Mass Shooting Data Update, Ideas to Reverse the Trend

This is going to be somewhat of a duplication of my post from October on mass shooting data, but with more recent numbers. After the Las Vegas mass shooting, I felt the need to write sort of a capstone article summarizing material from the three previous posts. I also dedicated some space to venting my frustrations at politicians for doing absolutely nothing to help. After another tragedy, this time at Stoneman Douglas High School in Parkland, Florida, I started doing piecemeal updates to that October post. I finally realized it make much more sense to just update all the data in a new write-up. As I’ve said before, it’s not my intent to make this website political; for the most part this is an art sharing site, but I also post data analysis. And this is an important topic.

I won’t cover all the methodology again, but here are the basics. My primary sources are Mother Jones (MJ) and (GVA) mass shooting data tables, U.S. Census data, and my own open source research to fill in the gaps. MJ has great detail and multiple decades covered, but only lists major news items. GVA is more complete (literally everything with 4+ shooting victims), but only has the basic facts and public data for 3-4 years. So, each has it’s pros and cons. The general definition for a mass shooting is is “four or more shot and/or killed in a single event [incident], at the same general time and location, not including the shooter.

For a more detailed discussion on these data sources, see my last post, or the original parts 1, 2, and 3. I didn’t want to tread over that same ground again here, and instead get right into the data visualizations. I’ll start with some graphs split into two sections, then get into ideas to help mitigate this public health crisis.

Profile of Mass Shooters

Based on the data, the perpetrators of mass shootings are almost exclusively male, most of which have a history of mental illness. They commit these acts of violence almost equally in schools, businesses, or workplaces. They typically do not have a specific ideology, and are motivated either by a personal grudge or by other factors associated with severe mental illness. Weapons are usually obtained legally, and almost two thirds of the time involve a handgun (although rifles have increased in use over the last few years).

2.2018 mass shooting mental illness history of violence, MJ & Amdall

Figure 1. History of mental illness for shooter (left) and prior history of violence, from Mother Jones data, supplemented with open source research.

2.2018 mass shooting ideologies, MJ & Amdall

Figure 2. Ideology of mass shooting perpetrators, derived by me from the “Summary” and “Mental Health” fields in Mother Jones data, and from open source news when clarification was needed.

2.2018 mass shooting ideologies by year, MJ & Amdall

Figure 3. Ideology of mass shooting perpetrators by year, derived by me from the “Summary” and “Mental Health” fields in Mother Jones data, and from open source news as a supplement.

2.2018 mass shooting race and gender, MJ & Amdall

Figure 4. Mass shooting perpetrators by race/ethnicity (left) and by gender (right), from Mother Jones data.

2.2018 mass shooting venues, MJ & Amdall

Figure 5. Mass shooting venue types, from Mother Jones data.

Victim and Event Statistics

Mother Jones data (with open source supplements) show a steady increase in mass shooting events over the past few years, with an extremely high surge in total number of victims in 2017. Much of the increase in 2017 is attributable to the Las Vegas shooting, which was the worst I’ve seen from this data. GVA data does not include enough years to firmly establish a trend, but certainly appears to be increase in number of victims.

2.2018 mass shooting events per year, MJ & Amdall

Figure 6. Mass shooting events per year, from Mother Jones data, supplemented with open source research.

2.2018 mass shooting fatalities and victims per year, MJ & Amdall

Figure 7. Mass shooting fatalities and total victims (injured plus killed), from Mother Jones data, supplemented with open source research.

2.2018 mass shooting events and victims by year, GVA & Amdall

Figure 8. Mass shooting events per year (left) and fatalities and total victims (injured plus killed) per year (right), from data.

2.2018 mass shooting victims by state raw totals, GVA & Amdall

Figure 9. Raw total victim counts (killed and injured) in mass shootings by state, grouped into U.S. census regions, from and data.

2.2018 mass shooting victims by state per million, GVA & Amdall

Figure 10. Adjusted/per capita total victim counts (killed and injured) in mass shootings by state, grouped into U.S. census regions, from and data.

