U.S. Department of Justice

Office of Community Oriented Policing Services

By

Lorraine Mazerolle 

David W. Soole

Sacha Rombouts

Griffith University, 

School of Criminology 

and Criminal Justice

Disrupting Street-Level Drug Markets

No. 1

Crime Prevention

Research Reviews

The Campbell Collaboration

Crime and Justice Group
Suggested citation: 

Mazerolle, Lorraine, David W. Soole, and Sacha 

Rombouts. Crime Prevention Research Reviews No.1: 

Disrupting Street-Level Drug Markets. Washington, 

D.C.: U.S. Department of Justice Office of Community 

Oriented Policing Services, 2007.

The Campbell Collaboration Crime and Justice Group 

(http://www.campbellcollaboration.org/ccjg) is an 

international network of researchers that prepares, 

updates, and rapidly disseminates systematic reviews of 

high-quality research conducted worldwide on effective 

methods to reduce crime and delinquency and improve 

the quality of justice.
Contents

Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

How Studies Were Chosen for the Review. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Research Review. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

A Classification of Policing Strategies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Disrupting Street Drug Markets Using Police-Only 

Approaches (Hot Spots Policing) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Disrupting Street Drug Markets Using 

Community-Wide Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Disrupting Street Drug Markets Using Geographically Focused 

Approaches (POP and Third Party Partnerships) . . . . . . . . . . . . . . . . . . . . . 18

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

iii

 Acknowledgements

This research was sponsored by a grant from Turning Point Alcohol and Drug Centre, 

Melbourne, Australia, to Griffith University. The authors are appreciative of feedback on the 

project from David Weisburd, Alison Ritter, Jon Caulkins, and Peter Reuter. Special thanks 

to David Wilson for his help with our analytic approach. Thanks also to Brigitte Bouhours 

for her research assistance. Address all correspondence to Lorraine Mazerolle (l.mazerolle@

griffith.edu.au), School of Criminology and Criminal Justice, Griffith University (Mt. 

Gravatt Campus), Brisbane, Australia 4111.

v

Introduction

Our review finds that ... strategic crime-control 

partnerships with a range of third parties are more 

effective at disrupting drug problems than law 

enforcement-only approaches.
6

Introduction

Police throughout the world have implemented a range of strategies and approaches to 

disrupt street-level drug problems. Some of these approaches to street-level drug law 

enforcement include crackdowns, raids, buy-busts, third party policing, and problemoriented policing. To determine what is most effective in street-level drug enforcement 

interventions, we reviewed all available, scientifically rigorous1 academic studies evaluating 

a wide range of street-level drug law enforcement interventions. Our review was limited to 

studies that used experimental or quasi-experimental approaches and excludes evaluation 

studies that did not meet the minimum threshold of scientific rigor advanced by The 

Campbell Collaboration Crime and Justice Group (see http://www.campbellcollaboration.

org/guidelines.asp). The review differs in its approach from the popular ProblemOriented Guides for Police (POP Guides) Series of publications produced by the Office 

of Community Oriented Policing Services (COPS Office), U.S. Department of Justice, 

that use somewhat broader standards for evidence. Any overlap or differences between the 

findings of this report and the POP Guides should be understood within this context. 

We adapted a classification of generic law enforcement approaches to be able to compare 

and contrast four commonly recognized drug law enforcement approaches 

(Weisburd and Eck, 2004):

Community-wide policing approaches that involve a wide array of diverse 

interventions that rely on the police forging partnerships (e.g., with other police 

agencies, community entities, regulators, city inspectors), and implementing 

strategies that are targeted at relatively large areas such as across entire communities 

or neighborhoods to address drug markets.

Geographically focused policing approaches that typically involve the use of problemsolving models and/or partnerships with third parties (such as regulators, service 

providers, government agencies), are targeted at drug hot spots, and include a wide 

array of interventions.

1.

2.

1

The evaluation results included in this report represent 

a subset of studies that met Campbell Collaboration 

review criteria (see http://www.campbellcollaboration.

org/guidelines.asp) as well as a number of evaluations 

that were ultimately rejected for the Campbell review, 

but still provided sufficient scientific rigor (experimental 

and control groups) to inform debate as to what works 

and what does not in disrupting street-level drug 

markets (see an annotated bibliography of all retrieved 

studies in Mazerolle, L., D. Soole, and S. Rombouts. 

