Gun control advocates this month took a page from the global warming activists playbook: the science is settled, so there is no need for debate.

However, instead of actually reviewing the scientific literature on the subject, Professor David Hemenway at Harvard made a survey of cherry-picked authors.  Surprisingly, he found the vast majority agreed that we need more gun control.

So let’s look at the details.  He polled authors who had published in the fields of “public health, public policy, sociology, or criminology.”  Most notably, half of the authors picked were within Hemenway’s own field of public health and another third were sociologists/criminologists, followed by public policy and a few economists. It dramatically over weighted those in public health.  It didn’t matter whether the publications even contained any empirical work or were related to the survey questions.

Authors were asked if they agreed with the statement: "In the United States, guns are used in self-defense far more often than they are used in crime.”  Hemenway reports that 73 percent disagreed.  However, many respondents may have believed that there still exists a net benefit from gun ownership — just not enough to say that guns are used defensively “far more often.”

It is abundantly clear that it matters who you ask and how the questions are asked.  A survey released in February by the Crime Prevention Research Center conducted by Professor Gary Mauser at Simon Fraser University in Canada found that 88 percent of North American economics researchers agreed with the statement that, in the US, guns were more frequently used for self-defense than for crime.  

Other questions were posed by Hemenway in ways to hide information.  For instance, respondents were asked to evaluate: "The change in state-level concealed carry laws in the United States over the past few decades from more restrictive to more permissive has reduced crime rates.”  62% of respondents claimed that there wasn’t a benefit from concealed handgun laws and the Boston Globe ran this headline: “Most gun experts believe guns do more harm than good.”  

In contrast, Professor Mauser asked researchers whether they thought permitted concealed handgun laws either reduced murders, had no effect, or increased murders.  Among North American economists, 81 percent stated the laws reduced murders, 19 percent that they had no effect. Absolutely no one said that the laws increased crime. If economists outside of North America were included, the results changed slightly, with 74 percent stating the laws reduced murders, 20 percent that they had no effect, and 6 percent that they caused an increase.

Sixty percent of respondents in Hemenway’s survey agreed that "evidence indicates that background checks can help keep guns out of the hands of a significant number of violent people.”  But only 31% of all those surveyed thought that the evidence was either strong (24%) or very strong (7%).  And even these numbers seem unrealistically high.  Study after study by criminologists and economists find that background checks have no effect on crime rates.  

Economists have done a lot of work on crime.  Unlike the vast majority of work in public health, it is usually much more rigorous with more detailed statistical evidence dealing with issues of causality. Economists are also much more open to the notion of deterrence than the vast majority of authors surveyed by Hemenway.  I myself was chief economist at the United States Sentencing Commission.  But Hemenway steers away from economics journals.  In addition, looking at publications from only 2011 through 2013 also picks up a recent surge in public health studies and skews the sample towards those types of authors.

I was included in the list of those surveyed, but when I emailed Hemenway reporting that my responses weren’t be recorded, my emails were ignored.

Ironically, despite over 300 studies on firearms published over about three years, Hemenway frequently complains that firearms researchers just aren’t getting enough money.

If you want to know what researchers think about gun control, simply read their research.  Yet, Hemenway is right on one point: on questions such as concealed carry laws, the debate is as good as over.  The vast majority of studies show that these laws reduce crime. And there are no refereed journal articles by economists or criminologists claiming that concealed handgun permits increase murder, rape or robbery.

John R. Lott, Jr. is a columnist for FoxNews.com. He is an economist and was formerly chief economist at the United States Sentencing Commission. Lott is also a leading expert on guns and op-eds on that issue are done in conjunction with the Crime Prevention Research Center. He is the author of nine books including "More Guns, Less Crime." His latest book is "The War on Guns: Arming Yourself Against Gun Control Lies (August 1, 2016). Follow him on Twitter@johnrlottjr.