Program Profile: Kansas City (MO) Gun Experiment

This program consisted of a police patrol experiment, which was designed to reduce gun violence in Kansas City (Mo.) by placing extra police patrols in gun crime hot spots. The program is rated Promising. In the treatment area, there was a statistically significant increase in gun seizures and a statistically significant decrease in gun crimes, compared with the comparison area, in the 6 months following implementation.

A Promising rating implies that implementing the program may result in the intended outcome(s).

Program Goals

The Kansas City (MO) Gun Experiment was a police patrol project that was aimed at reducing gun violence, drive-by shootings, and homicides. For 29 weeks during 1992–93, the Kansas City Police Department (KCPD) focused extra police patrols in gun crime “hot spots” in a targeted area of the city. Extra patrol was provided in rotation by officers from the Central Patrol Division in a pair of two-officer cars. The officers on overtime worked from 7 p.m. to 1 a.m., 7 days a week. They were asked to concentrate on gun detection through proactive patrol, and they were not required to answer other calls for service.

Target Site

The target site, or treatment area, in the gun experiment was patrol beat 144 in the Central Patrol District of Kansas City, MO. The site had the second-highest number of drive-by shootings of any patrol beat in 1991. The target beat was in an 80-by-10-block area that had a homicide rate of 177 per 100,000 persons, almost 20 times the national average (Sherman, Shaw, and Rogan 1995).

Program Theory

The Kansas City Gun Experiment was based on the hypothesis that gun seizures and gun crime are inversely related. In other words, as gun seizures increase, gun crime should decrease. There are two possible mechanisms that can explain this relationship: deterrence and incapacitation. Deterrence theory hypothesizes that if it were to become known that law enforcement is likely to seize guns, illegal gun carriers would be less likely to carry guns in the area. Deterrence theory also suggests that increasing patrol visibility in the area will generally deter all crime. The incapacitation theory suggests that if guns were confiscated from enough potential gun criminals in the area, the criminals would be unable to commit gun crimes (incapacitated)—at least for the time until they obtained a new gun (Sherman and Rogan 1995).

Program Components

The gun experiment was first developed in 1991 from funding provided by the U.S. Department of Justice under the “Weed and Seed” program. The police and academic team that designed the experiment chose the reduction of gun crime as the principal objective of the program because the area had the second-highest number of drive-by shootings of any patrol beat citywide. The federal funds allowed for extra police patrol and overtime.

The KCPD actually implemented three different strategies for increasing gun seizures in beat 144: 1) door-to-door solicitation of anonymous tips; 2) training police to interpret gun-carrying cues in body language; and 3) field interrogations in gun crime hot spots. The extra police patrol in hot spots areas was associated entirely with the third strategy.

The actual techniques used by the officers to locate guns varied widely. They included searches of individuals under arrest on charges other than gun crimes, plain-view searches of cars, and safety frisks of individuals who had been stopped in their cars for traffic violations. The following examples illustrate some of the methods used by officers to seize guns:

• Safety frisk during traffic stop: after pulling someone over for a traffic violation, the officers asked the driver for his/her license. When the driver would lean over to the glove compartment, a bulge may be revealed under the jacket of the left arm. The officer would grab the bulge, feel a hard bulk in the shape of a gun, and reach into the jacket to pull the gun out.
• Plain view: as an officer approached the car they had pulled over for a traffic violation, the officer would shine a flashlight onto the floor in the front of the back seat and see a shotgun. After ordering the driver and any passengers out of the car, the officer finds that the shotgun is loaded.
• Search incident to arrest on other charges: after pulling someone over for a traffic violation, the officers asked the driver for his/her license. A computer check reveals that the diver is wanted for a failure to appear on domestic assault charges. The officer would arrest the driver, conduct a search, and find a gun hidden inside the suspect's shirt.

The following is a breakdown of the methods used by the patrol officers to seize guns during the experimental period: 21 percent plain view, 34 percent frisk for safety, and 45 percent search upon arrest.

Additional Information

Some questions may be asked about the methods used by police officers, and often critics of these procedures voice concerns about the rate of false positives and the potential discrimination entailed in responding to certain patterns of situational cues. The U.S. Supreme Court has ruled on the issue of safety frisks in Terry v. Ohio 1968, which allows officers to pat down the outside of the suspect’s clothing to check for guns. However, the Supreme Court has not attempted to articulate the substantive basis for police officers’ suspicions. The court places on the officers the responsibility of articulating a reasonable basis for frisking an individual but implicitly accepts the facts cited by police as reasonable (Sherman, Shaw, and Rogan 1995).

Study 1

Sherman and Rogan (1995) used a quasi-experimental design to study the effectiveness of the Kansas City (Mo.) Gun Experiment. The treatment area, beat 144 (described above in Program Description), had high rates of violent crime, including driveby shootings and homicides. The comparison area, patrol beat 242 in the Metro Patrol District, was selected because of the almost-identical number of driveby shootings. The treatment area had a population of 4,528 persons, who were 53 percent female, were 92 percent nonwhite, and had a median age of 32 years. The comparison area had a population of 8,142 persons, who were 56 percent female, were 85 percent nonwhite, and had a median age of 31 years. The comparison area was slightly different from the treatment area. Aside from the higher population, the comparison area had three times the land area and had slightly higher housing prices.

