Improving Crime Data

Researchers with the Improving Crime Data (ICD) Project today released rankings of 65 US cities based on rates of homicide (number of homicides divided by the city's population) in 2005. The rankings reflect 1) the raw rates per 100,000 population and 2) the rates adjusted for differences across the cities in demographic and social factors. The adjusted rates result in important changes in the ranking for several cities (see Table 1).

Police and other public officials, especially in high-crime cities, often complain that ranking cities by their crime rates -- as in the recent Morgan Quitno Press crime rankings -- is misleading and unfair because cities differ in poverty, racial disadvantage, and other crime-producing factors beyond their control. Criminologists Richard Rosenfeld, Alfred Blumstein, and Robert Friedmann applied a statistical model that adjusts each city's homicide figures for such factors. The researchers maintain that the model produces a more meaningful comparison of city homicide levels, especially for providing insight into the effectiveness of criminal justice policies and programs.

Several cities fall or rise substantially in rank when differences in economic disadvantage, stability, divorce rates, and population size are statistically controlled. Atlanta falls from number 11 in the unadjusted homicide ranking to number 52 after statistical adjustment. Cleveland drops from number 9 to number 50 and Detroit from number 2 to 45. By contrast, San Francisco rises from number 26 to number 1 (3 years in a row) after statistical adjustment. Table 1 presents the rankings for all 65 cities.

A drop in rank indicates that a city has a lower homicide rate than would be expected based on its level of economic disadvantage, stability, divorce rate, and population size. An increase in rank means that a city has a higher homicide rate than would be expected based on these factors. Cities with roughly the same ranking after the statistical adjustment have homicide rates that would be expected given the crime-producing factors. Such cities include Baltimore and Washington, DC, which are near the top of both the unadjusted and adjusted rankings, and El Paso, TX, Corpus Christi, TX, and Honolulu (HI) which are at the bottom of both rankings.

The 65 cities in the study comprise all but two cities with populations greater than 250,000 in 2000. (Homicide data were not available for Wichita and New Orleans.) They contain about 17% of the nation’s population but accounted for 39% of the homicides committed in the U.S. in 2005.

The homicide study was conducted for the project "Improving Crime Data" (ICD). ICD is funded by the National Institute of Justice. Technical details on how the city homicide rates were adjusted can be found on the ICD website (Improving Crime Data).

Robert Friedmann, Ph.D., of Georgia State University and Richard Rosenfeld, Ph.D., of the University of Missouri-St. Louis are principal and co-principal investigator on the project. The crime monitoring program is sponsored jointly by ICD and the National Consortium on Violence Research (NCOVR). Alfred Blumstein, Ph.D., is the director of NCOVR which is supported by the National Science Foundation, and headquartered at Carnegie Mellon University.

Improving Crime Data

City Homicide Rankings Adjusted for Differences in Crime-Producing Factors