This paper describes a randomized controlled trial, aimed at testing the effectiveness of 15-minute high-visibility police patrols to high crime and call for service hot spots; she lays out her research methodology, outcomes, and policy implications.
This study introduces the California Crime Harm Index (CA-CHI) and explores in what context a Crime Harm Index is a meaningful measure, comparing crime count outcomes to the CA-CHI. The author decouples violent and property crime to determine when harm is a better indicator of reduction rather than counts. The author describes the Sacramento Hot Spot Experiment (SHSE), which was a 90-day randomized controlled trial testing the effectiveness of 15-minute high-visibility police patrols to high crime and call for service hot spots. In this paper, the author translates Part I crimes counts into the CA-CHI. She conducted t-tests for both Part I crime and CA-CHI between experimental and control hot spots. The author calculated effect sizes to observe the differences between Part I crime and CA-CHI. Part I crimes were decoupled into violent and property crime and similarly analyzed. The SHSE’s effect size using the decoupled violent and property crime CA-CHI as the outcome measures was less than when the Part I crime counts were analyzed. Violent crime had too small a sample size to properly analyze. Results indicated that the impact of the SHSE is not as strong when using the CA-CHI to evaluate crime outcomes compared to crime counts. The reduction in harm is driven largely by the property crime reductions. The sensitivity of the CA-CHI is reduced when violent crime is excluded. The author suggests that CA-CHI or any derivation of a CHI may not be a useful tool when using a harm index on a small study, dataset, or municipality. Publisher Abstract Provided