The main change I've made has been to add a column indicating whether the shooter was a U.S. military veteran. I've also deleted some of the shooting incidents, reducing the list from 111 to 97 shootings. I've done this, just as I had done previously, in order to be able to make an accurate comparison to the general population. Relatively few women are veterans or shooters, and the incidents of shootings by women seem too few to draw comparisons from. Looking at men only, the percentage who are veterans in the U.S. population varies dramatically by age group. So, I've removed shootings by women or by men under 18 or over 59. I've also deleted one shooting that was an attack on the U.S. military by a foreign-born shooter, as it seems irrelevant to ask if that shooter had been in the U.S. military. As blowback, however, that shooting involved the U.S. military as much as any other.
Looking at the 97 shootings in the remaining database, I've marked 34 of them as being committed by U.S. military veterans. In two cases, this indicates a veteran of JROTC, one of whom may or may not have had further participation in the military. These two were trained in shooting at public expense by the U.S. military, although at least one of them was not yet a member of or veteran of the military. I have not included as veterans shooters who had been security guards or prison guards. I have not included as veterans shooters who were on record describing their future crime in explicitly military terms as if participating in and referencing by name the U.S. military, unless I could determine that they had actually been in the U.S. military. I have left on the list of 97 a small number of foreign-born shooters, who may or may not have been trained by foreign militaries, and some of whom could not have legally joined the U.S. military; none of these are among the 34 marked as veterans. Also among the 97 are at least two men who tried to join the U.S. military and were rejected; they are not counted among the 34 veterans. At least one among the 97 worked at a U.S. Navy base but not as a member of the U.S. military; he is not counted as a veteran. Most significantly, I have not been able to determine military status one way or the other for the majority of the shooters on the list; it is entirely possible that more than 34 were military veterans. The 34 marked as veterans are simply those I could determine were veterans by reading news reports.
The result of all this is that, with this updated database, 35% of U.S. mass shooters (lone, male, 18-59) are veterans, whereas 14.76% of the general population (male, 18-59) are veterans. A mass shooter is 2.37 times more likely to be a veteran than a random person is.
Needless to say, or rather, I wish it were needless to say, but I have to say it in every interview, veterans vastly outnumber mass shooters. Most veterans virtually all veterans are NOT mass shooters. Similarly, those with mental health issues vastly outnumber mass shooters. Virtually all people with mental health problems, or all men who've abused women, or all males, or all gun owners, are NOT mass shooters. The facts that ought to dissuade people from bigotry or profiling are painfully obvious, even if only selectively required.
Needless to say, or rather, I wish it were needless to say, more than one contributing factor to mass shootings can be worth addressing.
Needless to say, or rather, I wish it were needless to say, people inclined toward mass shootings could simply also be inclined to join the military, making the relationship a correlation and not a cause. In fact, I would be shocked if there weren't some truth to that. But it's also possible that being trained and conditioned and given a familiarity with mass shootings and in some cases an experience of engaging in mass shooting and having it deemed acceptable or praiseworthy makes one more likely to mass shoot. I cannot imagine there isn't truth in that.