99 Iowa L. Rev. 1197 (2014)

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Abstract

During the last two decades, many police departments substantially undercounted reported rapes creating “paper” reductions in crime. Media investigations in Baltimore, New Orleans, Philadelphia, and St. Louis found that police eliminated rape complaints from official counts because of cultural hostility to rape complaints and to create the illusion of success in fighting violent crime. The undercounting cities used three difficult-to-detect methods to remove rape complaints from official records: designating a complaint as “unfounded” with little or no investigation; classifying an incident as a lesser offense; and, failing to create a written report that a victim made a rape complaint.

This study addresses how widespread the practice of undercounting rape is in police departments across the country. Because identifying fraudulent and incorrect data is essentially the task of distinguishing highly unusual data patterns, I apply a statistical outlier detection technique to determine which jurisdictions have substantial anomalies in their data. Using this novel method to determine if other municipalities likely failed to report the true number of rape complaints made, I find significant undercounting of rape incidents by police departments across the country. The results indicate that approximately 22% of the 210 studied police departments responsible for populations of at least 100,000 persons have substantial statistical irregularities in their rape data indicating considerable undercounting from 1995 to 2012. Notably, the number of undercounting jurisdictions has increased by over 61% during the eighteen years studied.