This crime hot spots intervention was conducted in Sacramento, California, by the Sacramento Police Department (SPD). The intervention was designed to: 1) better ensure that police service to the community was delivered as intended by providing clearer guidelines on how police officers should patrol, and 2) minimize boredom and maximize the effectiveness of police officers via a deployment strategy in which officers would not spend long periods in the same place. The goal was to reduce crime in the city. As of 2010, the Sacramento Metropolitan area had a population of over 2.1 million; the 24th largest in the United States and the 4th largest in California. Per the 2010 Uniform Crime Reporting Data, the city’s violent and property crime rates were above the national average, yet both rates had declined, compared with the prior 5 years. At the end of 2010, SPD had 707 sworn officers eligible for assignment to patrol duties.
Sherman and Weisburd (1995) found that targeted increase in police presence leads to some crime and disorder reduction. In addition, Koper (1995) found that the ideal time spent in a hot spot was 14 to15 minutes; after about 15 minutes, there were diminished deterrent effects, and the increased time did not create more residual deterrence. Known as the “Koper Curve,” this theory promotes an approach where police travel between hot spots, spending about 15 minutes in each hot spot, and move from hot spot to hot spot in an unpredictable order to increase the perception of the costs of offending in those areas. This intervention was designed to test Koper’s (1995) conclusions about the most effective and efficient police patrol strategy at hot spots.
The intervention specifically targeted areas in Sacramento that suffered from high levels of citizen-generated calls for service and crime incidents: District 3 (downtown and midtown areas as well as the campus of California State University, Sacramento) and District 6 (the southeastern part of the city and the neighborhoods of Oak Park and Tahoe Park).
SPD officers were assigned to one to six hot spots in their patrol areas and were given a random order, which shifted daily and varied by shift, to visit their assigned hot spots. The officers were instructed to visit their assigned hot spots for 12 to16 minutes per the order provided by their unit sergeant, and to treat each hot spot in their patrol areas once every 2 hours. A special call sign was used for the intervention, and officers were directed to initiate a call with radio code (D1HOT) when present in their assigned hot spots.
While officers were not given specific instructions on what to do in each hot spot, they did receive daily recommendations through their in-car computers to engage in proactive activities such as traffic stops, street checks, and citizen contact. SPD’s crime analysis unit tracked the officers’ movements with the department’s automated vehicle locater (AVL) system to validate that officers were present in hot spots when the radio code was initiated and that intervention protocols were used.
Part I Crime Incidents (2010 versus 2011)
When comparing the number of Part I crime incidents during the experimental period (90 days in 2011) with the same period in 2010, Telep, Mitchell, and Weisburd (2012) found statistically significant declines in treatment hot spots, compared with control hot spots.
Part I Crime Incidents (2008–2010 versus 2011)
When comparing the average number of Part I crime incidents during the experimental period (90 days in 2011) with the average number of Part I crime incidents between 2008 to 2010, there were no statistically significant differences between the treatment hot spots and control hot spots.
Soft Crime Incidents (2010 versus 2011)
When comparing the average number of soft crime incidents during the experimental period (90 days in 2011) with the same period in 2010, there were no statistically significant differences between the treatment hot spots and control hot spots.
Soft Crime Incidents (2008–2010 versus 2011)
When comparing the average number of soft crime incidents during the experimental period (90 days in 2011) with the average number of soft crime incidents between 2008 to 2010, there were no statistically significant differences between the treatment hot spots and control hot spots.
Calls for Service (2010 versus 2011)
When comparing the average number of calls for service during the experimental period (90 days in 2011) with the same period in 2010, there was a statistically significant decline in the treatment hot spots, compared with the control hot spots. Each treatment hot spot had an average decline of 3.57 calls for service, while each control hot spot had an average increase of 4.42 calls.
Calls for Service (2008–2010 versus 2011)
When comparing the average number of calls for service during the experimental period (90 days in 2011) with the average number of calls for service between 2008 to 2010, there was a statistically significant decline in calls for service in the treatment hot spots, compared with the control hot spots. Each treatment hot spot had an average decline of 5.51 calls for service, while each control hot spot had an average increase of 2.11 calls.
Telep, Mitchell, and Weisburd (2012) conducted a randomized controlled trial to evaluate if officers who randomly moved from hot spot to hot spot and spent about 15 minutes in each area had a significant impact on crime incidents and calls for service, when compared with standard police patrol. In the planning phase, the Sacramento Police Department (SPD) identified all citizen-generated calls for service for District 3 and District 6 from January 2009 to December 2010. SPD excluded the following from the sample: 1) all non-crime related calls, 2) calls geocoded to an intersection to create hot spots that were a street block in length, and 3) calls to certain high-call addresses that did not qualify as typical hot spots such as hospitals and the county courthouse. A total of 119,480 geocoded calls from District 3 and District 6 remained in the sample, but the department looked at the top 40 hot spots based on calls for service. For Part I crimes, all 2010 incidents were examined, and after intersection data and ineligible addresses were removed, a total of 7,479 incidents remained in the sample. The same criteria as calls for services were used, street segments were ranked, and the top 25 hot spots for Part I crimes not identified from the top 40 calls for service were added. The top 20 hot spots for soft crime incidents were assessed and removed from the sample as they did not correlate highly with the calls for service and Part I crime hot spots.
