Appendix: Summary of Crackdown Studies
The table below summarizes published studies on crackdowns. Given the frequency and expense of crackdowns, the research is quite limited. The studies listed are not of equal value: some were better implemented than others, some were better evaluated than others. They used a variety of evaluation methods, some stronger than others. Accordingly, you should not use only this table to inform your decision-making about crackdowns. It only supplements the information provided in this guide's main text. Those interested should read the original study reports to better judge the reliability of the findings and conclusions.
Evaluations of police operations are always complicated. Many of the most important things you would want to measure are difficult to measure accurately, such as actual victimizations (as opposed to only those reported), unwitnessed violations, and police officers' discretionary actions. It is equally difficult to determine reliably what factors other than the crackdown might have contributed to the results, and whether and how the problem might have been displaced. Nevertheless, these studies comprise some of the best available information, however imperfect. More and better studies are needed, of course, but in the final analysis, no amount of research knowledge completely substitutes for the good judgment police decision-makers must exercise, taking many factors into account.
| Offenses Targeted | Jurisdiction | Year | Project/ Operation Name | Crackdown Tactic(s) | Evaluation | Deemed Effective | Evidence of Displacement/Diffusion of Benefits/ Residual Deterrence Effects | Evidence of Negative Effect on Police-Community Relations |
|---|---|---|---|---|---|---|---|---|
| All crimes | New York City (20 th Precinct) | 1966 | Extra police patrol (40% increase) | Green (1996) [Full text] and Sherman (1997) [Full text] (both citing Press, 1971) | Yes, reduced street crimes | Yes, spatial displacement to adjacent precincts | ||
| All crimes | Newark, New Jersey | 1978-79 | Newark Foot Patrol Experiment | Extra foot patrol | Police Foundation (1982) | No, but had a positive effect on public perceptions of safety | No, increased citizen satisfaction with police | |
| All crimes | Dayton, Ohio | Aggressive traffic enforcement | Weiss and Freels (1996) | No, did not reduce robbery or auto theft or have any measurable effect on traffic crashes | ||||
| All crimes | Indianapolis, Indiana | 1995 | Safe Streets Project | High volume of traffic stops in drug market areas; aggressive traffic enforcement; field interviews; street- level drug enforcement; follow-up investigation of arrestees; case- building | Weiss and McGarrell (1999) | Yes, reduced burglary in three out of four districts; reduced robbery in one out of four; reduced auto theft in all four (by 43%, 50%, and 53% in three districts), while the citywide crime rate was climbing | ||
| All crimes | Kansas City, Missouri | 1974 | Preventive Patrol Experiment | Random preventive patrol | Kelling et al. (1974) | No | No | |
| All crimes | Nashville, Tennessee | 1974-75 | Saturation patrol (four times the normal level, and 30 times the normal level of "slow patrol") | Schnelle et al. (1977) | Yes, reduced nighttime, but not daytime, burglary; concluded that the crackdown was not cost-effective | No spatial displacement | ||
| All crimes (specially intended to reduce crimes considered suppressible: burglary; street and commercial robbery; assault; auto theft; thefts from yards, autos, or buildings; DUI; possession of stolen property or weapons; and disorderly conduct) | Savannah, Georgia | 1998 | Aggressive traffic enforcement, especially of speeding, signal violations, seat belt violations, DUI, and license and registration violations; from 140% to 430% increase above normal levels | Josi, Donahue, and Magnus (2000) | Mixed results: there were significant reductions in Part I crimes (mainly burglary and larceny) in three out of four target areas, but there was less evidence of a significant impact on assaults and Part II offenses | |||
| All crimes and calls for service | Kansas City, Missouri | 1991-92 | Crack House Police Raids Program | Drug warrant raids | Sherman and Rogan (1995) | Yes, but the effect was modest; concluded the crackdown was not cost- effective | Yes, some spatial displacement | |
| All crimes and citizen fear | New York City (subways) | 1984 | Subway patrol by Guardian Angels (private patrol force) | Kenney (1986) | No, but there was a short-term reduction in citizen fear | |||
