Anti Gun “Study” Filled with Flaws and Bias

Published by the Author on October 26, 2009 at 12:01 am > Pro Gun Rights Articles > Anti Gun “Study” Filled with Flaws and Bias

A study conducted by Charles Branas, who is a beneficiary of the anti gun Joyce Foundation, concluded that possessing a gun makes one 4.46 times more likely to be shot, and that guns rarely allow their owners to effectively defend themselves. I find this study’s methodology to be incredibly flawed, as it effectively lumps law abiding gun owners together with gang members who illegally carry guns and use them to commit crimes, and draws no distinction between the self defense abilities of a trained law abiding gun owner and criminals who illegally own guns and have received no training. Below are direct quotes from the study, and my comments.

The problems that the study’s own authors admit

In the discussion on page 6 of the study, the authors admit that their study has “limitations,” which are in fact fatal flaws that dwarf the rest of the study. I’ll start with a couple of those flaws:

We also did not account for the potential of reverse causation between gun possession and gun assault.

This failure to account for reverse causation is perhaps the biggest flaw in the study. Those who expect to come under violent attack, be they criminals or law abiding citizens, are much more likely to carry a gun for self defense.

For example, a drug dealer generally knows that rival drug dealers may wish to kill him in order to eliminate the competition, and that his drug addicted customers are also willing to kill him to get the drugs that he carries. The drug dealer also knows that other criminals see him as a prime target for robbery, since he will likely have both drugs and cash on his person. As a result, drug dealers tend to (illegally) carry a gun to shoot back at their rivals and would-be drug robbers. The fact that the drug dealer is selling drugs and associating with criminals explains his higher risk of being shot – not the mere presence of his (illegal) gun.

The same holds true for law abiding citizens. A jewelry store owner generally knows that criminals tend to see them as prime targets, and as a result are more likely to have a gun on them while they work than, say, a lawyer sitting at a desk in an office building. As a result, the jewelery store owner is more likely to have a gun than someone who doesn’t fear such attack. The fact that the jewelry store owner’s business is likely to be robbed by violent armed criminals explains why that jewelry store owner is more likely to be shot – not the fact that the jewelry store owner has a gun.

Certain other variables that may have confounded the association between gun possession and assault were also beyond the scope of our data collection system and, therefore, were not included in our analyses. For instance, any prior or regular training with guns was a potentially important confounding variable that we did not measure and whose inclusion could have affected our findings

Here, the study authors admit that they lump together a person who just bought an illegal gun yesterday and has received no training whatsoever with a law abiding expert gun owner who has been training for the last 20 years. It is simply unreasonable to equate the two, especially when evaluating self defense effectiveness.

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The fact is that that law abiding gun owners often manage to get their gun and use it in self defense, even when their criminal attacker(s) already have the upper hand. This homeowner managed to get his gun from a drawer, despite the fact that a criminal held a knife to him. This elderly man managed to grab a self defense gun, despite being shocked with a stun gun and beaten by a 24 year old home invader. This man managed to draw his concealed carry handgun and shoot an armed robber in self defense, despite the fact that that robber was standing behind him and pointing a shotgun at his back. This jewelry store owner managed to grab his gun from under a desk, despite the fact that two robbers were in his store, one of whom already had a gun pointed at him. This pawnshop manager managed to shoot an armed in self defense, saving himself and his teenage employee, despite the fact that a gun was being held to that employee’s throat. I could go on with many more examples, but as a properly conducted study shows, self defense works.

The problems with this study that the authors ignore

There are numerous problems with this study that the authors ignored; so many, in fact, that I don’t have the time to fully address them all. Just a couple of the more egregious problems with this study’s methodology are discussed below:

We assumed that the resident population of Philadelphia risked being shot in an assault at any location and at any time of day or night. This is an acceptable assumption because guns are mobile, potentially concealable items and the bullets they fire can pass through obstacles and travel long distances. Any member of the general population has the potential to be exposed to guns and the bullets they discharge regardless of where they are or what they are doing. As such, we reasonably chose not to exclude participants as immune from hypothetically becoming cases because they were, for instance, asleep at home during the night or at work in an office building during the day.