“Drug Law Enforcement: The Evidence.” Monograph 

No. 05. DPMP Monograph Series. Fitzroy: Turning 

Point Alcohol and Drug Centre, 2005.).
7

Hot-spots policing (directed patrols, crackdowns, raids) that involve police-only 

activities and are geographically focused on drug hot spots.

Standard traditional approaches to drug law enforcement that are unfocused and rely 

principally on law enforcement resources (e.g., routine patrols, arrests). 

Our review finds that geographically focused interventions using a range of approaches 

(including problem-oriented policing, third-party policing, and Crime Prevention Through 

Environmental Design [CPTED]) that typically involve strategic crime-control partnerships 

with a range of third parties are better than community-wide policing approaches that 

rely on partnerships to reduce drug and disorder problems across neighborhoods plagued 

with drug problems. Our review also finds that either type of partnership approach (i.e., 

geographically focused or community-wide approaches that use partnerships) is likely to 

be more effective at disrupting drug problems than law enforcement-only approaches (e.g., 

crackdowns, raids, directed patrols) that target drug hot spots. Unfocused law enforcementonly approaches to dealing with drug problems are a distant last.

3.

4.
How Studies Were Chosen for the Review

The research included in this review is limited to studies that use experimental or quasi-experimental 

designs and meet the criteria for rigor as laid out in The Campbell Collaboration Crime and Justice 

Group review criteria (see http://www.campbellcollaboration.org/guidelines.asp). It is important to 

note that other pieces of evidence regarding the effectiveness of various responses were excluded from 

this research. The popular series of Problem-Oriented Guides for Police (POP Guides) published by 

the COPS Office differs significantly from this review because the standards for inclusion of evidence 

are less tied to the use of experimental designs and thus include a wider range of evidence. 

Our review includes interventions initiated, managed, and/or implemented by police to reduce 

or prevent illicit drug use, drug dealing, and the associated problems at drug-dealing places. We 

decided to exclude evaluations of police-led school-based drug education programs from this review. 

Evaluations of school-based drug education programs have been reviewed extensively elsewhere and 

use outcome metrics that differ from metrics used in most other police interventions. Our review 

also does not include judicial, correctional, or treatment interventions, or antidrug strategies run 

exclusively by nonpolice personnel (e.g., customs, military, taxation). We include interventions that 

target only illicit drugs (e.g., heroin, cocaine, methamphetamine, cannabis). Strategies targeting 

illegal use or sale of licit substances such as alcohol, tobacco, or solvents, and illicit use or trafficking 

of prescription drugs are not included. Interventions reported in this paper were targeted at the street 

(i.e., neighborhood) level. The review was not restricted to a specific period and relevant studies 

written in languages other than English were obtained and translated wherever possible. Eligible 

studies include published as well as unpublished works (journal articles, theses/dissertations, reports, 

books, book chapters, and conference papers). See Mazerolle, Soole, and Rombouts (2006 and 2007) 

for further details of the systematic search methodology.

8
Research Review

In this paper, we review the results of 117 

scientifically rigorous street-level drug law 

enforcement evaluation studies.
10

A Classification of Policing Strategies

In 2000, the National Research Council (NRC) of the National Academy of Sciences 

convened a special committee of police experts to harness what we know works (and 

what we know does not) in policing (see Skogan, 2004; Skogan and Frydl, 2004). One 

outcome from the NRC deliberations was a much needed new conceptualization of police 

approaches to crime control (see Weisburd and Eck, 2004). In their review of the relative 

effectiveness of different approaches to law enforcement, Weisburd and Eck developed a 

classification of approaches highlighting two areas: one relating to the diversity of approaches

employed, and the other the focus of the approach. We have adapted this classification system 

to suit our review of drug law enforcement strategies (see Figure 1). 

Community-wide 

Partnerships POP and Partnerships

Standard Model Hot Spots

Diversity of Approaches

Level of Geographic Focus

Mostly law enforcement Wide array

Low High

Figure 1: Classification of Street Drug Market Policing Approaches.

