The Data on Mass Shootings

By 

Best in Moderation

Mass shootings are back in the news, but they never really went anywhere. In fact, last year saw a major uptick in mass shootings, clocking in at 611 total incidents. 47 of those had 3 or more deaths.

There is a lot of data around mass shootings, but often enough discussions of them do not include the relevant data, instead banking on emotion, argument over cherry picked races, genders, types of guns, etc. I hope this serves as a bit of a primer for what I am sad to say will probably be many conversations about articles in the future.

To start off with, I’d like to define parameters. I’m going to only use data from several sources when I do comparisons and analysis. That doesn’t mean there isn’t an argument to be made for other comparisons; in fact, if you want to provide it, that can only be helpful for future discussions. Next, sources vary, so I will do my best to use only sources with direct possibilities to check, such as ones who link articles, databases, etc, or are the direct articles and databases themselves. Lastly, I will spend some time at the end debunking myths; I imagine this will be the source for a lot of debate below, but I’m going to make you wade through all the data first 

Sources being used:
https://www.gunviolencearchive.org/past-tolls
https://github.com/StanfordGeospatialCenter/MSA
https://www.motherjones.com/politics/2012/12/mass-shootings-mother-jones-full-data/
https://massshootingtracker.org/data/
https://worldpopulationreview.com/state-rankings/strictest-gun-laws-by-state

Mass Shootings General Data:

Mass shootings in 2019: 417
Total Dead: 465
Incidents with 3 or more dead: 54

Mass shootings in 2020: 611
Total Dead: 513
Incidents with 3 or more dead: 47

Mass Shooting State Details:

2019:

