framework (PHPF), EBP also provides us with the research and evidence 

to inform our practice on what prevents harm, opportunities to improve well-being and to inform our 

deployment model.”

“Having seen the impact of research and evidence as a result of initiatives such as Family Violence 

Intervention Evaluation and the Crime Harm Index, we now need to expand the reach of EBP far 

beyond the existing EBP Centre, and embed the culture and ways of working throughout every 

district, service centre, and business group.”

Source: New Zealand Police. “Blueprint for evidence-based policing.” 2018. Wellington, NZ: New Zealand Police, 2.

59 New Zealand Police. “Blueprint for evidence-based policing.” 2018. Wellington, NZ: New Zealand Police.

60 See https://www.police.govt.nz/about-us/publication/our-business.
118 National Institute of Justice | NIJ.ojp.gov

BYTE 45

Continuous Improvement

T

he most effective organizations are those that never stop looking for ways to 

get better. One might wish for a big discovery — a “silver bullet” that solves 

all problems and maximizes performance for all time — but the reality is that 

people come and go, technology evolves, new laws are enacted, and new social issues 

arise. Every law enforcement agency has to adapt to changing internal and external 

conditions. Merely surviving can be quite a challenge for some organizations in turbulent 

environments, but the real objective should be to improve, not just survive.

Properly understood, evidence-based policing is the main driver of continuous 

improvement in policing. Law enforcement agencies position themselves to keep getting 

better when they focus on the multiple bottom-line outcomes of policing, rely on data to 

systematically measure how things are going, analyze problems that are encountered, 

evaluate current practices and test new ones, and look for evidence throughout the 

profession about what works best. Nothing is guaranteed, of course, but adding data, 

analysis, research, and evidence to police experience and professional knowledge is 

most likely to produce positive results in the face of ever-changing conditions.

Four interrelated perspectives are recommended to help sustain momentum for 

continuous improvement:

1. Eyes on the prize — It takes intentional effort to keep any organization focused 

on what really matters, because it is so easy to confuse means and ends, outputs 

and outcomes. That is why the multidimensional bottom lines of policing have been 

emphasized repeatedly in this guide.

2. Small steps — Although new technology and new discoveries may sometimes enable 

big advances in effectiveness, incremental improvements are more common. The 

agency that keeps looking for ways to nudge performance in a positive direction is 

most likely to keep getting better. 

3. Learning from error — Mistakes are inevitable. The most effective organizations are 

those that seize the opportunity to learn from errors in order to prevent them from 

happening over and over.61 Otherwise, mistakes are bound to be repeated, which cuts 

into effectiveness and imposes a heavy drag on continuous improvement.

61 Doyle, J.M. 2014. “Learning from error in the criminal justice system: Sentinel event reviews.” In Mending justice: 

Sentinel event reviews. Special Report. Washington, DC: U.S. Department of Justice, National Institute of Justice, 3-18. 

NCJ 247141. https://www.ncjrs.gov/pdffiles1/nij/247141.pdf.
SUGGESTED

READING

National Institute of Justice. 

Mending justice: Sentinel 

event reviews. 2014. Special 

Report. Washington, DC: U.S. 

Department of Justice, National 

Institute of Justice. NCJ 

247141. https://www.ncjrs.

gov/pdffiles1/nij/247141.pdf. 

Evidence-Based Policing in 45 Small Bytes 119

4. All hands on deck — The front-line personnel who actually do the work of the 

organization are most aware of inefficiencies and reasons for weak performance. A law 

enforcement agency that can inspire and reward employees who identify problems 

and create solutions is wisely taking full advantage of its talented workforce and is 

most likely to enjoy sustained achievement of the policing outcomes that matter.62

Systems Thinking and Continuous Improvement

“The systems approach fosters clear continuous improvement through a program of innovation, 

meaningful performance measurement and worker engagement. It promotes evidence-based 

priorities, devolved responsibility, organizational trust and a culture of ongoing learning to engender 

an organizational climate where energy is focused on achieving overall purpose from the customer’s 

or service user’s perspective.”