(Adapted from Weisburd and Eck, 2004)
11

The first dimension is “Level of Focus,” ranging from crime-control approaches that are 

unfocused (approaches that cover large geographic areas) to those approaches that are 

highly focused (approaches that target small geographic hot spots of drug problems). The 

second dimension involves the degree to which police-led crime-control approaches involve 

a wide array of intervention approaches including third-party partnerships (regulators, 

inspectors, community entities). Our review of street-level drug law enforcement uses 

this law enforcement classification model to examine the types of approaches to drug law 

enforcement that are most effective at reducing drug and related crime problems. 

 In this paper we review the results of 117 scientifically rigorous street-level drug law 

enforcement evaluation studies: 29 hot spots, 33 community-wide, and 55 geographically 

focused interventions including both problem-oriented policing and intervention 

partnerships that did not follow the SARA process (scanning, analysis, response and 

assessment) but were geographically focused.2 In the evaluation studies that we reviewed, 

the effects of hot spots, community-wide, and geographically focused use of problemoriented policing and partnerships were compared to the effects of standard policing 

approaches that involved unfocused law enforcement-only responses such as rapid response 

and preventive patrols. 

Disrupting Street Drug Markets Using Police-Only Approaches 

(Hot-Spots Policing)

Our classification of drug hot-spots policing approaches includes crackdowns, raids 

(including search and seizures), undercover operations, arrests in drug-free zones, and 

directed, intensive patrol activities in drug hot spots. 

2 Interventions that operate to disrupt international illicit 

drug activity (such as crop eradication and interception 

at the point of importation) and statewide or regional 

multijurisdictional task forces are not included in this 

review because they target the wholesale or importation 

drug problem, not the street-level drug problem, which is 

the focus of this review.
12

Crackdowns on Street Drug Markets

Crackdowns are defined as “abrupt escalations in law enforcement activities that are 

intended to increase the perceived or actual threat of apprehension for certain offenses 

occurring in certain situations or locations” (Davis and Lurigio, 1996: 86). During 

crackdowns, police operations are typically highly visible and involve a large number of 

uniformed and/or undercover officers (Scott, 2002). Our review uncovered 23 studies 

that evaluated 20 separate crackdowns. Typically, crackdown interventions target harder 

drugs such as crack, cocaine, and heroin. Dealing and use were generally the drug-related 

behaviors targeted in the studies reviewed, with associated crime (especially property, 

violent, and disorder-related crime) also targeted in many instances. Typically, crackdowns 

aim to reduce drug supply by arresting dealers and disrupting street-level market activity, 

thus reducing the availability of drugs. 

There were a number of major trends in the results of the evaluated interventions: 

Crackdowns were largely ineffective in disrupting drug problems such as use, dealing, 

and drug offenses.

Crackdowns appeared to have more success addressing associated crime problems, 

such as property crime and violent crime, among others.

Displacement (both spatial and temporal) of drug and crime problems was a 

common problem.

Crackdowns tended to be effective at reducing drug problems only in the short term. 

Crackdowns generally do not align with harm-reduction policy and tend to have a 

negative impact on patterns of drug use, injecting practices, and demand for treatment. 

Certain geographical and drug market characteristics influence the effectiveness 

of crackdowns. Geographically contained areas (by rivers, freeways, borders, for 

example) were typical places that led to more successful effects of crackdowns.

•

•

•

•

•

•
13

Drug market characteristics, such as pre-intervention establishment of the market, 

were also found to influence the effectiveness of crackdowns, with less established 

markets being more vulnerable to the positive effects of crackdowns than more 

entrenched drug markets.

Our review suggests that crackdowns tend to have minimal, short-term effects on drug, 

crime, and disorder problems. Some studies, however, suggest that crackdowns may 

indeed be effective under certain circumstances. It is likely that the right ingredients for a 

planned crackdown (e.g., timing, location, type of drug, type of market place, method of 

sales) must be identified before a crackdown can be successful. The short-term benefits of 

crackdowns can be “maintained” only when follow-up strategies (e.g., “seeding programs”) 

are implemented in the hot spots to maintain the gains of the crackdown and reduce the 

likelihood of the marketplace being reinstated. 

