How to Lie with Rape Statistics …
More: ccbf136055970d58-A5_Yung.pdf
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.