State	Rank (Total Incidents)	Rank (Fatalities)	Incidents	Fatalities	Injuries	Fatality / Incident	Injury / Incident	Population	% Population	% Mass Shootings	Gun Homicides	Gun Homicide Rate / 1M
California	1	2	49	65	49	1.33	1.00	39,512,223	12.04%	11.75%	159	4.02
Illinois	2	3	41	28	182	0.68	4.44	12,671,821	3.86%	9.83%	104	8.21
Texas	3	1	30	73	142	2.43	4.73	28,995,881	8.83%	7.19%	225	7.76
Louisiana	4	5	26	20	106	0.77	4.08	4,648,794	1.42%	6.24%	90	19.36
Maryland	5	13	21	12	85	0.57	4.05	6,045,680	1.84%	5.04%	68	11.25
Georgia	6	10	19	16	74	0.84	3.89	10,617,423	3.23%	4.56%	92	8.67
Pennsylvania	7	11	19	13	84	0.68	4.42	12,801,989	3.90%	4.56%	83	6.48
Missouri	8	6	18	20	60	1.11	3.33	6,137,428	1.87%	4.32%	77	12.55
Florida	9	7	15	20	54	1.33	3.60	21,477,737	6.54%	3.60%	169	7.87
Ohio	10	8	14	20	61	1.43	4.36	11,689,100	3.56%	3.36%	101	8.64
Alabama	11	9	12	17	47	1.42	3.92	4,903,185	1.49%	2.88%	81	16.52
New Jersey	12	14	11	12	47	1.09	4.27	8,882,190	2.71%	2.64%	32	3.60
North Carolina	13	12	11	13	40	1.18	3.64	10,488,084	3.20%	2.64%	77	7.34
Indiana	14	23	10	6	49	0.60	4.90	6,732,219	2.05%	2.40%	47	6.98
South Carolina	15	15	10	10	42	1.00	4.20	5,148,714	1.57%	2.40%	78	15.15
Virginia	16	4	10	21	41	2.10	4.10	8,535,519	2.60%	2.40%	49	5.74
Michigan	17	16	9	8	35	0.89	3.89	9,986,857	3.04%	2.16%	56	5.61
New York	18	20	9	7	43	0.78	4.78	19,453,561	5.93%	2.16%	45	2.31
DC	19	29	7	4	28	0.57	4.00	705,749	0.22%	1.68%	20	28.34
Tennessee	20	30	7	3	32	0.43	4.57	6,829,174	2.08%	1.68%	84	12.30
Arizona	21	21	6	7	26	1.17	4.33	7,278,717	2.22%	1.44%	41	5.63
Mississippi	22	17	6	8	21	1.33	3.50	2,976,149	0.91%	1.44%	43	14.45
Arkansas	23	31	5	3	20	0.60	4.00	3,017,804	0.92%	1.20%	24	7.95
Kentucky	24	24	5	6	18	1.20	3.60	4,467,673	1.36%	1.20%	30	6.71
Massachusetts	25	22	5	7	17	1.40	3.40	6,892,503	2.10%	1.20%	13	1.89
New Mexico	26	18	5	8	18	1.60	3.60	2,096,829	0.64%	1.20%	28	13.35
Colorado	27	33	4	2	20	0.50	5.00	5,758,736	1.75%	0.96%	25	4.34
Kansas	28	25	4	5	16	1.25	4.00	2,913,314	0.89%	0.96%	25	8.58
Oklahoma	29	26	4	5	12	1.25	3.00	3,956,971	1.21%	0.96%	32	8.09
Washington	30	19	4	8	12	2.00	3.00	7,614,893	2.32%	0.96%	31	4.07
Connecticut	31	35	3	1	12	0.33	4.00	3,565,287	1.09%	0.72%	13	3.65
Iowa	32	32	3	3	11	1.00	3.67	3,155,070	0.96%	0.72%	10	3.17
Nevada	33	36	3	1	12	0.33	4.00	3,080,156	0.94%	0.72%	22	7.14
Wisconsin	34	27	3	5	10	1.67	3.33	5,822,434	1.77%	0.72%	29	4.98
Delaware	35	38	2	0	10	0.00	5.00	973,764	0.30%	0.48%	10	10.27
Minnesota	36	37	2	1	12	0.50	6.00	5,639,632	1.72%	0.48%	15	2.66
Montana	37	28	2	5	4	2.50	2.00	1,068,778	0.33%	0.48%	9	8.42
Nebraska	38	39	1	0	4	0.00	4.00	1,934,408	0.59%	0.24%	9	4.65
Oregon	39	40	1	0	5	0.00	5.00	4,217,737	1.28%	0.24%	11	2.61
Wyoming	40	34	1	2	2	2.00	2.00	578,759	0.18%	0.24%	2	3.46
West Virginia	41	NA	NA	NA	NA	NA	NA	1,792,147	0.55%	NA	13	7.25
Alaska	41	NA	NA	NA	NA	NA	NA	731,545	0.22%	NA	10	13.67
Hawaii	41	NA	NA	NA	NA	NA	NA	1,415,872	0.43%	NA	10	7.06
Utah	41	NA	NA	NA	NA	NA	NA	3,205,958	0.98%	NA	7	2.18
Idaho	41	NA	NA	NA	NA	NA	NA	1,787,065	0.54%	NA	6	3.36
Maine	41	NA	NA	NA	NA	NA	NA	1,344,212	0.41%	NA	4	2.98
New Hampshire	41	NA	NA	NA	NA	NA	NA	1,359,711	0.41%	NA	3	2.21
Rhode Island	41	NA	NA	NA	NA	NA	NA	1,059,361	0.32%	NA	3	2.83
South Dakota	41	NA	NA	NA	NA	NA	NA	884,659	0.27%	NA	3	3.39
Vermont	41	NA	NA	NA	NA	NA	NA	623,989	0.19%	NA	2	3.21
North Dakota	42	NA	NA	NA	NA	NA	NA	762,062	0.23%	NA	0	0.00
TOTAL	999		417	465	1563	1.12	3.75	328239523			2220	6.76

2020:

