Evaluation of the Shreveport Predictive Policing Experiment
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This electronic representation of RAND intellectual property is provided for non-commercial use only. Unauthorized posting of RAND electronic documents to a non-RAND website is prohibited. RAND electronic documents are protected under copyright law. Permission is required from RAND to reproduce, or reuse in another form, any of our research documents for commercial use. For information on reprint and linking permissions, please see RAND Permissions. This report is part of the RAND Corporation research report series. RAND reports present research findings and objective analysis that ad- dress the challenges facing the public and private sectors. All RAND reports undergo rigorous peer review to ensure high standards for re- search quality and objectivity. Evaluation of the Shreveport Predictive Policing Experiment Priscillia Hunt, Jessica Saunders, John S. Hollywood C O R P O R A T I O N Safety and Justice Program Evaluation of the Shreveport Predictive Policing Experiment Priscillia Hunt, Jessica Saunders, John S. Hollywood The research described in this report was sponsored by the National Institute of Justice and was conducted in the Safety and Justice Program within RAND Justice, Infrastructure, and Environment. This project was supported by Award No. 2009-IJ-CX-K114, awarded by the National Institute of Justice, Office of Justice Programs, U.S. Department of Justice. The opinions, findings, and conclusions or recommendations expressed in this publication are those of the authors and do not necessarily reflect those of the Department of Justice. Library of Congress Cataloging-in-Publication Data is available for this publication. ISBN: 978-0-8330-8691-4 The RAND Corporation is a nonprofit institution that helps improve policy and decisionmaking through research and analysis. 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RAND OFFICES SANTA MONICA, CA • WASHINGTON, DC PITTSBURGH, PA • NEW ORLEANS, LA • JACKSON, MS • BOSTON, MA CAMBRIDGE, UK • BRUSSELS, BE www.rand.org Preface Predictive policing is the application of statistical methods to identify likely targets for police intervention (the predictions) to prevent crimes or solve past crimes, fol- lowed by conducting interventions against those targets. The concept has been of high interest in recent years as evidenced by the growth of academic, policy, and editorial reports; however, there have been few formal evaluations of predictive policing efforts to date. In response, the National Institute of Justice (NIJ) funded the Shreveport Police Department (SPD) in Louisiana to conduct a predictive policing experiment in 2012. SPD staff developed and estimated a statistical model of the likelihood of property crimes occurring within block-sized areas. Then, using a blocked random- ized approach to identify treatment and control district pairs, districts assigned to the treatment group were given maps that highlighted blocks predicted to be at higher risk of property crime. These districts were also provided with overtime resources to conduct special operations. Control districts conducted property crime–related special operations using overtime resources as well, just targeting areas that had recently seen property crimes (hot spots). This study presents results of an evaluation of the processes in addition to the impacts and costs of the SPD predictive policing experiment. It should be of interest to those considering predictive policing and directed law enforcement systems and operations, and to analysts conducting experiments and evaluations of public safety strategies. This evaluation is part of a larger project funded by the NIJ, composed of two phases. Phase I focuses on the development and estimation of predictive models, and Phase II involves implementation of a prevention model using the predictive model. For Phase II, RAND is evaluating predictive policing strategies conducted by the SPD and the Chicago Police Department (contract #2009-IJ-CX-K114). This report is one product from Phase II. The RAND Safety and Justice Program The research reported here was conducted in the RAND Safety and Justice Program, which addresses all aspects of public safety and the criminal justice system, including iii iv Evaluation of the Shreveport Predictive Policing Experiment violence, policing, corrections, courts and criminal law, substance abuse, occupational safety, and public integrity. Program research is supported by government agencies, foundations, and the private sector. This program is part of RAND Justice, Infrastructure, and Environment, a divi- sion of the RAND Corporation dedicated to improving policy and decisionmaking in a wide range of policy domains, including civil and criminal justice, infrastructure protection and homeland security, transportation and energy policy, and environmen- tal and natural resource policy. Questions or comments about this report should be sent to the project leader, John Hollywood ([email protected]). For more information about the Safety and Justice Program, see http://www.rand.org/safety-justice or contact the director at sj@ rand.org. Contents Preface ................................................................................................iii Figures and Tables ................................................................................. vii Summary ............................................................................................. ix Acknowledgments .................................................................................xix Abbreviations .......................................................................................xxi CHaptER ONE Introduction ..........................................................................................1 Background on PILOT ...............................................................................1 Prediction Model ...................................................................................2 Prevention Model ..................................................................................2 The PILOT Experiment ..............................................................................4 Evaluation Approach ..................................................................................4 CHaptER TWO PILOT Process Evaluation .........................................................................7 Methods ................................................................................................7 Data .....................................................................................................8 Implementation of the Prediction Model ..........................................................9 Implementation of the Prevention Model ........................................................ 12 Implementation in Command 1 (Districts A and B) ......................................... 12 Implementation in Command 2 (District C) ................................................. 14 Activities in the Control Group (Districts D, E, and F) ..................................... 16 Summary ........................................................................................... 17 Results ................................................................................................ 17 Prediction Model ................................................................................. 17 Prevention Model ................................................................................. 20 Summary ........................................................................................... 23 Key Implementation Challenges .................................................................. 25 Manual Generation