Utility of indices of gun availability in the community.

OBJECTIVE To estimate the degree to which the proportion of homicides and suicides committed with a gun is associated with reported availability of firearms across Chicago neighbourhoods. METHODS Data were collected as part of the Project on Human Development in Chicago Neighborhoods (PHDCN), a combined neighbourhood and individual level study of the city of Chicago. The study used data from 837 PHDCN participants between the ages of 17 and 22, residing in 170 different neighbourhoods. Gun availability was measured via participant reports on whether they had carried a gun and whether they perceived gun access to be easy in their community. Data on suicides and homicides were obtained from the Chicago Department of Health. RESULTS A 10% change in the proportion of homicides committed by a gun in a neighbourhood was associated with a 20% increase in both the odds of reported gun access and reported gun carrying (p=0.002 and 0.048, respectively). The proportion of firearm related suicides was not associated with either of those self reported measures. CONCLUSIONS The proportion of firearm related homicides, but not the proportion of firearm related suicides, is a useful predictor of gun availability across small areas such as neighbourhoods.