State	Rank (Total Incidents)	Rank (Fatalities)	Incidents	Fatalities	Injuries	Fatality / Incident	Injury / Incident	Population	% Population	% Mass Shootings	Gun Homicides	Gun Homicide Rate / 1M
Illinois	1	1	69	42	301	0.61	4.36	12,671,821	3.86%	11.29%	105	8.29
California	2	2	39	37	153	0.95	3.92	39,512,223	12.04%	6.38%	209	5.29
New York	3	10	38	20	175	0.53	4.61	19,453,561	5.93%	6.22%	44	2.26
Florida	4	4	34	26	133	0.76	3.91	21,477,737	6.54%	5.56%	125	5.82
Pennsylvania	5	14	34	16	138	0.47	4.06	12,801,989	3.90%	5.56%	87	6.80
Texas	6	3	34	37	124	1.09	3.65	28,995,881	8.83%	5.56%	226	7.79
Louisiana	7	9	27	21	113	0.78	4.19	4,648,794	1.42%	4.42%	84	18.07
Ohio	8	8	25	22	111	0.88	4.44	11,689,100	3.56%	4.09%	85	7.27
Missouri	9	6	22	25	96	1.14	4.36	6,137,428	1.87%	3.60%	82	13.36
South Carolina	10	7	22	24	98	1.09	4.45	5,148,714	1.57%	3.60%	45	8.74
Michigan	11	11	20	19	72	0.95	3.60	9,986,857	3.04%	3.27%	84	8.41
North Carolina	12	5	20	26	80	1.30	4.00	10,488,084	3.20%	3.27%	83	7.91
Maryland	13	16	19	11	78	0.58	4.11	6,045,680	1.84%	3.11%	54	8.93
Tennessee	14	21	19	9	85	0.47	4.47	6,829,174	2.08%	3.11%	90	13.18
Georgia	15	13	17	18	73	1.06	4.29	10,617,423	3.23%	2.78%	98	9.23
Mississippi	16	12	17	19	70	1.12	4.12	2,976,149	0.91%	2.78%	40	13.44
Arkansas	17	19	13	10	48	0.77	3.69	3,017,804	0.92%	2.13%	33	10.94
New Jersey	18	17	12	11	51	0.92	4.25	8,882,190	2.71%	1.96%	24	2.70
Alabama	19	15	11	16	37	1.45	3.36	4,903,185	1.49%	1.80%	56	11.42
Colorado	20	25	11	6	52	0.55	4.73	5,758,736	1.75%	1.80%	20	3.47
Virginia	21	33	11	3	46	0.27	4.18	8,535,519	2.60%	1.80%	54	6.33
Kentucky	22	26	10	6	44	0.60	4.40	4,467,673	1.36%	1.64%	52	11.64
Wisconsin	23	18	10	11	42	1.10	4.20	5,822,434	1.77%	1.64%	31	5.32
DC	24	27	8	5	58	0.63	7.25	705,749	0.22%	1.31%	16	22.67
Massachusetts	25	28	8	5	33	0.63	4.13	6,892,503	2.10%	1.31%	11	1.60
Connecticut	26	23	7	7	27	1.00	3.86	3,565,287	1.09%	1.15%	14	3.93
Indiana	27	22	7	9	23	1.29	3.29	6,732,219	2.05%	1.15%	72	10.69
Minnesota	28	39	6	1	34	0.17	5.67	5,639,632	1.72%	0.98%	22	3.90
Washington	29	36	5	2	25	0.40	5.00	7,614,893	2.32%	0.82%	16	2.10
Arizona	30	31	4	4	16	1.00	4.00	7,278,717	2.22%	0.65%	44	6.05
Iowa	31	29	4	5	16	1.25	4.00	3,155,070	0.96%	0.65%	7	2.22
Nevada	32	24	4	7	12	1.75	3.00	3,080,156	0.94%	0.65%	22	7.14
Alaska	33	30	3	5	8	1.67	2.67	731,545	0.22%	0.49%	5	6.83
Delaware	34	34	3	3	11	1.00	3.67	973,764	0.30%	0.49%	13	13.35
New Mexico	35	40	3	1	12	0.33	4.00	2,096,829	0.64%	0.49%	18	8.58
West Virginia	36	20	3	10	7	3.33	2.33	1,792,147	0.55%	0.49%	28	15.62
Kansas	37	44	2	0	9	0.00	4.50	2,913,314	0.89%	0.33%	17	5.84
Nebraska	38	37	2	2	10	1.00	5.00	1,934,408	0.59%	0.33%	5	2.58
Oklahoma	39	41	2	1	7	0.50	3.50	3,956,971	1.21%	0.33%	16	4.04
Oregon	40	42	2	1	7	0.50	3.50	4,217,737	1.28%	0.33%	20	4.74
Idaho	41	38	1	2	3	2.00	3.00	1,787,065	0.54%	0.16%	7	3.92
Maine	42	35	1	3	1	3.00	1.00	1,344,212	0.41%	0.16%	1	0.74
South Dakota	43	43	1	1	3	1.00	3.00	884,659	0.27%	0.16%	4	4.52
Utah	44	32	1	4	1	4.00	1.00	3,205,958	0.98%	0.16%	11	3.43
Hawaii	45	45	0	0	0	NA	NA	1,415,872	0.43%	NA	2	1.41
Montana	45	45	0	0	0	NA	NA	1,068,778	0.33%	NA	9	8.42
New Hampshire	45	45	0	0	0	NA	NA	1,359,711	0.41%	NA	2	1.47
Rhode Island	45	45	0	0	0	NA	NA	1,059,361	0.32%	NA	4	3.78
Wyoming	45	45	0	0	0	NA	NA	578,759	0.18%	NA	1	1.73
North Dakota	46	46	0	0	0	NA	NA	762,062	0.23%	NA	0	0.00
Vermont	46	46	0	0	0	NA	NA	623,989	0.19%	NA	0	0.00
TOTAL	999		611	513	2543	0.84	4.16	328239523			2198	6.70

