County-level Correlates of Terrorism in the United States, 1990 to 2010

This report builds on a previous one that examined the patterns and predictors of terrorism in the United States and presented descriptive data on county-level terrorism from 1970 to 2008 (LaFree and Bersani, 2012). In the current report, we were able to extend our analysis to cover the years from 1990 to 2010. As in the earlier report, we constructed a list of likely predictors of terrorism based in large part on variables that have been found to be especially important in predicting ordinary crime, including concentrated disadvantage, residential instability, and population heterogeneity. We then examined the relationship between these variables, which were drawn from the U.S. Census, and county-level terrorism attacks, taken from the Global Terrorism Database (GTD). With the expanded data analysis it soon became evident that the relationships between the county-level characteristics we examined and our measures of terrorism were in some cases different before and after the September 11, 2001 terrorist attacks. Given the impact that these attacks had on public policy regarding terrorism in the United States, this is hardly surprising. Accordingly, much of the report that follows examines these differences.