Source: Guilfoyle, S. 2013. Intelligent policing: How systems thinking methods eclipse conventional management practice. 

Devon, UK: Triarchy Press, 1.

62 Goldstein, H. 1990. Problem-oriented policing. New York: McGraw-Hill, 28.

Evidence-Based Policing in 45 Small Bytes 121

Suggested Readings

This list is a compilation of the suggested readings identified throughout this guide, along 

with a few additional sources that are easily accessible online.

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Alpert, G.P., J. Rojek, and J.A. Hansen. 2013. Building bridges between police researchers 

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grants/244345.pdf. 

Baumgartner, F.R., D.A. Epp, and K. Shoub. 2018. Suspect citizens: What 20 million traffic 

stops tell us about policing and race. Cambridge, UK: Cambridge University Press.

Behavioral Insights Team. 2019. Behavioral insights for building the police force of 

tomorrow. https://www.bi.team/wp-content/uploads/2019/01/BIT-Police-report_MKV5-

WEB.pdf. 

Braga, A.A., and E.F. Davis. 2012. “Evidence-based policing in practice: The case of Safe 

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Brodeur, J.-P., ed. 1998. How to recognize good policing: Problems and issues. Thousand 

Oaks, CA: Sage.

Campbell, D.T., and J.C. Stanley. 1963. Experimental and quasi-experimental designs for 

research. Boston: Houghton Mifflin.

Clarke, R.V., and J.E. Eck. 2005. Crime analysis for problem solvers in 60 small steps. 

Washington, DC: U.S. Department of Justice, Office of Community Oriented Policing 

Services. https://www.popcenter.org/sites/default/files/library/reading/PDFs/60Steps.pdf. 

Clary, K. 2018. “Utilizing data and science to reduce serious injury and fatality crashes on 

rural roadways.” Translational Criminology (Fall): 12-13, 24. https://cebcp.org/wp-content/

TCmagazine/TC15-Fall2018. 
122 National Institute of Justice | NIJ.ojp.gov

Cockbain, E., and J. Knutsson, eds. 2015. Applied police research: Challenges and 

opportunities. New York: Routledge.

Coli, V., N. Edwards, S. Haertsch, T. Kearney, W. Kerr, and D. Youngs. 2018. “Kicking down 

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and New Zealand Journal of Evidence Based Policing 3 no. 2 (Summer): 39-45. https://www.

anzsebp.com/wp-content/uploads/2019/09/ANZSEBPSummer18_compressed.pdf. 

Cordner, G. 2010. Reducing fear of crime: Strategies for police. Washington, DC: U.S. 

Department of Justice, Office of Community Oriented Policing Services. https://cops.

usdoj.gov/RIC/Publications/cops-p173-pub.pdf. 

Eck, J.E. 2002. Assessing responses to problems: An introductory guide for police 

problem-solvers. Tool Guide No. 1. Washington, DC: U.S. Department of Justice, Office 

of Community Oriented Policing Services. https://cops.usdoj.gov/RIC/Publications/copsp034-pub.pdf. 

Escamilla, J., J. Reichert, M. Hillhouse, and A. Hawken. 2018. “BetaGov supports 

practitioners and evaluators in conducting randomized control trials to test criminal 

justice programs.” Translational Criminology (Fall): 29-31. https://cebcp.org/wp-content/

TCmagazine/TC15-Fall2018. 

Eterno, J.A., and E.B. Silverman. 2012. The crime numbers game: Management by 

manipulation. Advances in Police Theory and Practice Series. Boca Raton, FL: CRC 

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Falck, C. 2018. “New Zealand Evidence Based Policing Centre.” Police Science: Australia 

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compressed.pdf. 

Federal Bureau of Investigation. 2018. “Clearances.” Crime in the United States, 2017.

Washington, DC: U.S. Department of Justice, Federal Bureau of Investigation, Uniform 

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Fleming, J., and R. Rhodes. 2017. “Experience is not a dirty word.” Policy & Politics Journal 

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Fox, A.M., K.J. Novak, and J. McHale. 2015. “Using social network analysis to guide 

law enforcement strategies.” Translational Criminology (Fall): 6-8. https://cebcp.org/wpcontent/TCmagazine/TC9-Fall2015. 