Raids on Drug-Using Places

Raids are specifically localized search-and-seizure-type operations that are targeted at places 

with drug use and low-level drug dealing problems (as opposed to drug manufacture 

locations —see below for Search and Seizures to Target Drug Labs). Raids generally 

target residential and commercial (such as clubs, motels) properties that are the source 

of numerous drug, crime, and disorder problems (e.g., calls for service, arrests, citizen 

complaints). Raids generally involve arrests and are typically highly visible, with the 

intention of acting as a deterrent to others.

Two evaluations of interventions that used raids to disrupt drug markets were identified, 

both of which were conducted in the United States. Raids generally target drugs such as 

crack and cocaine. Some of the findings from the evaluations included the following:

Raids were found to have an immediate effect on drug, crime, and disorder outcomes.

The effects of raids typically were of short-term duration and decayed rapidly when 

intervention was withdrawn.

•••
14

Areas with higher predictors of the risk of drug, crime, and disorder problems 

appeared more resistant to the effects of raids and the raids appeared to have seasonal 

effects on some outcome categories.

Undercover Operations 

Undercover operations include law enforcement activities such as undercover investigations, 

undercover drug buys, buy-busts, use of informants, and reverse stings. Generally, these 

activities do not occur in isolation but are one of many approaches used by police to target a 

specific problem. Such operations typically focus on drug-dealing locations.

Two evaluated interventions specifically restricted to undercover operations were identified 

through our systematic search. One of the interventions occurred in the United States and 

the other in Australia. The findings from the evaluations included the following:

No evidence of an impact of undercover operations on drug offenses (possession, 

trafficking, manufacturing, growing), individual drug use, or changes in the supply or 

demand of the drug market.

No evidence of an impact of undercover operations on associated criminal activity 

(e.g., property and violent offenses).

Directed Patrols on Drug Hot Spots

Directed patrols on drug hot spots are referred in the literature as “intensive policing,” 

“saturation patrols,” and “drug sweeps.” Directed patrols are distinguished from crackdowns 

because they typically do not involve large numbers of police or the degree of planning and 

coordination of crackdowns. Directed patrols are used to target any and all types of drugs 

and behavior, although dealing and use generally are targeted.

•

•

•
15

Only three studies were identified that specifically evaluated directed patrols of drug market 

areas. Of the reviewed interventions, two occurred in the United States and the other in 

Australia. There were a number of pertinent findings from these evaluations:

Increased patrols in drug markets that are not carefully planned or “directed” at hot 

times have little impact on drug and crime problems.

Drug sweeps resulted in a reduction in drug, gang, and crime outcomes. 

Search and Seizures to Target Drug Labs

With the increase in the use of chemical drugs such as methamphetamine throughout the 

1990s there has been an increasing need to develop strategies to address the consequent 

increase in manufacturing of such drugs (meth labs, clan labs). Such strategies generally 

involve intelligence gathering through numerous sources such as informants and citizen 

complaints. Based on this information, warranted searches are conducted on properties and 

locations suspected of drug manufacturing and drugs, equipment, and assets are seized. 

Two evaluated search-and-seizure interventions were identified in our systematic review of 

the evaluation literature. The programs specifically targeted small-time chemical drug labs 

producing methamphetamine. Both evaluations were from the United States and found 

that search-and-seizure interventions reduced the number of operating clandestine labs and 

subsequently reduced the supply of chemical drugs to the street.

Drug-Free Zones

Drug-Free Zones (DFZ) provide police with additional powers in their efforts to disrupt 

street drug dealing. Efforts to implement DFZs involve identifying areas prone to high 

drug and associated criminal activity as DFZs, and then providing police with the power to 

banish convicted drug offenders from these zones. ••
16

Two studies evaluated one DFZ intervention conducted in the United States; therefore, it is 

difficult to draw concrete conclusions about this kind of intervention. The findings included 

the following:

No evidence was shown of an effect of DFZs on drug arrests.

Evidence showed that drug activity became more concentrated and was displaced, 

suggesting perhaps that new players had entered the market or moved up the hierarchy.

