摘要：A widely publicized but unpublished study of the relationship between gun shows and gun violence is being cited in debates about the regulation of gun shows and gun commerce. We believe the study is fatally flawed. A working paper entitled “The Effect of Gun Shows on Gun-Related Deaths: Evidence from California and Texas” outlined this study, which found no association between gun shows and gun-related deaths. We believe the study reflects a limited understanding of gun shows and gun markets and is not statistically powered to detect even an implausibly large effect of gun shows on gun violence. In addition, the research contains serious ascertainment and classification errors, produces results that are sensitive to minor specification changes in key variables and in some cases have no face validity, and is contradicted by 1 of its own authors’ prior research. The study should not be used as evidence in formulating gun policy. IN EARLY OCTOBER 2008, THE National Bureau of Economic Research posted on its Web site a working paper by Duggan et al. titled “The Effect of Gun Shows on Gun-Related Deaths: Evidence from California and Texas.” 1 A University of Michigan press release announced the study with the headline “Gun shows do not increase homicides or suicides” and began as follows: A new study finds no evidence that gun shows lead to substantial increases in either gun-related homicides or suicides. The…study also shows that tighter regulation of gun shows does not appear to reduce the number of firearms-related deaths. 2 Not surprisingly, the paper received nationwide publicity. Just 6 weeks after its release, it was the topic of a relentlessly favorable cover article in America's 1St Freedom , the monthly official journal of the National Rifle Association. 3 To our knowledge, the working paper has not been published in a peer-reviewed publication. Anecdotal reports from policy advocates and policymakers suggest that it has nonetheless become influential in the continuing debate about how best to regulate gun shows and gun commerce to prevent violence. We believe that the study discussed in the working paper contains serious errors in design and execution that fatally compromise its findings. Correspondence with the authors 4 , 5 did not lessen our concerns and, because the paper remains in circulation, we seek to share those concerns with the research and policy communities. For brevity's sake we confine our comments largely to the study's findings for homicide, although we have similar concerns about the study's findings for suicide.