Gascón, G., and T. Foglesong. 2010. “Making policing more affordable: Managing costs 

and measuring value in policing.” New Perspectives in Policing (December). Washington, 

DC: U.S. Department of Justice, National Institute of Justice. NCJ 231096. https://www.

ncjrs.gov/pdffiles1/nij/231096.pdf. 
Evidence-Based Policing in 45 Small Bytes 123

Gross-Shader, C., and C. Gill. 2013. “Beyond the police: Building ‘translation 

communities’ for evidence-based policing in Seattle.” Translational Criminology (Spring): 

17-19. https://cebcp.org/wp-content/TCmagazine/TC4-Spring2013. 

Guilfoyle, S. 2013. Intelligent policing: How systems thinking methods eclipse conventional 

management practice. Devon, UK: Triarchy Press.

Hegarty, T., L.S. Williams, S. Stanton, and W. Chernoff. 2014. “Evidence-based 

policing at work in smaller jurisdictions.” Translational Criminology (Spring): 14-15, 18. 

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Henning, K., and G. Stewart. 2015. “Improving academic-police partnerships: 

Observations and suggestions from a long-term partnership in Portland, Oregon.” 

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Herrington, V. 2016. “The importance of evidence based policing for the thinking 

professional police officer.” Police Science: Australia and New Zealand Journal of 

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Kimerer, C. 2014. “Looking forward, looking back: Reflections on the value of evidencebased practices in policing.” Translational Criminology (Fall): 16-17. https://cebcp.org/wpcontent/TCmagazine/TC7-Fall2014. 

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Kugley, S., A. Wade, J. Thomas, Q. Mahood, A.-M.K. Jørgensen, K. Hammerstrøm, and 

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124 National Institute of Justice | NIJ.ojp.gov

Lum, C., and C.S. Koper. 2017. Evidence-based policing: Translating research into practice.

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McGough, M.Q. 2018. “Research in the ranks: Empowering law enforcement to drive 

their own scientific inquiry.” NIJ Journal 280 (October). NCJ 252034. https://nij.ojp.gov/

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Mitchell, R.J., and L. Huey, eds. 2019. Evidence based policing: An introduction. Bristol, 

UK: Policy Press. 

Mitchell, R.J., C.W. Telep, and C. Lum. 2017. The ten-step guide for conducting in-house 

experimental evaluations: A guide for law enforcement practitioners. Fairfax, VA: George 

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Moore, M.H., and A. Braga. 2003. The “bottom line” of policing: What citizens should value 

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Muhlhausen, D.B. 2018. “Director’s corner: Pushing the edge on evidence-based 

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Valuable Resources

American Society of Evidence-Based Policing — https://www.americansebp.org

Australia & New Zealand Society of Evidence Based Policing — http://www.anzsebp.com 

Campbell Collaboration — https://campbellcollaboration.org 

The Canadian Society of Evidence-Based Policing — https://www.can-sebp.net

Center for Problem-Oriented Policing, Arizona State University — https://www.popcenter.org

Crime Reduction Toolkit, What Works Network, U.K. College of Policing — 

https://whatworks.college.police.uk/toolkit/Pages/Welcome.aspx

CrimeSolutions.gov, National Institute of Justice — https://www.crimesolutions.gov

The Evidence-Based Policing App — http://www.evidence-basedpolicing.org

Evidence-Based Policing Matrix, Center for Evidence-Based Crime Policy — 

https://cebcp.org/evidence-based-policing/the-matrix

Law Enforcement Advancing Data and Science (LEADS) Programs, National Institute 

of Justice — https://www.nij.gov/topics/law-enforcement/Pages/law-enforcementadvancing-data-and-science-program.aspx

National Law Enforcement Applied Research & Data Platform, National Police 

Foundation — https://www.nationallawenforcementplatform.org

Society of Evidence Based Policing — https://www.sebp.police.uk


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