Yes, it’s more junk science out of the UPenn School of Medicine. We’ve become accustomed to seeing some horrendously bad junk science out of the medical academic sector where firearms are concerned, but this is worse than most. I honestly think this one is, methodologically speaking, possibly even worse than the Kellermann study.
News release here, American Journal of Public Health abstract here.
Let’s briefly summarize the methodology here.
First, Dr. Branas compiled a list of 677 people shot in the course of assaults in Philadelphia between 2003 and 2006, and determined that 6% of them were reported to have been in possession of a gun in a holster, pocket, waistband or vehicle when they were shot. (Note: By elementary arithmetic, that means 94% of those shot were unarmed.)
Next, Dr. Branas and his intrepid law students picked up the phone book, randomly called 684 people in Philadelphia who had not been assaulted, soon after reported shootings, and asked them whether at the time of the shooting they had a gun in their possession.
From these two sets of data, Dr. Branas somehow derived the conclusion that possessing a gun makes you 4.5 times more likely to be shot in an assault.
... No, I don’t see a logical path from data to conclusion either. But I have a pretty good idea the conclusion was predecided and the study designed to fit it.
So! Just for fun, let’s play a game. Let’s see if we can think of ALL of the logical and methodological problems with this study.
Have at it!
