Comments on “Investigating the Link Between Gun Possession and Gun Assault”

College of Criminology and Criminal Justice, Florida State 
University, Tallahassee, FL 32306-1127 (850) 894-1628

Comments on forthcoming article by Branas et al., AJPH 2009

The article by Branas and his colleagues (forthcoming in the American Journal of Public Health)  is the very epitome of junk science in the guns-and-violence field – poor quality research designed to arrive at an ideologically predetermined conclusion.  Like all articles in on this topic published in the AJPH, it concludes that guns (no matter who possesses or uses them) invariably raise the risks of violence.  This is not what competent research indicates, but it is certainly what the peculiar body of poor quality research appearing in medical and public health journals almost always concludes.

The authors conclude that “on average, guns did not protect those who possessed them from being shot in an assault” and that successful defensive gun uses are unlikely.  In fact, none of the evidence presented by the authors actually has any relevance to the issue of the effectiveness of defensive gun use, for the simple reason that at no point do they ever compare crime victims who used guns defensively with victims who did not.  Instead, they made only the essentially irrelevant comparison between people who were shot in assaults with the rest of the population, noting whether gun possession was more common among the former than among the latter.  Not surprisingly, after controlling for a handful of (badly chosen) control variables, they found that gun possession is more common among gunshot victims.

This pattern, however, says nothing about the effectiveness of defensive gun use, but rather is merely a reflection of the fact that the same factors that place people at greater risk of becoming assault victims also motivate many people to acquire, and in some cases carry away from home, guns for self-protection.  In sum, this is what researchers refer to as a “spurious” association – a non-causal statistical pattern due to the influence of some third factor(s) on the purported cause (gun possession) and the effect (gunshot victimization).  For example, being a drug dealer or member of a street gang puts one at much higher risk of being shot, but also makes it far more likely one will acquire a gun for protection.

Previous published research, however, has directly compared crime victims who used guns with victims who used other self-protective strategies (including doing nothing to resist), and reached precisely the opposite conclusions from those at which Branas et al. arrived (Kleck 1988; Kleck and DeLone 1993; Southwick 2000; Tark and Kleck 2004).  Significantly, Branas et al. ignore all but one of these studies, and do not share with readers the main finding of the one study they do mention in passing (Kleck and DeLone 1993) – victims who resisted with guns were less likely to be injured that those who did not.  Indeed, all published research to make such direct comparisons has yielded the same conclusion.

The most authoritative study (Tark and Kleck 2004) used data from large-scale surveys conducted by the federal government (the National Crime Victimization Survey), covering large samples that were representative of the entire U.S. population, compared 18 different self-protection victim strategies, and controlled for far more confounding variables than Branas et al. did.   The results indicated that the probability of success in defensive uses of guns approaches 100% – it is virtually unheard of for a crime victim to be injured after using a gun for self-protection.  More specifically, only 2% of gun-wielding victims were injured after using a gun for self-protection (p. 878).  On the rare occasions that gun-using victims were hurt, it was almost always injury that came first, followed by armed resistance – i.e., injury provoked previously reluctant victims into finally using their guns.

Strictly speaking, the results of Banas and his colleagues do not conflict with those of prior researchers; rather, they are simply irrelevant, and do not actually bear on the use of how effective defensive gun use is.  The authors draw a non sequitur conclusion from irrelevant evidence.  They find that gun shot victimization is more common among those who have guns, and conclude that gun possession raises one’s risks of being shot.   It is precisely as if medical researchers found that insulin use is more common among persons who suffer from diabetes than among those who are not diabetic (something that is most assuredly true), and concluded that insulin use raises one’s risk of diabetes.  This silly conclusions would certainly come as a surprise to medical researchers, and is obviously wrong.  So is the conclusion drawn by Branas et al.

Cited Studies
Kleck, Gary
  1988 “Crime control through the private use of armed force.”  Social Problems 35:1-21. 

Kleck, Gary and Miriam A. Delone
1993 “Victim resistance and offender weapon effects in robbery.”  Journal of Quantitative Criminology. 9:55-81.

Southwick, Lawrence
  2000   “Self-defense with guns.”  Journal of Criminal Justice 28: 351-370. 

Tark, Jongyeon, and Gary Kleck. 2004.  “Resisting Crime.”  Criminology 42:861-909.