Disrupting Street Drug Markets Using Community-Wide 

Approaches

A range of drug law enforcement approaches can be loosely grouped under the banner 

of community-wide drug law enforcement. These include police-led interventions that 

typically are unfocused (i.e., approaches that are generic to a city, town, or community) and 

involve partnerships (i.e., partnerships with local councils, community groups, regulators, 

inspectors, business groups, and other crime-control agencies). Our review searched for a 

range of community-wide drug law enforcement interventions and identified a number 

of tactics such as knock-and-talks, drug patrols, local police shop fronts, drug hot lines, 

foot and bike patrols, neighborhood revitalization, community mobilization, block watch, 

neighborhood watch, arrest referral, arrest diversion, and Weed and Seed strategies.

Generic Community-Wide Interventions 

Our review uncovered 15 evaluation studies of community-wide interventions that were 

implemented specifically to disrupt street-level drug problems (and included a drug 

outcome measure). In a majority of studies the interventions did not target a specific drug, 

but rather targeted all illicit drugs. Similarly, in most instances, a variety of drug-related 

behavior was targeted, including dealing, use, and manufacturing. Typically, both open-air 

and indoor drug markets are targeted by community-wide drug law enforcement initiatives. 

The major trends from the community-wide policing evaluations were these: ••
17

Weed and Seed programs that target street drug markets appear to be effective at 

reducing fear of crime and reducing disorder problems. Insignificant reductions in 

drug and other crime problems were recorded. 

Comprehensive, multi-agency neighborhood enhancement programs revealed small 

and generally insignificant decreases in crime, drug calls, and drug consumption, 

along with greater citizen satisfaction with the police.

Foot and bike patrols showed small reductions in drug-related arrests. 

Shop fronts (also known as “Cop Shops”) revealed improvements in quality of life, 

reductions in fear of crime, and increased police satisfaction with the community.

Arrest Referral Programs Across Communities 

Arrest referral programs can occur at a variety of access points in the criminal justice system 

process including during police custody, court referred, or through prison services. The 

programs reviewed here are restricted to those that occur at the level of police custody. The 

general strategy is to approach drug-abusing offenders while they are in police custody to 

inform and refer them, and in some instances provide them with access, to treatment services. 

We reviewed 11 interventions. Typically, arrest referral programs do not target a specific 

drug but rather are generic, targeting all illicit drugs and in some cases licit drugs as well 

(such as alcohol and prescription medicines). The U.K. is at the forefront of arrest referral, 

which is evident by the fact that the reviewed evaluations were conducted in either England 

(n=10) or Scotland (n=1). 

We found that arrest referral programs generally show reductions in subsequent drug 

use post arrest. 

•

•

•

•

•
18

Drug Diversion Programs

Our systematic review uncovered seven evaluations of drug diversion programs, all of which 

were conducted in Australia. The majority of the diversion programs that we reviewed 

involved cautioning with and without mandatory education sessions. In all instances, the 

general aim of the interventions was to reduce the pressure placed on the criminal justice 

system by diverting more minor drug offenders away from the system. In most cases, the 

drug targeted was cannabis. The results show the following:

Three of the seven studies reported reductions in use.

The Cannabis Expiation Notice (CEN) program in South Australia showed that 

those receiving CENs were better off on a range of important social outcomes 

(employment, accommodation, relationships, less contact with the criminal justice 

system).

Reductions in self-report offending were reported in two evaluations.

Improved police relations with the community were reported in three of the 

evaluations.

Disrupting Street Drug Markets Using Geographically Focused 

Approaches (POP and Third-Party Partnerships)

The National Research Council report classified highly focused interventions (focused on 

people, places, and victims) that involved an array of partnerships as “problem-oriented 

policing.” In our review of drug law enforcement evaluations, however, we uncovered 34 

studies that could be classified as using a problem-oriented policing approach. We also 

uncovered a number of interventions that met the criteria of forging partnerships and being 

focused, but did not follow the problem-oriented policing methods (i.e., the SARA model 

of scanning, analysis, response and assessment). 

•

•

•

•
19

These included, most notably, the use of third-party partners and the activation of civil 

remedies as well as Crime Prevention Through Environmental Design (CPTED) responses 

that were not part of a problem-oriented policing intervention. In total, we identified 54 

interventions that were geographically targeted drug law enforcement interventions that 

involved partnerships with an array of what Mazerolle and Ransley (2006) refer to as third 

parties. There also were two studies of CPTED responses that met the criteria for inclusion 

in the analysis.

