Method: Health, human services, legal, and criminal justice databases were searched for empirical research on police-initiated pre-arrest diversion of adults from 2000 to the present. The authors reviewed 1,217 titles and abstracts and assessed 195 full-text articles for eligibility. Forty-seven relevant studies were included in this review. The Appraisal Tool for Cross Sectional Studies (AXIS) or the Quality Appraisal checklist for Qualitative Studies were used to assess all studies.
Results: Most of the studies (N=31) utilized quantitative methods, seven were mixed methods studies, five reported only basic updates, and four reported primarily qualitative results. Case outcomes were most commonly reported as the outcome variable, but varied greatly and included arrest, charges, diversion, time in custody, post-diversion recidivism, and time to arrest among others. Behavioral, non-criminal justice related outcomes were also measured in many studies, including drug and alcohol use, substance use treatment program referrals, program attendance or completion, mental illness symptoms, and mental health treatment engagement. Overall, police diversion programs were associated with reducing recidivism and lowering costs, though there is little association between program participation and improved behavioral health.
Conclusions and Implications: Police diversion at the point of arrest is a growing area of practice and public interest. There is an urgent need for rigorous, unbiased literature on diversion programs’ effectiveness, impact, and quality, as well as documentation of how to design, operate, and sustain successful programs. It is crucial to remember that non-significant results of diversion programs’ impact on recidivism may be seen as an endorsement of diversion, since punishment is shown to be no more of a deterrent than less costly, more humane diversion approaches. Evidence supports initiating or expanding police diversion programs to reduce recidivism, though there is little evidence that behavioral health of participants is likely to increase due to diversion without other sustained services. Cost savings to jurisdictions implementing diversion programs have been consistently high. This review study has shown police-initiated diversion programs reduce both costs and recidivism with only one study having divergent findings. Police diversion programs, alongside court diversion, sentencing reform, and decarceration can be a major social justice strategy to reduce dependence on mass incarceration to resolve social problems.