“The rate of mass shootings per 100,000 population has gone DOWN by an extraordinary degree.”

Though not a recurring pro-gun meme, this one was sent to the Gun Facts Project by someone from the pro-gun camp. It was an interesting claim, but incorrect. Investigating the claim then led us to dig and try to find underlying realities.

Seriously, the Gun Facts researchers need to get a life.

Mass Shootings Increase

Mass shooting incidents and fatalities are on the increase (and highly covariant with reported adverse reactions to prescription psychotropic medications). When we adjust for the increasing U.S. population, we still see per capita increases in the number of instances as well as the number of fatalities and woundings.

One thing jumped out at us from the initial charts, namely several outliers. Certain years showed dramatically large spikes. The most prominent of the spikes were the years of the Virginia Tech, Sandy Hook, Pulse Nightclub, Texas church and Las Vegas music festival shootings. The average number of fatalities of those events are 5.4 times larger than the average for all other events in the 21 century.

One hellish part of being a researcher is when you see an anomaly, you automatically ask “why?” This is followed by many hours of number crunching, chart making, and annoyed girlfriends.

What Made The Five Events So Fatal?

When we look at the five major U.S. mass shootings of the 21st century, we see the following events:

Virginia Tech: Students confined and purposefully trapped in classrooms – 32 dead (handguns).

Students confined and purposefully trapped in classrooms – 32 dead (handguns). Sandy Hook: Students trapped in classrooms – 27 dead (handguns, rifle, shotgun).

Students trapped in classrooms – 27 dead (handguns, rifle, shotgun). Pulse Night Club: People packed into a club with few exit paths (handgun, rifle).

People packed into a club with few exit paths (handgun, rifle). Texas First Baptist Church: People trapped and packed in a church (rifle).

People trapped and packed in a church (rifle). Las Vegas: People packed very tightly into a music venue with few escape paths (rifles).

As we noted in our original analysis of the Las Vegas concert massacre, the shooter had a near-perfect “cattle pen” situation. Any scenario where victims are immobile offers the potential for a higher body count. The reason is that marksmanship becomes less relevant, or even irrelevant. Simply firing into the crowd will result in deaths.

DEFINITION: A cattle pen scenario is defined as follows:

Many people in “crowded” area (required)

Limited exits or exit capacity (this and/or the next)

Few or no places to take cover (this and/or the previous)

A commonality of these events is the location. Certain locations – sadly, this includes schools – are ready made cattle pens. Indeed, when we look at just mass shootings by location, we see divergences. The chart here shows those location categories that had a significant slope calculation over the years, indicating a growing rate of fatalities (note: we dropped churches from the list because there are extended spans, as long as 15 years, with no church shootings, which confounds reliable trending analysis).

Naturally, this begs yet another question (creating more research and another highly annoyed girlfriend). What would we conclude if the spikes caused by pre-planned, cattle pen events were factored? With those major events included, we see an almost straight line escalation of fatalities in school shootings (we didn’t take the time to analyze the “other” category because the variety of such locations confounds the analysis, nor the “workplace” category since the trend in fatalities there was not significant to begin with).

When we remove the three cattle pen events from the list of school mass shootings, the trend changes substantially (and note, we left the Columbine High School massacre in the chart – the body count there was “only” twice as large as the 21 century, non-cattle pen average).

The Problem and Policy Point

Since half of mass public shootings involve only handguns or shotguns, we can discount the innumeracy hysteria sounding “assault weapons”. Also, when factoring away outlier events, we see that though worth worrying about, the rate of mass shooting events and the resulting carnage is not making a major escalation.

What is happening is that homicidal maniacs are learning.

We at the Gun Facts Project have (slowly) been reading on the topic of copy cat mass shootings and the alleged “media contagion” effect. For now we will simply say that testimony from surviving shooters and forensic evidence from those who did not survive shows that they spend copious amounts of time studying previous mass shootings. The Columbine massacre is the most studied event among the shooters that followed, and one aspect is that the pre-planning of this “cattle pen” event is formative. This was the mass public shooting that became the model for others.

One of the lessons that appears to have been learned by homicidal maniacs is that people densely packed into a confined area makes for a fertile killing field. Before Columbine, at least as far as the database used in this study goes, only three mass public shootings had a higher body count, and those were also similar to cattle pen events (San Ysidro McDonald’s, Luby’s Cafeteria and a post office work area). After Columbine, and the media contagion that followed, we see several high profile, high body count cattle pen events.

Given all of the above (no specific weapon type, no central age of the shooter, no similar backgrounds) the outlier events have the commonality of the cattle pen scenario. Given our love for big events and the ease of researching their murderous heroes online, we will likely see more consistent spikes of well-planned cattle pen massacres … at least until such time as the nation examines their mental health treatment choices.

A note on the data source:

In this analysis we used the Mother Jones database of mass shootings after we normalized it to conform with the criminology definition for mass public shootings, 4+ dead not including the attacker. The primary reasons for using Mother Jones’ database for this analysis was their including of a location category and that their database goes back further in time than others.

Update #1: Common vs Exceptional events

It is useful to identify a breakpoint between a “common” or “typical” mass public shooting, and this much larger “exceptional” incidents.

For our purposes, the number of 20 fatalities is our breakpoint, which we arrived at by charting all incidents from 1989 through earlier this week. As you can see in this chart, there is a clear division between the average body count of 6.9 fatalities and the much higher average of 34 dead in the “exceptional” category.

Update #2: A Cleaner Visualization

The original line chart in this post is quite useful, but it does not show the stark escalation of fatalities in mass public shootings in the post Columbine period.

Using spans of five years (semi-decadal) we see that before 2005, though the number of incidents rose and fell, the number of per capita fatalities stayed within a band.

After 2004, cattle penning events became more common, starting with the VA Tech massacre (32 dead), continuing in the next five-year span with Sandy Hook (27 dead) and onward into the current period with Pulse Nightclub (49), Las Vegas concert (58) and Texas church (26).