September 25, 2007
City Homicide Rankings Adjusted for Differences in Crime-Producing Factors
Researchers with the Improving Crime Data (ICD) Project today released rankings of 65 large US cities based on rates of homicide (number of homicides divided by the city's population) in 2006. 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).
The FBI discourages ranking cities by their crime rates because cities differ in poverty, unemployment, 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 by differences across the cities in the level of socioeconomic disadvantage (a measure combining poverty, unemployment, race composition, and female-headed families). 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 socioeconomic differences are statistically controlled. Atlanta falls from number 11 in the unadjusted homicide ranking to number 51 after statistical adjustment. Milwaukee drops from number 15 to number 62. By contrast, San Jose, CA, rises from number 62 to number 24 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 socioeconomic disadvantage. An increase in rank means that a city has a higher homicide rate than would be expected based on its level of disadvantage. Cities with roughly the same ranking after the statistical adjustment have homicide rates that would be expected given their level of disadvantage. Such cities include Baltimore, which ranks second in both the unadjusted and adjusted rankings, and El Paso, TX, which is at the bottom of both rankings.
The 65 cities in the study contain about 17% of the nationís population but accounted for 40% of the homicides committed in the U.S. in 2006.
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.
Professor and Chair Department of Criminology and Criminal Justice University of Missouri-St. Louis (314) 516-6717 email@example.com Alfred Blumstein J. Erik Jonsson University Professor of Urban Systems and Operations Research Carnegie Mellon University (412) 268-8269 firstname.lastname@example.org Robert Friedmann Professor Department of Criminal Justice Georgia State University (404) 413-1020