Extra patrol attention on gun crime “hot spots” was provided by the Kansas City Police Department from July 7, 1992, through Jan. 27, 1993. The hot spots locations were identified by computer analysis of all gun crimes in the area. Gun crime was defined as any offense report in which the use of a gun by the person committing the crime is mentioned. Officers in the treatment area worked a total of 200 nights, 4,512 officer-hours, and 2,256 patrol car-hours. In the comparison area, no special efforts were made to limit police activities, but there were no funds available for extra patrol time.

The primary measure of interest was gun crime. The extra patrol hours were federally funded; therefore, separate booking was required to document the time. In addition, evaluators accompanied the officers on 300 hours of hot spots patrol and coded every shift activity narrative for patrol time and enforcement inside and outside of the area. Property room data on guns seized, crime reports, data on calls for service, and arrest records were all analyzed for the treatment and comparison areas. Gun crimes were counted according to offense records showing that a gun had been used in the crime.

The data were analyzed using four different models. The primary analyses assumed that the gun crime counts were independently sampled from the patrol beats examined before and after the intervention. This model treated the before–during different in the mean weekly rates of gun crime as an estimate of the magnitude of the effect of the hot spots patrols, and assessed the statistical significance of the differences with the standard two-tailed t–tests. A second model assumed that the weekly gun crime data points were not independent but were correlated serially, and thus required a Box–Jenkins ARIM (autoregressive integrated moving average) test of the effect of an abrupt intervention in a time series. A third model examined rate events (homicide and driveby shootings) aggregated in 6-month totals on the assumption that those counts were independent, using one-way analysis of variance (ANOVA) tests. A fourth model also assumed independence of observations, and compared the treatment with the control beat in a before–during chi-square test.

The t–tests compared weekly gun crimes for all 29 weeks of the phase 1 patrol program (July 7, 1992, through Jan. 25, 1993) with the 29 weeks preceding phase 1, using difference-of-means tests. The ARIM models extended the weekly counts to a full 52 weeks before and after the beginning of phase 1. The ANOVA model added another year before phase 1 (all of 1991) as well as 1993, the year after phase 1. Additional analyses were conducted to examine the displacement of crime in seven patrol beats surrounding the treatment area.

Diffusion and Displacement

Sherman and Rogan (1995) conducted additional analyses to examine the displacement of crime in seven patrol beats surrounding the treatment area that implemented the Kansas City (Mo.) Gun Experiment. They found no statistically significant increase in gun crimes in the surrounding areas, suggesting no displacement.

These sources were used in the development of the program profile:

These sources were used in the development of the program profile:

Following are CrimeSolutions-rated programs that are related to this practice:

Hot Spots Policing

Hot spots policing strategies focus on small geographic areas or places, usually in urban settings, where crime is concentrated. Through hot spots policing strategies, law enforcement agencies can focus limited resources in areas where crime is most likely to occur. This practice is rated Effective for reducing overall crime and rated Promising for reducing violent, property, public order, and drug and alcohol offenses.

Evidence Ratings for Outcomes

	Crime & Delinquency - Multiple crime/offense types
	Crime & Delinquency - Violent offenses
	Crime & Delinquency - Property offenses
	Crime & Delinquency - Public order offenses
	Crime & Delinquency - Drug and alcohol offenses

Reducing Gun Violence

Reducing gun violence is a persistent public policy concern for communities, policymakers and leaders. To reduce gun violence, several strategies have been deployed including public health approaches (e.g., training and safe gun storage); gun buy-back programs; gun laws; and law enforcement strategies. The practice is rated Promising for reducing violent gun offenses.

Evidence Ratings for Outcomes

Crime & Delinquency - Violent offenses

Geographically Focused Policing Initiatives

Geographically focused policing initiatives increase the presence and visibility of police officers at specific high-crime locations to significantly reduce crime and disorder. This practice is rated Promising for reducing crime in treatment areas relative to control areas.

Evidence Ratings for Outcomes

Crime & Delinquency - Multiple crime/offense types

Police-Initiated Pedestrian Stops to Reduce Crime

Police-initiated pedestrian stops involve police officers’ stopping, questioning, and investigating pedestrians on the street, usually based on suspicion of criminal behavior or activity. Generally, the goal of the stops is to prevent or reduce the occurrence of crime and disorder. The practice is rated Promising for reducing measures of crime and displacement but was rated No Effects for improving measures of mental and physical health of citizens who were stopped by police.

Evidence Ratings for Outcomes

	Crime & Delinquency - Multiple crime/offense types
	Crime & Delinquency - Displacement effects
	Mental Health & Behavioral Health - Multiple mental health/behavioral health outcomes
	Physical Health - Physical health of citizens who come into contact with law enforcement

Why might a practice's outcome ratings differ from the ratings of specific programs encompassed by that practice?