Mass Shooting Demographics

Average Age of Mass Shooter: 34
Age Range Mass Shooter: 11 – 66 (5% under 18)
Percent showing clear prior indications of violence: 50.4%
Incidents where weapon was legally obtained: 69.7%
Incidents wherein weapon was limited to handguns: 10%
Most Common Guns: Glock 17, AR-15
Perpetrators by race: White (55.46%), Black (19.65%), Latino (8.4%), Asian (6.72%)
Perpetrators by biological sex: Male (97.5%), Female (2.5%)
Event vs Spree Ratio: 84% / 16%

Mass Shooting Claims:

1. Mass shootings occur in states with the most gun ownership
2. Mass shootings drop with more restrictive gun laws
3. Mass shootings are disproportionately perpetrated by white men
4. Mass shootings correlate to the state gun homicide rate
5. Mass shootings are proportional to the population
6. Mass shootings are often done by those with mental illnesses

1. Mostly, no. Out of the top 5 states for gun ownership, none rank even in the top 15 for mass shooting incidents. Lower gun ownership does show some impacts, with two of the lowest 5 having no mass shootings. However, New York, ranked 3 in mass shootings, has the 3rd lowest ownership of guns, thus becoming an outlier for this. Possible explanations can be that gun ownership reporting is lax, and that 30% of guns used in incidents are obtained illegally, but more study would have to be done to see if this explains the outlier in New York. Either way, the claim that lower gun ownership = lower incidents has some support, but higher gun ownership = higher incidents does not.
   
   
2. Again, the data here is a mixed bag. California, rated most restrictive, has the 2nd highest mass shooting incident rate. New Hampshire, with the 2nd most restrictive laws, has the least mass shooting incident rate. The rest of the top 5 range around. Conversely, there doesn’t seem to be any pattern at all to lowered gun restrictions impacting mass shooting incidents; the range is similar, albeit not so obvious as with CA and NH. This claim too seems to be a myth.
   