| All UCR Index offenses | Houston, Texas | 1994-96 | Targeted Beat Program | Overtime to put 655 additional officers in the seven highest crime beats in the city; high-visibility patrol; hot-spot monitoring; zero tolerance; problem-oriented approaches | Caeti (1999) | Yes, there were significant reductions in UCR Index crimes | No displacement; some diffusion of benefits to adjacent areas | |
| Assault, malicious damage to property, and offensive conduct | Sydney, Australia | 1992 | Regular but unpredictable visits to licensed premises to check for breaches of licensing laws | Burns and Coumarelos (1993) [Full text] | No | |||
| Burglary | United Kingdom | 1995 | Operation Christmas Cracker | Raids; arrests of burglary suspects; seizure of stolen property | Wright and Pease (1997) | There was no mention of an evaluation | ||
| Burglary (residential) | West Yorkshire, England (Boggart Hill area) | 1995 | Targeted and intensive enforcement against known burglars, followed by repeat victimization reduction efforts (target hardening, educating elderly potential victims of burglary by deception) and youth outreach programs | Farrell, Chenery, and Pease (1998) | Yes, there was a significant reduction in burglary and repeat victimization | No evidence of spatial displacement; some evidence of diffusion of benefits to other types of crime (auto theft) | ||
| Disorder-related calls for service | Minneapolis, Minnesota | 1988-89 | Hot Spots Patrol Program | Intense intermittent patrol at known hot spots (100% increase in patrol time at hot spots) | Sherman and Weisburd (1995) | Yes, there was a modest effect (25% less disorder at hot spots) | ||
| Drug hot spots | Jersey City, New Jersey | c. 1992 | Drug Markets Analysis Program | Identification and analysis of drug hot spots; engagement of business owners and citizens in crime control efforts; increased pressure on open-air markets (through drug enforcement, code enforcement, license regulation), maintained by patrol | Weisburd and Green (1995) | Yes, there were consistent and strong impacts in reducing disorder-related emergency calls for service, but there was no impact on violent or property offenses | No evidence of displacement; some evidence of diffusion of benefits to adjacent areas | |
| Gang-related violence | Dallas, Texas | 1996-97 | Enforcement of truancy and curfew laws; high- visibility patrol, with lots of stops and frisks by six to eight officers in areas where gangs hung out | Fritsch, Caeti, and Taylor (1999) | Yes, there were significant reductions in gang violence | No, minimal evidence of displacement | ||
| Gun-related crime | Indianapolis, Indiana | 1997 | Directed Patrol Project | Two alternative interventions: 1) increased traffic enforcement on major arteries, with lots of stops of limited duration (general deterrence strategy); 2) traffic stops of suspected gang members and drug dealers, of longer duration, with more investigation and vehicle searches | Weiss and McGarrell (1999) | Yes, the second intervention tactic resulted in significant reductions in gun-related crimes, aggravated assault, and homicide; there were no similar reductions resulting from the first intervention tactic | Little evidence of displacement; no evidence of geographic diffusion of benefits; modest evidence of residual deterrence effects 90 days after intervention | No, evidence of high level of public support both before and after intervention |
| Gun-related violence | Kansas City, Missouri | 1992-93 | Gun Project | Intensive enforcement of gun- carrying laws (Terry stops, searches incident to arrest, car stops and searches, plain-view searches,); door-to-door solicitation of tips; police training to interpret gun-carrying cues; field interviews in known gun crime hot spots | Sherman, Shaw, and Rogan (1995) | Yes, there was a 49% reduction in gun crimes in the target area during the intervention period, compared with the prior 29-week period; there were declines in both drive-by shootings and homicides; there was no apparent effect on total calls for service, other violence calls, property offenses, or disorder; the community became less fearful of crime and more satisfied with the neighborhood | Yes, modest spatial displacement; some evidence of diffusion of benefits to two adjoining beats | No |
| Gun-related crime | Pittsburgh, Pennsylvania | 1998 | Firearm Suppression Patrol Program | Extra dedicated police patrols on high-crime days of week and times of day for 14 weeks; traffic and pedestrian stops and searches; targeting of hot spots and times based on crime analysis | Cohen and Ludwig (2002) [Full text] | Yes, reduced shots fired by 34% and hospital-treated assault gunshot injuries by 71% | No evidence of temporal or spatial displacement; residual deterrence effects lasted about two weeks | No, no reported citizen complaints against police |
