RACE ON POLICING: Data Sources and Estimation Approach
The data set used in this paper is a panel of data containing the 134 U.S. cities with population greater than 100,000 as of the year 1975. Panel data, with city-fixed effects and time dummies included as controls, are less likely to be adversely affected by unobserved heterogeneity than would cross-sectional data from cities in a given year. The limiting factor on our sample is data on the racial composition of municipal police forces, taken from the EEO-4 survey of governments conducted annually by EEOC since 1973. Working in concert with the technical staff of EEOC, we have obtained access to data for the years 1977, 1981, 1984, 1986, 1989, and 1993. For each department of the local government, the racial and gender composition of the work staff is reported by functional category (e.g. protective services, officials and administrators, administrative support, professionals).
Although greater detail on race is available in the data, we limit our analysis in this paper to the broad classifications of white and non-white. The primary motivation for doing so is concern over lack of comparability of the definition of Hispanic across data sources. In some specifications, cities with Hispanic populations greater than ten percent using the Census definition are eliminated as a check on the sensitivity of the results read more.
We focus our analysis on those members of police departments whose job function is protective service. This definition captures patrol officers, excluding both officers assigned to desk duties as well as supervisors. This categorization is closely related to, but somewhat more restrictive than, the Federal Bureau of Investigation’s (FBI) measure of sworn police officers.
For the cities in our sample, the raw correlation between sworn police officers, as reported in the FBI’s Uniform Crime Reports, and the EEOC measure is .92. The EEOC-reported value is on average 18 percent smaller than the FBI measure. Summary statistics for the EEOC measure of sworn police officers by race, along with all of the other variables used in the analysis, are presented in Table 1.
The only crime variable for which a long panel of racial breakdowns by city is available is arrests. These data are collected by the FBI and are available disaggregated by crime category on an annual basis. Including a relevant set of control variables, the impact of white and nonwhite officers on white and non-white arrests can consequently be directly estimated.
Unfortunately, equivalent data on crime commission by race are not available annually at the city level. As a consequence, we are forced to make due with aggregate city-level data, indirectly obtaining estimates of the coefficients of interest through the modeling assumptions imposed in the preceding section. The measure of crime used in estimating equations 10 and 11 is per capita crime as proxied by reported crime statistics compiled annually by the FBI in Uniform Crime Statistics. The police variables are once-lagged to minimize the endogeneity.