What Explains the Effectiveness of Hot Spots Policing And What New Strategies Should we Employ? David Weisburd Executive Director Center for Evidence-Based Crime Policy George Mason 1
The Effectiveness of Hot Spots Policing Minneapolis Hot Spots Patrol Experiment 110 crime hot spots randomly allocated to treatment and control conditions. Treatment sites received between 2-3 times the preventive patrol as control sites. In a Campbell review Braga et al. (in press) identify 25 experimental and quasi experimental studies. 21 of 25 tests show statistically significant crime prevention benefits. National Research Council Committee to Review Research on Police Policy and Practices concluded: studies that focused police resources on crime hot spots provide the strongest collective evidence of police effectiveness that is now available (2004: 250). Sherman, Lawrence and David Weisburd. (1995). David Weisburd, General Deterrent George Effects Mason of Police Patrol in Crime Hot Spots : A Randomized Study. Justice Quarterly, 12(4), 625-648. 2
The Law of Crime Concentrations Focusing on Crime Hot Spots is Efficient! 3
1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Percentage of Total Street Segment Law of Crime Concentrations Over Time 60% 50% 100% of Crime 40% 30% 20% 10% 50% of Crime 0% Weisburd, David, Shawn Bushway, Cynthia Lum, and Sue-Ming Yang. (2004). Trajectories of Crime at Places: A Longitudinal Study of Street David Segments Weisburd, in the George City of Mason Seattle. Criminology, 42(2), 283-322. 4
Law of Crime Concentrations Across Cities: New York 2009 2010 n % n % Incidents in the Top 10% of the Street Segments 229,236 68.9 232,192 69.6 Incidents in the Top 5% of the Street Segments 173,591 52.2 175,571 52.6 Incidents in the Top 1% of the Street Segments 51,454 24.5 82,005 24.6 5
Crime Concentrations in Tel Aviv (Crime Incidents=31,550; Street Segments=17,160) 33.4% 35.0% 30.0% 25.0% 11.9% 20.0% 15.0% 1.3% 5.0% 10.0% 5.0% 25% 50% 75% 100% 0.0% 6
Crime Counts The Stability of Crime Concentrations at Crime Hot Spots (Weisburd, Bushway, Lum and Yang, 2004) 100 80 60 40 20 0 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Trajectory1(13.4%) Trajectory2(33.5%) Trajectory3(12.3%) Trajectory4(6.4%) Trajectory5(4.8%) Trajectory6(8.2%) Trajectory7(4.2%) Trajectory8(4.1%) Trajectory9(3.7%) Trajectory10(0.4%) Trajectory11(1.5%) Trajectory12(2.1%) David Weisburd, Trajectory13(1.0%) George Mason Trajectory14(1.2%) Trajectory15(0.5%) Trajectory16(1.0%) Trajectory17(0.9%) Trajectory18(0.7%) 7
Crime Hot Spots Not Bad Neighborhoods Focusing on Crime Hot Spots is the Right Geographic Level of Focus 8
Hot spots are Spread Throughout the City Landscape 9
The Variability of Crime Within Neighborhoods 10
Crime is Coupled to Place We Can Reduce the Risk Factors that Bind Crime to Place and Increase the Protective Factors that Prevent Crime at Place 11
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Crime Opportunities, Social Disorganization, and the Coupling of Crime to Place Crime and Place scholars have focused primarily on the situational opportunities that link crime to place. In our book we draw from community level crime prevention theories and ask whether social features of places also couple crime to place. We argue that hot spots are micro-communities as well as micro-places. 13
Social Features of Places Also Vary on a Micro Geographic Level 50 percent of housing assistance is consistently found on about 0.4 percent of the street segments in Seattle. Within 800 feet of the public assistance hot spots, 84.3 percent of street segments do not have any public housing assistance recipients. We used active voting on a street as a measure of collective efficacy (Sampson et al. 1997). When we examine the street segments within 800 feet of the hot spots of active voters (the top 10 percent), only 25% of neighboring street segments also evidenced such high levels of active voting. 14
The Predictability of Crime at Place Measure of Model Fit Value Chi-Square Full Model Cox and Snell 0.632 - Nagelkerke 0.684 - -2 Log Likelihood 61,870 24,000*** Multinomial Logistic Regression Measures of Model Fit (Weisburd, Groff, & Yang, 2012 ) 15
Most Important Predictors of Crime Hot Spots Variable* Odds Ratio Standardized Coefficient Employees 1.075*** 9.16162 Residents 1.241*** 5.87801 High Risk Juveniles 2.218*** 1.67532 Property value 0.704*** -1.26272 Physical Disorder 25.634*** 1.23021 Arterial Road 10.870*** 1.05545 Collective Efficacy.041*** -1.00986 n = 24,023; B = beginning value; C = change variable * p <.05, ** p <.01, *** p <.001 Cox and Snell Pseudo R 2 =.632; Nagelkerke Pseudo R 2 =.684 *Other street segment-level variables in the model: Percent of residents on housing assistance, number of truant juveniles, racial heterogeneity, urbanization, mixed land use, street segment length, bus stops, percent vacant land, street lighting, presence of police & fire stations, spatial lag variables, and eight variables related to changes over time. 16
Why Is Hot Spots Policing Effective? Law of crime concentrations. The correct level of focus (micro places!). Crime is coupled to place. Deterrence through increased police presence reduces the situational opportunities for crime at place. Police are guardians and they prevent motivated offenders from taking advantage of crime opportunities. 17
Opportunities for Social Prevention at Crime Hot Spots But our research suggests that crime is coupled to place not only by immediate situational opportunities but also by social factors. This raises the question of whether we can focus on increasing the social and economic capital of places as a way to decrease risk and increase protective factors related to crime. For example, our work suggests that if we were to increase the collective efficacy of residents of street segments we might be able to reduce crime in the long run. 18
The Importance of Focusing Social Interventions Social interventions are often seen as unrealistic in part because changing social conditions in neighborhoods and communities requires resources outside the scope of most crime prevention programs. Focus on crime hot spots provides an opportunity to lower the scale of social interventions, and accordingly to make such interventions relevant to crime prevention practitioners. We are now beginning to test the ability of police and communities to focus social interventions at crime hot spots. In Seattle we are working with the police and community groups to apply this approach to juvenile hot spots In Brooklyn Park, Minnesota we are proposing a study that would focus police patrol on increasing collective efficacy at crime hot spots. 19
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