Previous Post
Next Post

Our man Leghorn did an excellent job fisking the gun control movement’s claim that “tight” gun control laws led to a reduction in firearms-related homicides. The National Shooting Sports Foundation’s Legislative and Policy Research Director Elizabeth Karasmeighan had a bash at Bloomberg’s anti-ballistic bile, too ant it’s worth a second look . . .

A recent study  published in the American Journal of Public Health makes the spurious claim that Connecticut’s 10-year old handgun permit-to-purchase law kept the state’s firearms homicide rates (FHRs) lower than it otherwise would have been. To get to this unfounded conclusion, the authors, all from the anti-gun Bloomberg School of Public Health at Johns Hopkins University, created a set of assumptions that perfectly match their desired conclusion, cherry-picked years and fished for convenient variables.

While it is well documented that homicides with firearms have fortunately been on a steady decline nationwide over the past decade, the authors use a weak research design to compare Connecticut’s actual post-1995 FHRs with what they claim is an estimate of what those rates would have been in a hypothetical situation of the state not passing the handgun law.Without even looking at the study design, it is wildly implausible to argue that one fairly modest change in law was solely responsible for a 40 percent decrease in FHRs. The law included changes like requiring prospective handgun buyers to appear in person to apply for a permit and requiring completion of a handgun safety course. These are not laws that criminals follow.

While flawed, the study’s design is simple. Use FHRs in other “control states,” as well as control variables thought to affect homicide rates to predict what Connecticut’s rates would have looked like if the law were not enacted. Then the authors compare Connecticut’s actual rate with the rate predicted by their model for their “synthetic Connecticut” and attribute any difference to the “effect” of the handgun permit law.

The key issue is whether the law caused the rate drops, or whether some combination of a host of other causal factors was instead responsible.  The authors acknowledge that their research strategy depends on an assumption that no other factors could have contributed to the drop, but fail to mention how extremely implausible this assumption is.  It’s safe to say there were certainly other homicide-affecting factors changing in the post-law period beside the gun law revisions.

The most conspicuous way that the authors distorted their findings was by arbitrarily excluding data points for 2006-2013, which tend to contradict their claim that the law reduced FHRs. As our chart here shows, the authors extended their time series just far enough to include the unusually low rate post-law years of 2002-2005, but excluded the eight post-law years of 2006-2013 in which the rates were on average 41% higher than in the 2002-2005 period.

CT Firearm Homicide Rates

And this is just the tip of the iceberg when it comes to questions raised by this study. Considering the new law raised the legal age for handgun purchases from 18 to 21, why did the authors not use police arrest data to analyze the rate among 18-20 year olds, where the effect should have been especially strong?

Also, why did the authors not test their findings by using a different, well-established way of estimating what FHRs would have been absent the law by simply using Connecticut’s own pre-1995 trends to forecast post-1995 rates? Perhaps because this would have indicated that CT was going to experience substantial rate drops after 1995 regardless of whether they revised their gun laws?

And how could the authors ignore the trend visible in their study that shows the rate decline had already begun two years before the law was enacted in October 1995 and actually continues declining at roughly the same rate as before the law? Unlike Connecticut’s tax increases, the effect of gun control laws cannot be retroactive.

When choosing states with which to compare Connecticut, the authors excluded from consideration any states that already had a permit-to-purchase law in 1995, guaranteeing that the states most similar to Connecticut were systematically disqualified from consideration as controls.  As a result of this arbitrary decision, the authors included as controls states places as socially and culturally different from Connecticut as Nevada, and California, while excluding far more similar nearby states like Massachusetts, New York, and New Jersey.

And as noted in a Reason Foundation blog pointing out even more problems with the study, one local state that was used as a control, Rhode Island, appears to be an outlier in the sense that FHRs rose during this period.Even with this in mind, the study shows that the all of the control states also followed the trend for real Connecticut, suggesting a broader national trend not driven by state law.

Even the control variables chosen are conspicuously flawed. They include as controls variables found in most prior research to have no effect on crime rates (such as the number of law enforcement officers, official unemployment rates), while excluding variables consistently found in prior research to affect homicide rates, such as the divorce rate.