   
3. As far as biological sex goes, yes, mass shooters are overwhelmingly likely to be men. As far as race goes, there are more perpetrators who are white or black, and less that are latino and Asian, than would be expected based on demographics. The difference isn’t much though, so claiming that being white is a good indicator is not very true. Male = yes, white = no.
   
   
4. Both Louisiana and Missouri fall into the top 5 in gun homicides and top 10 in mass shootings. Conversely, all the lowest gun homicide states appear on the bottom of the incident list. So while it is not a 1:1 relationship, this is somewhat correlated. Interestingly though, the top 5 mass shooting rate states fall pretty much average in other gun homicides. I’d say this is mostly a myth on the extremes, but shows some statistical tendency (which is to be expected, since mass shootings are a part of total homicide statistics).
   
   
5. The top 7 populated states directly link to the top 7 mass shooting incident states, with one exception. Louisiana has only 1.42% of the population but 4.42% of the mass shootings. Interestingly, when you look at the RATE of shootings, a different picture emerges. While CA has 12% of the population, it only has 6.4% of the mass shootings, so it’s share is far below what it should be. This holds true for Texas as well, and to a lesser extent Arizona and Washington. On the flip side, Illinois has 3.86% of the population but 11.29% of all mass shootings, similar to Louisiana and South Carolina, and to a lesser extent Mississippi, Missouri and Pennsylvania. So while nominally the claim is true, as a rate it certainly is not, with several states showing exception.
   
   
6. Not really. Less than 30% of perpetrators of mass shootings had any indications of mental illness, and fewer still were diagnosed (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4318286/). Mostly it’s triggering events that put stress on them, activating their fears. This is why misinformation and conspiracy theories are so dangerous; they tend to be the basis for mass shooting actions.

Summary:

There is a lot to go over when we discuss gun violence in general. Too much to cover in one OP. So I hope this limited data dump of mass shooting information helps to keep the conversations factual and meaningful.

Please ask questions and pose other claims you’d like to see discussed below.

Gun Violence Research Remains Neutralized

Spitting hot lead in defense of America, mom, 

apple pie, the flag, automatic weapons, ammo, etc.

The use of illicit drugs and a history of physical fights in the home are important risk factors for homicide in the home. Rather than confer protection, guns kept in the home are associated with an increase in the risk of homicide by a family member or intimate acquaintance. .... Our data indicate that keeping a gun in the home is independently associated with an increase in the risk of homicide in the home. The use of illicit drugs and a history of physical fights in the home are also important risk factors. -- Arthur L. Kellermann, et al., New England Journal of Medicine, 329:1084-1091, Oct. 7, 1993

“The Gun Lobby’s interpretation of the Second Amendment is one of the greatest pieces of fraud, I repeat the word fraud, on the American People by special interest groups that I have ever seen in my lifetime. The real purpose of the Second Amendment was to ensure that state armies – the militia – would be maintained for the defense of the state. The very language of the Second Amendment refutes any argument that it was intended to guarantee every citizen an unfettered right to any kind of weapon he or she desires.” – conservative Chief Supreme Court Justice Warren Burger

In an average year, gun violence in America kills nearly 40,000 people, injures more than twice as many, and costs our nation $280 billion. .... examining the serious economic consequences of gun violence is paramount to understanding just how extensive and expensive this crisis is. .... On an average day:

• American taxpayers pay a daily average of $34.8 million for medical care, first responders, ambulances, police, and criminal justice services related to gun violence.
• Employers every day lose $1.4 million in productivity, revenue, and costs required to recruit and train replacements for victims of gun violence.

CONTEXT

In 1996, congress effectively banned federal funding for gun violence research. The ban was a response by people who opposed gun regulation and the NRA to a 1993 research paper (quoted above) that shows that gun ownership was a risk factor for domestic homicide. That unsurprising result sent the gun people into a crazed frenzy of fear and rage. As usual, the inconvenient research paper was smeared by partisan propaganda. It was falsely characterized as a political attempt to take away everyone's guns. Once again, inconvenient science and truth was politicized and lied about for ideological and special interest reasons, mostly gun industry profit. That came at the expense of the public interest, in particular, public safety.