Possible Solutions

Is this specific category of gun violence getting worse? It certainly appears so. The question now is; what steps could we take to mitigate this? There is no single law that will eliminate gun violence, just like passing a law requiring seat belts didn’t stop all traffic deaths. We should approach the issue with as many solutions as possible, with a goal of chipping away at percentages and likelihoods until a large overall improvement is seen. Seat belts didn’t stop traffic deaths completely, but when combined with other measures, driving deaths were reduced over time. That’s the same approach I think the country needs to take with gun violence.

Here’s a list of measures that could be taken:

  • Extended waiting period. I’d like to see 30-60 days, but even 14 would be good.
  • Universal background checks. All firearm transactions should go through the National Instant Criminal Background Check System (NICS), with no loopholes for gun shows or private sales. In other words, if you want a firearm, you should have to go through an FFL-holding dealer. Absolutely no exceptions.
  • Close the background check time loophole. Apparently, if your background check isn’t complete before a three day deadline, you are automatically cleared to purchase a firearm. According to Time Magazine, in 2016 4,170 guns were sold to people with criminal records, mental illness, and other reasons that should have prevented them from buying a firearm because of this loophole. The change I’d like to see is that if the background check isn’t finished, you just have to wait longer.
  • Magazine limits. In some jurisdictions, high capacity magazines are defined as more than 10. But, some firearms have a standard capacity that is higher (15-18). Might have to settle for banning modifications beyond the manufacturer’s standard.
  • Limits and restrictions on firearm accessories. I’m not very knowledgeable about things like bump stocks and trigger cranks, but any method for increasing rate of fire should be included in the conversation.
  • National licensing. If a method of transportation can have federally mandated licensing, certainly tools made specifically to kill should be licensed as well. Perhaps states can administer them, as with driver’s licenses.
  • Mental healthcare improvements. Significantly increase funding for inpatient mental health facilities. Also, we need to seek the psych profession’s expertise in determining significant risk factors, disorders, and pathologies that tend to factor into subjects who commit mass shootings. Let’s get the professionals involved. Speaking of which…
  • Remove restrictions on the Centers for Disease Control. Since 1996, the CDC has been forbidden from conducting research on firearm fatalities, and from treating this epidemic of violence as a public health issue. In essence, the federal government has dropped it’s obligation to conduct meaningful analysis on the topic. It’s past time to reverse that. I shouldn’t have to worry about how complete GVA or Mother Jones data is; I should be able to go directly to the CDC for statistics, analysis, and studies on this topic.
  • Minimum purchase age of 21. There should probably be a personal use exception for law enforcement and military.
  • Domestic violence ban. If you abuse your spouse or children, you shouldn’t own a gun. My understanding is that a domestic violence conviction may be a reason for purchase denial, but anecdotally we seem to miss some of these abusers. (I’m not sure why; could be due to purchase loopholes, or maybe varied legal definitions?)
  • Reconsider an “assault weapon” ban. We had an “assault weapon” ban in place from 1993 to 2004. Since the ban’s expiration, mass shooting fatalities and victim totals have increased significantly. Although, according to Mother Jones data, only 29% of mass shootings involved a rifle (most offenders used handguns). Is the victim tally increase due to the proliferation of adaptable, military-style rifles? It’s hard to say for sure, and the exact definition of such weapons can be controversial, but it needs to be examined.
2.2018 mass shooting weapons, MJ & Amdall

Figure 11. Mass shooting weapon types used (left) and whether the weapons were obtained legally (right), from Mother Jones data.

2.2018 mass shooting weapons by year, MJ & Amdall

Figure 12. Mass shooting weapon types used by year. Initial data was from Mother Jones, but I had to supplement most incidents from 2014-2018 with open source research.

One of the major issues is that often, weapons used in mass shootings were obtained legally (see above graph). Dangerously unstable people were able to legitimately obtain firearms. Commentary then centers on why law enforcement didn’t prevent shootings, especially if there were troubling social media posts. The “hot take” is if officials are warned, they could have taken the person’s gun away or arrested them. It doesn’t work that way, though. An obsession with guns and angry/bizarre behavior doesn’t give law enforcement probable cause to arrest someone. There is a balance between protecting civil liberties and invasive activities of law enforcement, and some people seem to want it both ways. Additionally, our system for adjudicating mental illness is completely inadequate for evaluating these cases, so sometimes there is not a reliable mechanism for pre-emptive action.

