As the debate on gun safety continues, it is wise to listen carefully to evidence cited on either side of the argument. On Friday, the Washington Post awarded three Pinocchios to Bill Clinton for his recent ‘facts’ on mass shootings.

Bill Clinton stated, “Half of all mass killings in the United States have occurred since the assault weapons ban expired in 2005, half of all of them in the history of the country.”

That is not totally true. The article reports:

With gun shootings, you immediately get into some definitional issues. Depending on how one defines a “mass public shooting,” the answers might turn out to be different. There is also surprisingly little historical data about mass murder in the United States to go back all the way to the nation’s founding.

Grant Duwe, director of research and evaluation at the Minnesota Department of Corrections, assembled a data set going back 100 years for a 2007 book titled, “Mass Murder in the United States: A History.” He used the FBI Supplementary Homicide Reports, which date from 1976, and then supplemented the FBI reports with news reports (principally The New York Times) dating from 1900.

Duwe says the Times turned out to be a relatively reliable guide for mass murders across the country, since much of the post-1976 information also turned up in the contemporaneous FBI reports. As far as he knows, he is the only person who has assembled such a historical data set.

According to his research, he has identified 156 mass public shootings in the United States in the past 100 years.

…Since 2005, when the assault ban expired, there have been 32 such mass public shootings, including seven in 2012, Duwe said. So that’s just over 20 percent of all mass public shootings, which is much less than Clinton’s 50 percent.

There are a few things to keep in mind as this discussion continues. First of all, how many of these murders were committed by people who legally owned the guns they used? How many of these mass murders were committed in ‘gun free’ zones? How many of these murders had a past history of mental illness or had people around them who were not shocked at what they had done? How does our society treat and handle the mentally ill? Can any government stop an insane person from doing something insane?

Stay close to a good fact checker as the debate continues.