The present study employs a quasi-experimental design to evaluate the effects of a mandatory sexual assault kit (SAK) testing policy on rape arrests in a large western US jurisdiction. We use a Bayesian structural time-series model and monthly data on arrests for rape from 2010 through 2019. In the post-implementation period, we observed a downward trend in the arrest rate for rape. Based on the results, the most conservative interpretation of our findings is that the policy implementation did not affect rape arrest rates. While mandatory SAK testing policies are often advocated for based on the belief that they will increase arrest rates for sexual assault (among other proposed benefits), we add to growing empirical evidence that policy interventions beyond mandatory SAK testing are needed to increase arrest rates for sexual assault. Jurisdictions that currently use mandatory SAK testing policies are encouraged to assess stakeholders' experiences to proactively address resource allocation, consider other policies that may increase accountability for sexual assault offenders, and utilize victim service providers to support other measures of success with victims in instances where no arrest is made.
Researchers examined whether requiring police to test all sexual assault evidence kits would lead to more arrests for rape, but found that arrest rates actually declined or stayed the same after the policy was implemented in one large city. This challenges the common assumption that mandatory testing of rape kits automatically translates into more offenders being caught and arrested. The findings suggest that police departments need additional reforms beyond just testing requirements to effectively investigate sexual assault cases and hold perpetrators accountable.
(AI-generated summary, v1, January 2026)
Citations: 15 (as of January 2026)