The effect of changing the military’s sexual assault laws on law enforcement investigative findings in the U.S. Army

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Objective: In 2007, Congress changed the military’s sexual assault laws as part of an effort to improve sexual assault case processing. This study looked at the U.S. Army law enforcement investigative finding for every sexual assault reported to the Army from 2004 through June 2012, along with every nonsexual assault. Our objective was to measure whether the legal intervention affected the investigative findings made by Army law enforcement officers in sexual assault cases (penetrative, nonpenetrative, and combined) as compared to assault cases (aggravated, simple, and combined). Hypotheses: We hypothesized that we would not find evidence that the legal intervention affected the rate of sexual assault cases labeled as “founded” by Army law enforcement, such that for the best-fitting time-series models, any difference in the residuals of the means before and after the intervention would not be statistically significant. Method: We received data from the U.S. Army on all sexual assaults and nonsexual assaults from 2004 through June 2012. The data comprised 47,058 observations. We used time-series analysis with autoregressive integrated moving average modeling. The variable tracked over time was the ratio of the proportion of founded sexual assault cases to the proportion of founded nonsexual assault cases. We then conducted t tests of the means of the residuals before and after the legal intervention. Results: The difference in the means of the residuals before and after the intervention was not statistically significant for combined sexual assaults versus combined assaults, penetrative sexual assaults versus aggravated assaults, or nonpenetrative sexual assaults versus simple assaults. Conclusions: This reform to sexual assault laws does not appear to have affected sexual assault case processing by U.S. Army law enforcement.