Finally, the authors seem to base all of their conclusions on the fact that firearm homicides declined after 1995 but non-firearm homicides did not.  What they fail to note is that prior research shows firearm homicide rates are far more volatile than non-firearm rates – both increases and decreases in firearm homicides are proportionally larger than increases or decreases in non-firearm homicide rates, regardless of whether there were any changes in gun control law that could have caused the changes in homicide rates.

The data clearly show that Connecticut’s FHRs declined after 1995, and the reduction may even have been proportionally larger than reductions in other states, but nothing in the authors’ methods allows them to determine whether the new law was responsible for any of the reduction. This study is nothing but another weak Bloomberg-funded argument for more gun control.

Previous Post
Next Post


  1. Think a far more interested article would be if anyone could discern WHY anti-freedom people lie, is it ” the ends justifies the means? Seriously can this be investigated, enough former anti-gun people are in prison, ask them.

    • These guys lie for several reasons: (1) they are gun hating liberals; (2) Bloomie gave them a boatload of money to say what he wanted them to say. He who pays the piper calls the tune; and (3) these are not peer reviewed studies appearing in academic journals, thus avoiding the immediate and well-deserved criticism and approbation of their peers..

      My (deceased) father-in-law was a former dean of the Johns Hopkins School of Public Health (i.e., pre-Bloomberg). And although he was a dyed-in-the wool hard core liberal (and probably anti-gun after having been at Dachau during his service in WWII), I cannot believe but that he would have been utterly appalled and embarrassed by the lack of academic vigor reflected in these “studies.”

      • Actually, Mark, the study in question did appear in a peer-reviewed journal. I suspect the peers who conducted the review were “experts” in the so-called public health crisis of gun violence (aka fellow antis) rather than experts in any kind of research, science or statistical analysis.

        In fact, the study almost certainly violates the American Journal of Public Health’s ethics policy (read the part about “scientific misconduct” here: along with just about any standards for credible research.

        What they did is basically akin to saying the Supreme Court has been silent on the right to keep and bear arms and basing that assertion on the fact that there was a blank half-page somewhere in the middle of the Heller decision.

  2. If what Bloomberg and the other obsessed anti gunners were peddling was So *Good*, why do they have to lie about it? Really all y’all? If it was all that and truthful, wouldn’t we be beating a path to y’all’s door over it?

    • Absolutely. Every time one of these yoyos comes up with this crap, we all have to stand up, throw our shoes, and yell LIAR!

  3. There’s the old saying that you can fool some of the people all the time, and all the people some of the time, but you can’t fool all the people all of the time. That saying is actually very true. Bloombag knows this. Still, he skirts that fact by utilizing tricks that are really nothing much more than slight of hand tricks. He and his minions manipulate numbers, spread a little money around here and there, have some media folks in his pocket and the then the truth doesn’t matter. There’s one little problem with that plan, the truth DOES matter. Lies have to be covered, the truth can run around naked.
    Bloombags lies are destined to fail. The truth has no price. The people in this part of the world love our freedom and history is on our side and NOTHING on this blue green planet will ever change that, no matter how much money Bloombag spends. A spoon full of dirt is still a spoon full of dirt and no amount of money will make it a spoon full of sugar. You can spray paint it white, you can put a bag of sugar next to it, you can say it’s sugar, but it’s still dirt.

  4. If I was designing this study I would also compare demographics and income levels of any state considered a “control state” and of course how many Obama voters are in State A versus CT as that would certainly skew the results.

  5. isn’t that considered academic fraud that should be reported to the school and used as the basis for disciplinary action up and including termination?

    • Normally yes. However, it was for a “good cause” and to them, the ends always justify the means. As such, being the cynic I am, the researcher will probably be given a promotion and a bonus. I guarantee though, had it been a pro-gun study, the researcher would have been tarred, feathered and run out on a rail before the ink had dried.

    • If that were true, there would be almost no climate “scientists” employed by those universities anymore, either. Both groups remain employed – and publicly funded – for the same reason: they further a political agenda that has nothing to do with science.