The ban came in the form of a law that barred the CDC from spending money to “advocate or promote gun control.” Over the years, the NRA and others justified keeping the ban in place in the face of attempts to get it removed. The justifications included lies such as (i) the CDC does not have the expertise to get involved in gun violence research, and (ii) the research is being done in other federal agencies. When ideology and/or big money is at stake, inconvenient facts and truths are shamelessly obliterated by lies and slanders for political partisan reasons in congress and for special interest profit.

The situation in 2021

An article in the New York Times, Can New Gun Violence Research Find a Path Around the Political Stalemate?, curiously suggests that the research funding ban is still in effect while actually saying it isn't. Maybe this is the NYT's attempt to help get the funding ban removed. Who knows? The NYT writes:

And Andrew R. Morral, a behavioral scientist at the RAND Corporation, a research group, is using sophisticated modeling tools to estimate rates of gun ownership in every state, with detailed demographic information. The purpose, he said, is to search for patterns in firearm homicides and suicides — a first, basic step in research that could lead to reducing them.

The recent mass shootings in Atlanta and Boulder, Colo., have once again left Democrats and Republicans in a stalemate over background checks for gun buyers and assault weapons bans. But public health experts say a new round of research could pave the way for gun policies that avoid partisan gridlock — and ultimately save thousands of lives.

The studies by Dr. Naik-Mathuria and the others are being paid for by the Centers for Disease Control and Prevention, which is once again funding research into gun violence after a nearly 25-year hiatus imposed by Congress. And while they might not reduce the number of massacres, mass shootings account for an extremely small percentage of the roughly 40,000 Americans who die each year from gun violence.

“It’s not either, ‘Keep your guns or prevent gun violence,’ ” said Dr. Mark Rosenberg, who helped establish the C.D.C.’s National Center for Injury Prevention and Control but said he was fired in the late 1990s under pressure from Republicans who opposed the center’s gun research. “There’s a strategy that science can help us define where you can do both — you can protect the rights of law-abiding gun owners and at the very same time reduce the toll of gun violence.” 

Federal money for gun research all but disappeared after Congress in 1996 enacted the so-called Dickey Amendment, which barred the C.D.C. from spending money to “advocate or promote gun control.” It was named for Jay Dickey, a former Republican House member from Arkansas, who proudly proclaimed himself the National Rifle Association’s “point man” in Washington.

In 2019, Dr. Rosenberg and Mr. Dickey’s former wife, Betty, a retired former prosecutor and chief justice of the Arkansas Supreme Court, helped persuade Congress to restore the funding; lawmakers appropriated $25 million, split between the C.D.C. and the National Institutes of Health, for firearm injury prevention research.

The agencies are now financing nearly two dozen studies, though backers of the research say the money is a pittance compared with the breadth of the problem. (emphasis added)

Inflicting righteous discipline on the miscreants,

you know, democrats, atheists, the LGBQNT folks, 

undocumented immigrants, 

people shopping for groceries, etc.

There's nothing like a good NRA point man in Washington to make sure that greedy, corrupt special interests get what their campaign contributions paid for. Before he died in 2017, Dickey expressed surprise and regret about banning the research money. He defended himself as saying something along the lines of: 'Gosh 'n golly, shucks, gee wiz, holey moly! I never intended to stop all the research. I just wanted to stop all the political stuff.' Maybe Dickey actually drank the cool-aid the NRA bought for him and was sincere, or maybe he was just another cynical lying politician.

So, here we are today, about 25 years later and still ignorant about gun violence and politically gridlocked. We are still ignorant about possible ways to reduce it without unduly burdening a fraudulent right to bear arms. And we are still suffering mass shootings by freaks, mostly enraged males, exercising their fraudulent right to bear weapons of mass slaughter.

Come and take it?? That's feisty!

Careful, don't grab the wrong pussy!