Is There a Contagion Effect When It Comes to Mass Shootings?

As of this writing, the last mass shooting in this country happened at a FedEx facility in Indianapolis. That was April 15, 2021, and so far, there has not been another. But based on how things have been going lately, we should not let out our breath just yet.

According to an April 21, 2021, report by NBC News, this year, there have already been seven mass shootings, defined as shootings in which three or more people have been shot. However, NBC counts shootings only in a public place. When including shooting events not in public, the number skyrockets to at least 45.

The report goes on to say the following:

There is a fear of more to come as COVID-19 restrictions are lifted. Pandemic-related trauma, an increase in gun violence, along with an increase in firearm sales throughout last year have been serious concerns for reopening, according to Jillian Peterson, an associate professor of criminology and criminal justice at Hamline University in St. Paul, Minnesota. 

Further, Peterson is quoted as saying:

We know that [these] types of mass shootings are contagious, that they tend to spread through things like the media and social media. People who are maybe vulnerable see themselves in other perpetrators who do this. [These are] people who already have their own history of trauma, who are perhaps feeling suicidal, who are in crisis, and who have access to weapons. They see someone make national headlines [by committing a mass shooting], which is this copycat effect.

The goal or wish to make headlines for some shooters may be more important than many realize. Peterson, who studies this type of violence, points to one shooting incident in Florida where the shooter went online to check the amount of media coverage he was getting during his 3-hour rampage.

However, the personal issues, why someone commits such a deadly act, is not our concern here. Instead, as the title of this post suggests, our focus is on whether these acts are contagious.

In other words, is there a direct line from the FedEx shooting to the six women of Asian descent shot in Atlanta to the grocery store shooting in Colorado and the four others so far this year?

While not definitive, the answer appears to this mass shooting question appears to be yes.

This is based on a study published in July 2015.* Titled Contagion in Mass Killings and School Shootings, the study concludes the following:

We find significant evidence that mass killings involving firearms are incented by similar events in the immediate past. On average, this temporary increase in probability lasts 13 days, and each incident incites at least 0.30 new incidents.

We also find significant evidence of contagion in school shootings, for which an incident is contagious for an average of 13 days and incites an average of at least 0.22 new incidents.

Finally, the researchers say:

On average, mass killings involving firearms occur approximately every two weeks in the U.S., while school shootings occur on average monthly. We find that state prevalence of firearm ownership is significantly associated with the state incidence of mass killings with firearms, school shootings, and mass shootings.

In other words, in those states where gun ownership is higher, so is the incidence of mass shootings in one form or another.

So, what can we do to protect ourselves? Here is what TAL Global suggests for our clients:

  • First and foremost, be aware that one shooting event may lead to another shooting.
  • Second, take extra security precautions for at least two weeks after a mass shooting.
  • And third, consider having a risk assessment conducted. This will help uncover weaknesses and vulnerabilities in your security and suggest ways to address them.

Click on the image below to Talk to Us. TAL Global is an elite security, consulting, and risk management firm that protects human and physical assets around the globe.   

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* Towers, Sherry, et al. “Contagion in Mass Killings and School Shootings.” PloS One vol. 10(7):e0117259. July 2, 2015. doi:10.1371/journal.pone.0117259

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