None of these ideas are catch all fixes, obviously. Implementing one or all of these things won’t end violence, won’t stop all shootings. But it would provide law enforcement with more tools, and make some meaningful steps towards addressing the epidemic of mass shootings in America. As I said, we’re talking about taking multiple smaller steps to mitigate the issue; each measure alone may not do much, but combined they may reverse the trend. Certainly, it’s better than doing nothing again.

I’d like to stop seeing the Onion’s ‘No Way To Prevent This,’ Says Only Nation Where This Regularly Happens re-published every couple of weeks. Maybe we can make that happen in the next few years.

Previous posts on this topic:


  • Really informative – thank you!

    • Absolutely, I’m glad someone found it useful!

      My goal originally with this was to share what I found, where I found it, and how those resources differ on this topic. But after doing a few posts on it, I realized I was just complaining about a problem and offering nothing else. I had a boss many years ago who talked about being “solution oriented,” and I kept hearing his voice as I thought about this. So, hopefully adding ideas to fix the problem won’t turn away people who otherwise might be affected by/interested in this data

      • Yes, the solutions were good to read. The subject came up at work and some colleagues asked to read your post so I sent them the link (they’re not on WP).

      • Does it seem to you like the national dialogue is a bit different following this shooting? The tone seems a bit more urgent, or like more people are ready to take some action to address the issue. I hope that’s true, and it’s not just me being overly-optimistic

  • These posts are always so well organized and do a great job of breaking down the trends. They also hit me kinda hard. Really sad stuff.
    Personally I find the argument that eighteen year olds are too young to talk about gun violence to be ludicrous, since they can legally obtain an AR-15 in two days. Hopefully congress will stop playing games sometime in the foreseeable future.

    All the solutions you listed are reasonable and would be effective. I don’t understand why everyone is making reform so hard.

    • I agree, it can be really hard to think about this stuff, especially when it’s a school. I just can’t fathom being so against even minor inconveniences like a waiting period. Even if it means one less shooting, it’s worth it. Obviously what we’re currently doing isn’t working, so why not swing the pendulum back to some regulation?

      And you’re right, 18 year olds are definitely not too young to talk about it. In fact, they might be the perfect people to do it. They aren’t yet numbed by politicians’ slogans and TV talking points, and can speak from painful first-hand experience. I’ve been impressed with those kids from the Parkland high school, I’m glad they’re speaking up.

  • Excellent presentation of the statistics. I agree the response to the problem of mass shootings in the USA must be multifaceted. Since pharmaceutical prescriptions to teens for the treatment of depression and ADHD have consistently increased over the past 2 decades, we should also be examining possible links between drugs and violence. Thanks for taking the time to provide this information in an easily-digestible format.

    • Thanks Henry, I appreciate that.

      There are so many possible contributing factors, it’s hard to nail down. I hate to admit this, since I’m a consumer of it as much as anyone, but it’s also possible that the proliferation of violent media over the last couple of decades weighs in. If an angry, emotionally disturbed person has access to guns and has become desensitized to violence, that’s a recipe for disaster. It’s certainly only a piece, and I disagree with using it as a lone scapegoat (and as a way to deflect from gun control). Research doesn’t show a direct link between violent media and gun violence, but I believe they have shown a correlation with increased aggressive behavior.

      I still think the incredible proliferation of firearms in this country is the chief cause, though, even if there are other contributors. I’ve mentioned in other posts that I’m a firearm owner myself, so I’m not anti-gun. But, this idea of making it your identity, and becoming obsessed over weapons, doesn’t seem healthy to me.

      Anywho, I’m rambling at this point. Thanks for the comment, and I hope the CDC is unleashed to look at all possible factors, including those you mentioned.

      • Just to clarify my above comment a bit; there is no demonstrated causation between violent media/games and shootings. Playing video games doesn’t make people into mass shooters. But there is a fantasy element involved for people who commit these atrocities, and for emotionally/mental disturbed people, games or movies may help fuel them. We can’t look at this problem in terms of isolated factors; it’s complicated. It requires us to step back and examine what sort of societal incubator we’ve built that is so conducive to creating people like this.

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