      Seriously, these Bloomberg flacks “hide the decline” as well as Michael Mann, et al.

    • Academic Fraud both has a very high standard and is very hard to prove. Equating bad data or methodology with intent takes a lot, especially when that paper has gone through peer review. Frequently you find yourself going up against institutional bias and that is where on finds the real stonewall. The appropriate way to challenge this would be though a contrasting study. The odds of such making it through peer review? While it’s not actually zero, I sure wouldn’t recommend holding your breath. Ask anyone who has done research investigating intelligent design or challenging global warming.

      Whenever politics and science intersect, it is science whose credibility suffers.

  6. there was a study that revealed chocolate was healthy for you,——it was later disclosed that the study was done by hershey’s ……

    • Such is the way of the modern world. if you want to argue for or against something, you commission an academic study (that will have a predetermined result) to support your position.This is the “greening” of academia. Bloomberg bought a whole graduate school of Public Health for a billion dollars, and you can be assured that it will do exactly what he wants it to do, ethics and honesty be dammed. It certainly brings the entire institution of higher learning into disrepute.

  7. It’s an age-old problem in the social sciences: too many degrees of freedom. Choose your study area. Choose your study period. Choose your dependent variable. Homicide rate not trending your way? Try narrowing it firearm homicide. No? Try all crime involving firearms. Still no joy? Throw in accidents and suicides, call it “firearm deaths.” Hell, if that doesn’t work out, try “fear of gun violence”. Still can’t find a correlation? Narrow the demographic. Look only at minority youth. Nothing? Try restoring it to males, or looking only at women. Reclassify some people old enough to drink as “children”. Not enough? Old enough to serve in Congress, then.

  8. Post hoc ergo propter hoc.

    That’s one of the very first things you need to account for in a study like this. This is stuff right out of a freshman level logic course. The fatal admission is that the assumption is that the reduction in the homicide rate is due only to the change in the law. That’s flat out question begging. By preemptively ruling out alternative explanations, they preordained their results.

  9. I think an earlier blog post covered this. The projected numbers are just out of thin air. I do like the excluded data sets which shows the law to be bogus.

  10. Hate distorts logic and reason, Bloomberg and the anti-Constitution groups will fail due to this. I always enjoy the time machine tarot card clairvoyance of “would have been”, statements. How John Hopkins finds the balls to put their name on bogus science is unethical secondary to the perception of medical facilities having the opposite expectation.

  11. Of course Bloomberg lied. It’s what they do. Lying is like breathing to a liberal fascist.

  12. You didn’t even mention the obvious gaming they did with their ‘weighting’ on synthetic Connecticut.

    For firearm homicides, 73% of the weighting of their ‘five state composite’ came from Rhode Island, presumably because Rhode Island had a spike in homicide rate (which doesn’t mean much given RI’s small population) for those important years after 1995. Then, to demonstrate the model “worked”, they compared non-firearm crime. Except they changed the weighting. Rhode Island no longer was weighted at 73% – instead, New Hampshire (originally weighted at 0.5% for the firearm homicides) was now weighted at 72%. Both weighting composites included at least two states that were weighted so lightly that they were mathematically insignificant to the final product (California, for example, was weighted at 0.00% for non-firearm homicide).

    What they did was build a model that *specifically was designed to showcase a similar firearm homicide rate before the gun law, and then spike aftewards*. This explains why their ‘synthetic Connecticut’ had a homicide rate spike higher than the national average – because Rhode Island itself had a spike in homicides that year. Since it was weighted so heavily, the homicide rate of ‘synthetic Connecticut’ skyrocketed. The problem is NO OTHER STATE IN THE COMPOSITE HAD THAT SPIKE, making their predictions of ‘what might have been’ utterly irrelevant.

  13. Facts & Logic have no place in an anti-gun study. It’s the narrative that matters. The feels.

  14. I love watching people rip apart these “studies”. Anyone who has taken a basic statistics or research methods course should see the problems immediately. The people who write these “studies” should be fired for incompetence. If you can’t even do statistics at a freshman level, how can you be a professor or doctor or study at a graduate level?

Comments are closed.