Problem-Oriented Policing

Problem-oriented policing is defined as police efforts to scan for problems (problem places, 

people, or victims), analyze the nature of these highly specific problems, tailor responses 

to directly address the immediate causes of the problem, and then assess the effectiveness 

of the response (Goldstein, 1990). Problem-oriented policing is a focused strategy (either 

on problem people or places) and generally (yet not always) involves partnerships with 

nonpolice entities. In total, 34 problem-oriented policing evaluation studies were identified 

in our search that specifically addressed drug problems, with extremely positive results:

More than 70 percent (24 of 34) of the problem-oriented policing evaluations 

reported positive effects on drug outcomes.

Almost 80 percent (19 of 24) of the problem-oriented policing evaluations reported 

positive effects on nondrug outcomes (e.g., property, violent, disorder, offenses). 

In 8 of 12 evaluations assessing the phenomenon there was evidence of spatial 

displacement of crime.

In two of the evaluations a diffusion of crime-control benefits effect was reported.

In 15 evaluations improvements in the quality of life or community satisfaction were 

reported and a reduction in fear of crime was found in four evaluations.

•••••
20

Third-Party Policing, Drug Nuisance Abatement, and Civil Remedies 

Third-party policing involves multiple regulatory “nodes” coming together to solve a 

crime problem. Third-party policing occurs within a legal framework that establishes the 

authority for police to partner with or coerce third parties, the contexts in which they can 

do that, and the types of intervention this may produce (Mazerolle and Ransley, 2006). 

In third-party policing, the police create or enhance crime-control guardians in locations 

or situations where crime-control guardianship was previously absent or noneffective. 

Sometimes the police use cooperative consultation with community members, parents, 

inspectors, and regulators to encourage and convince third parties to take on more crimecontrol or crime-prevention responsibility. Central, however, to third-party policing is the 

use of a range of civil, criminal, and regulatory rules and laws to engage (or force) third 

parties into taking some crime-control responsibility (see Buerger and Mazerolle, 1998; 

Mazerolle and Ransley, 2006).

In our review, we identified 25 studies that evaluated 18 civil remedies, third-party policing, 

or drug nuisance abatement programs. Typically, these initiatives targeted all illicit drugs; 

however, a couple focused on crack and one study focused only on cannabis. Almost all 

evaluations (n=15) were conducted in the United States, with two others conducted in 

Canada and one in the U.K.

All evaluations identified in our review reported positive outcomes: 

Drug nuisance abatement, third-party policing, and civil remedies programs appeared 

to be effective in dealing with drug problems such as dealing and drug offenses (11 of 

11 evaluations reported intervention success). 

The programs appeared to also have success addressing associated crime problems, 

such as property, violent, and/or disorder-related offenses and calls for service (12 of 

12 evaluations reported intervention success).

Business owners were the most common third-party partner in the interventions. 

Improvements in quality of life were reported in 10 of the evaluated interventions. 

•

•

•

•
21

Displacement of drug and crime problems was not a major problem and occurred 

about as often as diffusion of benefits effects.

A civil remedy known as Anti-Social Behavioural Orders (ASBO) evaluated in the 

U.K. led to reductions in drug and criminal activity in the targeted area.

Crime Prevention Through Environmental Design

Crime Prevention Through Environmental Design (CPTED) involves strategies aimed at 

reducing crime by making appropriate changes in the physical environment of problem 

locations. CPTED involves a number of components including increasing the chance 

of detecting criminal behavior, increasing the risks and difficulty of committing criminal 

acts, and target hardening. Using CPTED to target drug problems typically involves a 

variety of strategies including installation of surveillance cameras, trimming of foliage, 

implementation of additional lighting, repairing of fences, limiting access to problem areas 

through road changes, removal of phone booths and bus stops used by drug users and 

dealers, and improved parking and trespassing signage.

We retrieved two studies that evaluated CPTED interventions specifically aimed at 

targeting drug problems. Both interventions occurred in the United States. The findings 

from the two evaluations were mixed:

One of the evaluated interventions provided evidence of a positive effect on both 

property crime and disorder, as well as reductions in fear of crime and improvement 

in the perception of police. 

