The Defensive Gun Use Lie and the Gun Lobby’s Firehose of Falsehood - Part 4
The Defensive Gun Use Lie and the Gun Lobby’s Firehose of Falsehood - Part 4
Comparing defensive gun use and cocaine
By: Devin Hughes
This is Part 4 of a 12-part series debunking the defensive gun use myth. Part 1 examined recent high-profile incidents of DGUs gone wrong, how the NRA has seized on the defensive gun use narrative to further its guns everywhere agenda, and what constitutes a DGU. Part 2 looked at the academic origins of the DGU myth and its massive flaws. Part 3 delved into why surveys of statistically rare events produce substantial overestimates. Today we will explore the surprising parallel pro-gun academic Gary Kleck draws between defensive gun use and using cocaine, and its ramifications for the DGU debate.
Part 4: Comparing defensive gun use and cocaine
When confronted with the multidisciplinary evidence that surveys of statistically rare events produce substantial overestimates, Dr. Gary Kleck rejects these claims and argues that the proper comparison to draw with defensive gun use are surveys of criminal behavior. As we will see though, not only do Kleck’s arguments commit the base rate fallacy, his own formulas prove the mathematical impossibility of his own results.
Kleck correctly points out that surveys relying on self-reporting of criminal behavior consistently underestimate that behavior as people don’t want to implicate themselves. Kleck argues that this framework applies to his own survey as anywhere from 36-64% of the respondents were either illegally using or carrying the firearm during their DGU. More specifically, Kleck compares surveys of defensive gun use to surveys of illicit drug use among patients at a walk-in clinic and juvenile arrestees using cocaine.
In a 2018 paper, Kleck doubles down on this defense, pointing out that in “one of the largest scale tests of drug reporting validity ever conducted” with nearly 22,000 arrestees, “For every drug, false positives were rare, and greatly outnumbered by false negatives. False negatives outnumbered false positives by a factor of 15.4 for cocaine, 3.1 for opiates, 3.3 for amphetamines, and 1.3 for marijuana.”
However, comparing raw numbers of false positives and false negatives in this fashion commits the base rate fallacy by ignoring the underlying numbers of true positives and negatives. What is important is the relative rate of false positives and negatives.
In the surveys Kleck cites, illegal drug use among arrestees is not a rare event, with a majority of participants having some form of illegal substance in their system. This means there will be plenty of true positives (respondents having done drugs) in the survey, which means there are a lot of opportunities for the people who have done drugs to lie about it (a false negative), creating the false negative to positive discrepancy Kleck describes.
Yet even the most aggressive estimates of defensive gun use still have it as a statistically rare event.
In Kleck’s cited drug surveys, more than 60% of the arrestees actually did drugs. This is compared with 2% or less of the survey population in Kleck’s defensive gun use surveys reporting a DGU. The difference between 60% and 2% is massive when it comes to the relative rate of false positives and false negatives.
In fact, assuming for the moment that defensive gun use is as socially undesirable as cocaine use, Kleck’s own calculations disprove his claim. Because defensive gun use is a statistically rare event, the rate of false negatives would need to at least be 100 times larger than false positive rate to avoid overestimating DGUs. Kleck’s own math in a different paper puts the number at 135 times larger.
In other words, using a gun in self-defense would need to be at least eight times more socially undesirable than cocaine usage for Kleck’s defense of his survey to be valid using his own numbers.
It is worth pausing here to reflect on the fact that Kleck’s primary defense of his survey results is comparing the social desirability of defensive gun use to cocaine usage.
This is despite the fact that of the DGUs in Kleck’s survey, 46.1% of the respondents indicate that their action at least “might have” saved someone’s life, with 15.7% saying it “almost certainly would have” saved someone’s life. It is not hard to imagine that at least some survey respondents would think saving someone’s life would appear heroic and socially desirable, thereby leading to potential false positives. Further, in his initial research Kleck states, "We made no effort to assess either the lawfulness or morality of the respondents' defensive actions."
The debate over the social desirability of defensive gun use represents one of the foundational hypocrisies of the gun debate.
In writings meant for public consumption, as well as testimony in court cases, Kleck touts the benefits of defensive gun use for society and bemoans the impact stricter gun laws might have on the ability of people to use guns defensively. The gun lobby and its allies tout the 2.5 million DGU number in every possible venue, and cheer cases of defensive gun use as critical to public safety.
Yet in academic papers, the pro-gun tune changes. Instead, defensive gun use is treated as a socially undesirable scourge that is as shameful as using cocaine regularly.
If Kleck’s academic defense was realistic, we would see a different public debate in which the gun lobby and its allies vehemently denied millions of DGUs given the illegality and undesirability of that behavior. But his defense isn’t realistic, and even if he was correct about the social undesirability of DGUs, it still would not be sufficient to save his surveys’ results.
However, while Kleck’s defense of his surveys remains fatally flawed and he is extremely off the mark when it comes to social desirability, he is correct to be concerned about illegality of the defensive gun uses being reported.
Stay tuned for Part 5 of our 12-part series on defensive gun use, which will highlight that most reported cases of DGUs in surveys are actually aggressive illegal actions.
Devin Hughes is the President and Founder of GVPedia, a non-profit that provides access to gun violence prevention research, and data.
Image of cocaine by Jiri Plistil from Pixabay; illustration by Chen from Pixabay