Here, the study authors unreasonably assumes that individuals are equally likely to be shot in any location in Philadelphia (where the study was conducted) which is simply untrue. As with just about any major city, there are some neighborhoods that are much safer than average, and some that are much more dangerous than average. A person in a high crime neighborhood is much more likely to be shot than a person in a low crime neighborhood. The fact that bullets can travel relatively long distances doesn’t change this fact, as a cursory glance at neighborhood crime statistics in any large city will show. Equating the person who lives in the crime ridden neighborhood with a person who lives in an affluent gated community is unreasonable.

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While it is true that, as a matter of physics, any person may be shot, that doesn’t mean that all people are equally likely to be shot “regardless of where they are or what they are doing.” A person who is out selling crack cocaine is much more likely to be shot than a person who is at home baking cookies. Similarly, a person who is participating in a drive-by shooting is much more likely to be shot than a person who is sitting at their desk in an office building. Equating the person who is home baking cookies with the drive-by shooting participant is simply unreasonable.

We pair-matched case participants to control participants on the date and time (within 30- minute intervals; i.e., 10:30 pm, 11:00 pm) of each shooting. This was done because the factors we planned to analyze, including gun possession, were often short-lived making the time of the shooting most etiologically relevant. . . We did not pair-match case participants and control participants on location.

Once again, the methodology used in this study is flawed. Comparing an (illegally) armed criminal who is dealing drugs at 11:00 PM to a law abiding person who is is asleep at home and not holding a gun at the moment does not tell us much, other than the already known fact that dealing illegal drugs is a dangerous activity.

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This study’s methodology was deeply flawed, and the conclusions it reaches are therefore invalid. Equating criminals with law abiding citizens leads to inaccurate results when evaluating whether gun ownership leads to increased risk of being shot. Similarly, lumping together well trained gun owners with inexperienced individuals who illegally owns guns does not produce a valid result when evaluating the effectiveness of armed self defense.

Those interested in more information about armed self defense are encouraged to read the two studies shown on this page, which demonstrated that gun ownership for self defense is effective, as well as the many real life examples of armed self defense.

My thanks to everyone who has emailed me about this study.

Unarmed Self Defense and Disaster Preparedness e-books:

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  • Jewish Marksman

    The researchers are complete morons. Your jewelry store example hits the nail on the head. They may as well have included our soldiers in Iraq as well. I've already seen the anti-gun blogs distorting this study for their own ends.

    Be warned: the NIH and OSHA are starting to look into gun related injuries. NIH, probably coupled with Obamacare, want to study the "costs" of gun violence on the medical system…for what purpose, I wonder? OSHA to ban guns in the workplace, of course.

    These junk studies are used by anti-gun politicians and bureaucrats to justify their dangerous policies.

  • James

    Nice analysis! Unfortunately, many anti-gun organizations will use this study to further their pockets and political fame.

  • Edward R. Hermann, CE, PhDevidence to evidence to support claims

    Rebuttal starts with conclusions, seeks only anecdotal evidence to support adopted positions and resorts extensively to name calling biased comments. No observance of scientific methods.

    • The Author


      I respectfully disagree. In this article, I pointed out the flaws in that “study,” the bias of the researcher, etc.

      You comment, on the other hand, consists of nothing more than conclusions unsupported by any facts or reasoning.

    • kgbduck

      Even the NCIB has issues with the methodology used
      If bullets behaved like malaria mosquitos, just buzzing around at all hours of the day, then this study might make sense.
      But they are not; this “study” is akin to noting that people wearing parachutes are more likely to be injured falling from airplanes than people not wearing parachutes.

  • kgbduck

    I read the data and it appears that while 5.92% of the people shot were armed, 7.16% of the “control” group of random non-shot Philadelphians were armed. On it’s face it would look like the shot folks were less likely to be armed than the “control” group. The study only shows a higher chance for armed people to be shot “after we adjusted for confounding factors”. And of course it does not say what those confounding factors are.