The other provided evidence of a positive impact on drug and violent arrests, but no 

impact on property crime, or on fear of crime or perceptions of the police.

•

•

•

•
22

Conclusions

During the last 10 years, prominent scholars have studied and reviewed the effectiveness 

of generic law enforcement interventions. These reviews show that focused, partnershiptype law enforcement interventions that apply a wide range of sanctions generally are 

far more effective responses to ongoing crime problems than unfocused efforts relying 

entirely on law enforcement resources (Weisburd and Eck, 2004). Indeed, traditional 

law enforcement interventions at crime hot spots have been found to be effective, and 

problem-oriented policing (using a diversity of approaches) is a marked improvement 

over simply directing law enforcement resources to target places with drug problems. 

Reviews of generic law enforcement studies also find limited evidence to support 

unfocused, community-wide interventions. Community-wide interventions come third 

to problem-oriented and hot-spots policing interventions. The standard, unfocused, law 

enforcement-only approach is a distant last.

Our review of street-level drug law enforcement adapted this model to explore what works 

to disrupt street-level drug markets (see Figure 2). We generally find support for these 

earlier reviews of generic law enforcement approaches, with some important variations. Our 

review finds that geographically focused interventions (including problem-oriented policing, 

third-party policing, and CPTED initiatives) are better than community-wide approaches 

that use partnerships across a wide geographic area to reduce drug and disorder problems 

in neighborhoods plagued with drug problems. Our review also finds that either type of 

partnership approach (community-wide or geographically focused) is likely to be more 

effective at reducing drug problems than law enforcement-only efforts (e.g., crackdowns, 

raids, directed patrols) that target drug hot spots. That is, unlike the findings from reviews 

of generic law enforcement interventions, the evidence uncovered in our study suggests 

that police partnerships with a variety of entities (regulators, inspectors, business owners, 

local councils) that are community-wide or geographically focused policing approaches to 

tackling street-level drug market problems are more productive for reducing drug problems 

than law enforcement-only approaches focused on hot spots. In short, we find that police 

efforts to forge crime-control partnerships and build better police-citizen relationships are 

going to be a more effective approach to tackling street-level drug problems than simply an 

enforcement-only approach to policing drug hot spots.
Several policy implications emerge from our research. First, our research highlights the 23 general lack of high-quality evaluations of drug law enforcement interventions. Given that 

national budgets dedicate more than half of their drug policy funds toward law enforcement 

(the rest being made up of treatment, prevention, and harm-reduction spending), we argue 

for more careful investment in the evaluation of drug law enforcement at both the local 

and federal levels. Law enforcement agencies should be encouraged to partner with local 

universities and researchers to rigorously evaluate the effectiveness of their response efforts.

Second, the police will be most effective at reducing street-level drug problems when they 

work in partnership with third parties, whether they are partnerships within a problemoriented policing context or not. To reduce street-level drug problems, police need to 

improve police-citizen relations, forge partnerships with nonpolice agencies (i.e., third 

parties), utilize a range of civil remedies, and leverage additional resources to deal with a 

community’s drug problems. Policymakers need to find ways to encourage, initiate, and 

insist on partnership approaches for dealing with street-level drug problems. 

High

Community-Wide Partnerships

Some evidence to support the approach

Focused POP and Partnerships

Effective

Low

Police Only, Community-Wide 

Interventions

Does not work

Police Only Focus on 

Hot Spots

Mixed evidence

Low High

Figure 2: Summary of What Works to Disrupt Street Drug Markets.

Diversity of Approaches

Level of Geographic Focus
24

Finally, police need to consider the conditions that support street-level drug market activity. 

Careful analysis of the problem, in a manner consistent with the analysis component of 

the problem-oriented policing approach, can help police determine the most appropriate 

partners (health and safety inspectors, residents, truant officers, building code inspectors) 

and choose appropriate sanctions that are likely to reduce the opportunities for the street 

drug trade to flourish. Using geographic information systems and data from a wide variety 

of sources will certainly increase the capacity of police to understand the variability of street 

drug markets, even within relatively small geographic areas (Eck, 1994). 
References
26

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For More Information

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Washington, DC 20530

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