After initial assessment, 52 hot spots were identified for further review. Two officers physically observed these areas to confirm that the hot spots were suitable for the experiment. Inclusion criteria at this stage included that no hot spot 1) was larger than one standard linear street block, 2) extended for more than one half block from either side of an intersection, and 3) was within one standard linear block of another hot spot. Based on officer observations and the inclusion criteria, 42 hot spots were included in the experiment. To reduce variability between the 21 treatment hot spots (that received the intervention) and 21 control hot spots (that received standard police patrol), the hot spots were paired prior to randomization based upon similarity in levels of calls for service, crime incidents, and similar physical appearance based on the initial observations. After pairing, a computerized random-number generator assigned hot spots to either the treatment or control groups. Sixteen of the treatment group hot spots were in District 3, and five were in District 6.
The intervention was implemented in Sacramento, Calif., a large urban city, from February 8, 2011 to May 8, 2011, 7 days a week, between the hours of 9:00 a.m. and 1:00 a.m. As part of this 90-day experiment, SPD officers were assigned to one to six hot spots in their patrol areas and were given a random order, which shifted daily and varied by shift, to visit their assigned hot spots. Officers were not informed about which areas were designated as treatment or control hot spots. Each week, 10 percent of officer-initiated calls in the treatment area were randomly chosen and compared with AVL data to determine whether officers were present in their hot spots for the same amount of time that their call logs indicated. Analyses suggested that officers complied with the experimental protocols, were always physically present in the treatment hot spots, and spent 12 to 16 minutes at a time in hot spots. The dosage levels of police presence were approximately 546 visits a week, with the lowest treatment week being 432 and the highest 698. In general, there were 7.095 visits (averaged 78.8 visits per day) to 21 treatment group hot spots during the experiment; the total number of visits at each individual hot spot ranged from 223 to 559 visits. In total, 2,875 hours were spent on calls in the treatment hot spots versus 1,014 hours in the control hot spots.
The study examined three outcomes: 1) citizen-generated emergency calls for service to 911, per SPD police databases; 2) Part I crime incidents based on the Uniform Crime Report classification of serious crimes (e.g., robbery, burglary, auto theft, and aggravated assault); and 3) soft crime incidents or less serious criminal incidents related to disorder (public drunkenness, trespassing, and vandalism). A difference-in-differences analysis was used to examine whether treatment hot spots showed changes between years that were different from the changes in the control hot spots. Analyses compared the following two periods: the experimental year (90 days in 2011) with the same period in 2010, and the experimental year with an average of the pre-experimental years (2008 to 2010). Due to the randomization process, any difference between groups was attributed to the police hot spots intervention.
One limitation to the study was that the study authors were unable to evaluate the efficacy of officer tactics while in the treatment group hot spots and could only draw conclusions about the effectiveness of the random 15-minute stops in the hot spot, compared with the standard police patrol.
There is no cost information available for this program.
While results suggested statistically significant declines in calls for service and Part I crime incidents in treatment hot spots, sensitivity analyses indicated that these declines were not consistent across all hot spots. Every single treatment hot spot showed either a decline in at least one outcome between 2010 and 2011 or an improvement in calls for service or incidents, compared with the control hot spots. However, 4 of the 21 treatment hot spots did not perform better than the control group in at least one of the two outcomes. Thus, the intervention was not universally effective across all 21 treatment hot spots (Telep, Mitchell, and Weisburd 2012).
Telep, Mitchell, and Weisburd (2012) also assessed several other outcomes, including 1) response time, 2) crime displacement, and 3) officer proactivity. In District 3, where most of the study’s hot spots were located, the average response time decreased, when comparing the experimental period with the same period in 2010. In District 6, the average response time increased; however, these changes were minimal and were still higher than the average response time for other districts in the city. In terms of crime displacement, there were changes in calls for service and Part I incidents in the two-block catchment areas surrounding treatment and control hot spots, but these changes were not statistically significant. When examining officer proactivity, excluding calls directly related to experimental protocols, the study authors found that both District 3 and 6 showed increases in officer-initiated activity, which suggested that officers did not remain in their patrol cars, but were engaged in a great deal of proactivity in the treatment areas.
Evidence-Base (Studies Reviewed)
These sources were used in the development of the program profile:Study 1
Telep, Cody W., Renée J. Mitchell, and David Weisburd. 2014. “How Much Time Should the Police Spend at Crime Hot Spots? Answers from a Police Agency Directed Randomized Field Trial in Sacramento, California.” Justice Quarterly
These sources were used in the development of the program profile:
Koper, Christopher S. 1995. "Just Enough Police Presence: Reducing Crime and Disorderly Behavior by Optimizing Patrol Time in Crime Hot Spots." Justice Quarterly
Sherman, Lawrence W., and David Weisburd. 1995. "General Deterrent Effects of Police Patrol in Crime ’Hot Spots’: A Randomized, Controlled Trial." Justice Quarterly
Following are CrimeSolutions.gov-rated practices that are related to this program:Hot Spots Policing
Used by many U.S. police departments, hot spots policing strategies focus on small geographic areas or places, usually in urban settings, where crime is concentrated. The practice is rated Effective. The analysis suggests that hot spots policing efforts that rely on problem-oriented policing strategies generate larger crime reduction effects than those that apply traditional policing strategies in crime hot spots.Evidence Ratings for Outcomes:
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