| Marijuana cultivation | Kentucky | 1982-87 | Locating, cutting down, and burning marijuana plants; asset seizure and forfeiture; drug enforcement | Potter, Gaines, and Holbrook (1990) | No (but the methodology limited the findings) | Yes | ||
| Public disorder (street cruising, loud music, and public drinking) | Anonymous jurisdiction | 1992 | Liquor license agents issued citations for open containers and other alcohol violations; local police parked police cars at intersections to monitor cruising; lasted for one month in 10-by-12- block area; no media publicity | Novak et al. (1999) | No (but the methodology limited the findings) | |||
| Robbery | New York City (subways) | 1965 | Extra police patrols put on subways from 8 PM to 4 AM ; nearly every station and train had a uniformed officer on duty; total transit system police force increased by 250% | Chaiken, Lawless, and Stevenson (1974) | Yes, minor offenses and felonies declined significantly due to increased patrol, but at substantial extra cost (about $35,000 per felony crime prevented); there was some question as to whether police reporting procedures accounted for some of the claimed reduction | No displacement; residual deterrence effects for eight months | ||
| Robbery, burglary, grand theft, petty theft, auto theft, assault/ battery, sex crimes, and malicious mischief/ disturbances | San Diego, California | 1973 | Field Interrogation Project | Field interrogations | Boydstun (1975) | Yes (there was some evidence that burglary, petty theft, and malicious mischief/disturbances are the most suppressible) | Inconclusive | No |
| Speeding | Connecticut | 1955 | Stiffer sanctions for speeding convictions: 30-day license suspensions for first offense, 60 for second, indefinite for third | Campbell and Ross (1968) | Not definitive; the overall conclusion was that the crackdown was a substantial enforcement effort, but some of its effects were mitigated in practice | |||
| Speeding and other traffic problems, crime, and disorder and blight | Charlotte, North Carolina | 1997 | Saturation patrol by about 30 officers/agents from various agencies; about 10 times the normal level of police activity in the area; traffic unit focused on traffic problems; alcohol agents worked bars; sheriff's deputies supervised inmates doing community service; traffic arrests increased tenfold; police made highly visible arrests in well-traveled parking lot at major intersection | Priest and Carter (2002) | Yes, there was some evidence of a modest effect on reported crime; unable to measure the effect on traffic crashes (weak evaluation) | |||
| Street drug markets | Richmond, Virginia | 1999 | Blitz to Bloom | Regular patrol supplemented by specialized units (10 times the normal level); field interviews; citations; surveillance; arrest of street drug dealers and buyers; high-visibility presence (including setting up a mobile police command post); code enforcement; cleanup; public works repairs; trimming of foliage | Smith (2001) | Yes, total reported Part I offenses and violent crime declined significantly (by 92%) during the crackdown period and rates were unchanged in the comparison area; Part I property crimes and calls for service declined, but not significantly | No spatial displacement of crimes, but significant displacement of calls for service to adjacent areas; some evidence of diffusion of benefits to adjacent areas; residual deterrence effects lasted about six months | |
| Street drug markets | New York City | 1988-90 | Tactical Narcotics Teams (TNTs) | Buy-busts and high police visibility in hot spots with high mobility; vehicle seizures and confiscations; initial crackdown operation never lasted longer than 90 days in an area, but maintenance crackdowns occurred as necessary; initiative claimed to incorporate community involvement and interagency collaboration to address drug market conditions, but there is little evidence this occurred | Smith et al. (1992) | There was a limited impact; there was an immediate benefit, but conditions returned to normal soon after the TNTs left; there were no measurable effects on public perceptions of crime, quality of life, or police-community relations; there was some increase in fear because drug dealing moved indoors to apartment hallways; there were some positive effects in making drug markets less visible in the target blocks | Yes, some displacement to indoor locations | No, some evidence community was largely unaware of crackdown in their neighbor-hood; community leaders generally supportive of crackdown |
