Philip J. Cook: Testing Instrumentality: Caliber as a Determinant of the Likelihood of Death in Firearms Assaults

Wednesday, January 17, 2018 - 12:00pm to 1:30pm

309 McNeil Building, 3718 Locust Walk


 Question: Is the likelihood of death for firearms shooting victims influenced by the caliber of the firearm?

Findings:  An analysis of 5 years of data extracted from investigation files kept by the Boston Police Department determined that the case-fatality rates of firearms assaults with gunshot injury increased significantly with the caliber of the firearm.  Caliber was not significantly correlated with the number or location of wounds.  The predicted (ex ante) probability of death for gun assaults was only slightly higher for those who in fact died, than for those who survived.

Meaning: The findings are foundational to the debate over whether deadly weapons should be better regulated.  The contrary view, that whether the victim lives or dies is determined largely by the assailant’s intent and not the type of weapon, continues to have sway, and is used by pro-gun advocates as the basis for claiming that regulating guns is futile.   Our findings suggest that in fact chance (rather than intent) plays the predominant role in whether the victim lives or dies in criminal-assault shootings , and that many lives would be saved if assailants only used small caliber handguns.   This finding supports Zimring’s (1972) conclusions from his seminal study.  A reasonable extrapolation is to predicting the effect of replacing all types of guns with knives.


Philip J. Cook is ITT/Sanford Professor of Public Policy and Professor of Economics and Sociology at Duke University. He served as director and chair of Duke’s Sanford Institute of Public Policy from 1985-89, and again from 1997-99. Cook is a member of Phi Beta Kappa, and an honorary Fellow in the American Society of Criminology. In 2001 he was elected to membership in the Institute of Medicine of the National Academy of Sciences.

Cook's primary focus at the moment is the economics of crime. He is co-director of the NBER Work Group on the Economics of Crime, and co-editor of a NBER volume on crime prevention. Much of his recent research has dealt with the private role in crime prevention. He also has several projects under way in the area of truancy prevention.