| Street drug markets | New York City ( Lower East Side ) | 1984-86 | Operation Pressure Point (two smaller Pressure Point operations conducted in subsequent years) | 240 uniformed officers on foot patrol to disperse crowds; increased arrests; field interviews; warnings and parking tickets; searches; mounted park patrols; canine units to clear buildings; surveillance and buy-busts; anonymous tip lines; raids on dealing locations; asset forfeiture; increased likelihood of conviction and severity of sentences; custodial arrests made instead of citing and releasing; additional responses to address environmental conditions | Zimmer (1990) ; Kleiman (1988) | Yes, the search time for drugs increased; there was a reduction in heroin-related street activity; there were reductions in selected crime rates: burglary (37%), robbery (47%), grand larceny (32%), and homicide (62%); the neighborhood was revitalized; there was an increased demand for drug treatment | Mixed evidence: one study reported no spatial displacement, another reported displacement to other areas in and around city; some evidence of diffusion of benefits to adjacent areas | No, community support levels were high |
| Street drug markets | Tampa, Florida | 1989-91 | Quick Uniform Attack on Drugs (QUAD) | Observation by four 10-officer teams; arrests for drug dealing, public drinking, etc. (by special unit and patrol officers); short-term undercover work and buy-busts; reverse stings; vehicle seizures; use of confidential informants; code enforcement; neighborhood cleanups; demolition of abandoned buildings; heavy media coverage; visible response to every citizen complaint; encouragement of anonymous complaints, with promises to protect complainants' identities; mobile booking stations to speed up arrests; parked marked units in middle of drug markets; uniformed patrol through the markets; removal of shade covering dealers; use of expedited nuisance abatement procedures; provision of police beeper numbers to citizens so they could feel more assured of anonymity; confiscation of stashed drugs from citizen tips; arrests for loitering for the purpose of drug dealing (and conspicuously posted warning signs); trespass authority arrests | Kennedy (1993) [Full text] | Yes, visible drug dealing declined significantly, but the study was unable to determine which particular tactics were the most effective; there was some evidence of declines in overall crimes, calls for service, and drug-related homicides | Yes, some displacement to indoor locations | No, evidence of high level of community support from both majority and minority communities |
| Street drug markets | Washington, D.C. | 1988 | Operation Clean Sweep | High-volume arrests for drug dealing and other offenses | Reuter et al. (1988) | No, but there was some evidence that the overall crime rate declined, and the study concluded that local drug crackdowns were worthwhile | ||
| Street drug markets | Houston, Texas | 1988 | Link Valley Drug Sweep | 100 officers conducted buy-busts; checkpoints established; door-to-door searches of residences; media publicity; neighborhood cleanups; code enforcement | Kessler and Duncan (1996) | No, there were no significant reductions in overall crime, calls for service, or drug-related crime | ||
| Street drug markets (crack) | Oakland, California | 1988-89 | Special Duty Unit 3 | Intensive drug enforcement through high- visibility patrol (stopping, questioning, and frisking motorists, bicyclists, and pedestrians); buy-busts (targeted in hot spots); crack house raids; compared with door-to-door interviews with residents to discuss drug problems and a drug hotline | Uchida, Forst, and Annan (1992) | Mixed results: there was some positive effect on violent crimes but not on burglary and robbery; there were positive effects on citizen perceptions of safety, drug dealing, and police services | Yes, evidence of spatial displacement, but police shifted crackdown to new areas | No |
| Street drug markets (heroin) | Lawrence, Massachusetts | 1984 | Lawrence Drug Task Force | Surveillance; informants; informant buys; buy-busts; anonymous drug tip line | Kleiman (1988) | No, there was some evidence of suppression of the heroin market in one location, but the overall effect on markets and crime was limited | Yes, some evidence drug buyers easily shifted to drug market in nearby city | |
| Street drug markets (heroin) | Lynn, Massachusetts | 1983-84 | Lynn Drug Task Force | Four to six narcotics officers surveilled known drug-dealing locations, questioned buyers and sellers, made arrests for possession, used informants for buy-bust arrests, and executed search warrants on drug houses; hotline for anonymous tips was established and publicized | Kleiman (1988) | Yes, there was a significant decrease in the volume and flagrancy of the retail heroin market; there was some evidence that heroin use declined; there was an 85% increase in the demand for drug treatment; reported robberies declined by 18.5%, burglaries by 37.5%, and crimes against the person by 66% | Unknown if there was displacement to other types of drugs; one year after the crackdown, burglaries stayed down and robberies continued to decline | No, high citizen satisfaction with results |
| Street drug markets (heroin) | Maribyrnong, Australia | 2000 | Operation Clean Heart | Field interviews; high-visibility patrol | Aitken et al. (2002) [Full text] | Yes, but at a high social cost | Yes | Yes |
| Street drug markets (heroin) | Sydney, Australia | 1995-97; 2001 | Buy-busts of dealers and users | Maher and Dixon (2001) [Full text] | The study acknowledges some success in disrupting street drug markets, but it focused more on the negative consequences of crackdowns | Yes, some spatial displacement to indoor locations and other neighbor-hoods | ||
| Street drug markets (heroin, crack, marijuana) | London | 2000 | Operation Crackdown | Arrests; drug seizures | Best et al. (2001) [Abstract only] | No | No | |
| Street drug markets (powder cocaine and Dilaudid) | Birmingham, Alabama | 1988 | Operation Caine Break | Intensive drug enforcement (buy-busts, reverse buys, vehicle forfeiture, media coverage of arrests), compared with two other responses: door-to-door surveys of residents about drug problems, and establishment of police substation | Uchida, Forst, and Annan (1992) | Mixed results: there was no measurable reduction in drug trafficking, but there were positive effects on citizen perceptions of police and crime problems; there were some measurable crime reductions | No | |
| Street drug markets (powder cocaine) | Hartford, Connecticut | 1990 | COMPASS | Street-level drug enforcement (undercover drug buys, search warrants, buy-busts, reverse stings, surveillance arrests, vehicle safety checks), followed by community revitalization | Caulkins, Larson, and Rich (1993) | There was some evidence of effectiveness; there was a dramatic decrease in drive-by shootings; the study concludes that geo-graphically contained areas are more favorable for crackdowns | No | No |
| Street prostitution | London | 1983-86 | Intensive enforcement against prostitutes, clients, pimps, and brothel operators, combined with road closures | Matthews (1997) [Full text] | Yes, prostitution and serious crime declined significantly; the sense of public safety increased; crime reporting rates increased | No evidence of spatial displacement | No, actually improved police-community relations | |
| Street prostitution | New York City (Midtown Manhattan ) | 1993 | Intensive enforcement of low-level offenses by patrol officers, combined with sanctions of the Midtown Community Court | Weidner (1999) | Yes, the incidence and prevalence of street prostitution significantly declined; some stroll areas disappeared almost entirely; there was little evidence that many prostitutes quit the trade, however | Yes, evidence of spatial displacement to outer boroughs; evidence of target, method (prostitutes switched from walking to driving around), and temporal displacement | ||
| Street prostitution | New York City ( Times Square ) | 1983 | Operation Weekend | Arrest sweeps | Eckart (1984) | No impact evaluation was reported | ||
| Street prostitution | Newport News, Virginia | 1984 | Variety of responses in a problem-oriented policing project, including arrests of prostitutes | Eck and Spelman (1987) | Yes, there was a significant reduction in the number of street prostitutes and prostitution-related robberies | No | ||
| Traffic crashes | Nashville, Tennessee | 1978 | Intensive traffic enforcement (compared with normal and below- normal levels) | Carr, Schnelle, and Kirchner (1980) | No | |||
| Violent crime at targeted locations | Jersey City, New Jersey | 1994 | POP at Violent Places Project | Variety of responses (28 different ones); aggressive order maintenance | Braga et al. (1999) | Yes | Some spatial displacement of property crimes, but most crimes and calls for service not displaced |
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The Benefits and Consequences of Police Crackdowns
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