On average in the US, is there a mass shooting 9 out of every 10 days?

Reading the New York Times today, I came across this very amusing "tourism video" touting the benefit of visiting/moving to Australia, namely, "You Won't Get Shot".

Don’t Get Shot in America. Live in Australia!

At ~1:25, the actor states,

In your United states, on average, there's a mass shooting 9 out of every 10 days. But here in Australia, we just go to the beach... without getting shot.

Googling this, I found that there's no "official" or universally accepted definition of "mass shooting". Clearly, gun control advocates favor a loose definition: a shooting in which at least four people are injured or killed in one location, not including the suspect. This is the definition proposed, per Nancy Pelosi's spokespersons, by Gun Violence Archive, though I could not find that definition on skimming.

A tighter definition, used in the July 2015 Congressional Research Service Report (CRSR) is "a multiple homicide incident in which four or more victims are murdered with firearms, within one event, and in one or more locations in close proximity." This definition does not seem to exclude the shooter (I might be wrong.)

In any case, the CRSR numbers are nowhere near the number claimed in the "Australian" don't get shot video, but only includes data to 2013.

Is there any truth to the NYT video's claim?

• Comments are not for extended discussion; this conversation has been moved to chat. Commented Aug 23, 2018 at 6:52

3 Answers

I've written about the issues with defining a "mass shooting" in another answer previously. I'm going to copy and paste the pertinent parts here.

The main problem with statistics like these is that there is no one definition of "mass shooting" and thus, by adjusting your parameters, can make the number be whatever you want to fit a narrative. Depending on the definition you wish to choose for a "mass shooting", the percentage for the quoted statistic can range from 2.6 every 100 days to 97.4 per every 100 days.

What is a mass shooting? There are some events, like the Stoneman Douglas High School shooting, the 2017 Las Vegas shooting, and the Columbine High School massacre, where everyone can agree that it should be considered a mass shooting.

But what about this incident in Saginaw, Michigan, where 5 people were shot at a house party and no one was killed? Or this event in Madison, Alabama, where 4 people were shot and no one was killed?

The Wikipedia article on Mass Shooting points out the huge issue in the definition of Mass Shootings.

The term was originally defined as the murder of four or more people with no cooling-off period but redefined by Congress in 2013 as being murder of three or more people. According to CNN, a mass shooting is defined as having four or more fatalities, not including gang killings or slayings that involve the death of multiple family members. In "Behind the Bloodshed", a report by USAToday, a mass killing is defined as any incident in which four or more were killed and also includes family killings. A crowdsourced data site cited by CNN, MSNBC, The New York Times, The Washington Post, The Economist, the BBC, etc., Mass Shooting Tracker, defines a mass shooting as any incident in which four or more people are shot, whether injured or killed. As of November 2017, the FBI defines a mass shooting as an incident involving "four or more people shot at once." A noteworthy connection has been reported in the U.S. between mass shootings and domestic or family violence, with a current or former intimate partner or family member killed in 76 of 133 cases (57%), and a perpetrator having previously been charged with domestic violence in 21.

The lack of a single definition can lead to alarmism in the news media, with some reports conflating categories of crimes.

PolitiFact agrees that there's a huge issue with that definition. In a 4 October 2017 article titled "How is a ‘mass shooting’ defined?", PolitiFact refuses to rate a claim by House Minority Leader Nancy Pelosi where she claimed

"273 mass shootings in 2017 -- one for each day of the year."

PolitiFact, before getting into the meat of the article, includes this sentence.

We are not rating her claim on our Truth-O-Meter, however, because our current research indicates the debate over the definition of mass shootings is more unsettled than ever.

They continue along in the article as if it was another fact check, although without an actual rating.

Pelosi’s spokesman told us the congresswoman’s number comes from the Gun Violence Archive, a crowdsourcing website that tracks gun deaths using media reports. It defines a mass shooting as one in which at least four people are injured or killed in one location, not including the suspect.

The Gun Violence Archive listed 273 mass shootings as of Oct. 1, 2017, the day of the Las Vegas massacre.

(...)

Pelosi’s claim and the mass shooting definition it rests on ignores strict criteria developed in a July 2015 Congressional Research Service report. It defines a mass shooting as "a multiple homicide incident in which four or more victims are murdered with firearms, within one event, and in one or more locations in close proximity." The report has been frequently cited by some criminologists and gun rights advocates.

Criminologists who spoke with PolitiFact in the past say this definition was more in line with events such as the shootings at Columbine, Virginia Tech or in San Bernardino.

They also told PolitiFact that the Gun Violence Archive’s tally includes far more than what would be considered mass shootings because it lumps in gang shootings and home invasion robberies.

As PolitiFact Florida reported in 2015, "Politicians or others who want to make a point about guns choose a set of data and a definition that reinforces the point they want to make. People who want more gun control tend to choose more expansive definitions." (emphasis mine)

PolitiFact continues by explaining that many criminal experts have their concerns even with these definitions.

Gun control groups say it’s arbitrary to distinguish between a death and an injury. They point out a significant problem: Some shootings that injure a dozen or more people but don’t kill four people would not be considered a mass shooting under the more restrictive definition.

"I would submit that sometimes the only difference between a shooting and a murder could be a centimeter, an inch, an unlikely ricochet, whatever," Bueermann, who now is president of the Police Foundation, which researches law enforcement practices, told the Post. "If we're trying to capture true gun violence in our country, a broader definition [of mass shooting] is probably more useful than a narrow one."

(Frederic) Lemieux went on to say the broad definitions of mass shooting remain problematic, citing the inclusion of crimes such as familicide, where "victims are exclusively family members and not random bystanders."

"Gang murders are usually crime for profit or a punishment for rival gangs or a member of the gang who is an informer. Such homicides don’t belong in the analysis of mass shootings," he added.

Gun Violence Archives brings this into greater clarity with their statistics for 2018. They use the "4 or more injuries" criteria to define a mass shooting. By this count, they have 103 mass shootings as of 24 May 2018. However, by using the more strict definition of "four or more victims murdered with firearms, within one event, and in one or more locations in close proximity", the count is at most 10. However, of the 10 you have

With the exception of the two school shootings, the Waffle House shooting, and the Car Wash shooting, many of these wouldn't even be considered mass shootings under this more restrictive definition. Some only hit the 4 deaths mark due to including the shooter, some take place in multiple locations, some involve family members, and some are possibly gang-related.

In terms of this claim by the actor, if we were to use the loosest definition of "mass shooting" (4 or more victims, not necessarily killed, and can be of any relation to the shooter), the statistics are actually worse for 2018. Gun Violence Archive has 227 mass shootings for 2018 as of 21 August 2018. As 21 August 2018 is the 233rd day of the year, the odds of there being a "mass shooting", using the most liberal definition of "mass shooting", is actually

227 / 233 = 97.4%.

However, we can also use the much more restrictive definition of "mass shooting" (4+ deceased victims excluding the subject/suspect/perpetrator, one location). Gun violence archive uses the tag "Mass Murder" for these types of events. Using this more restrictive definition, we get a total of 12 events, and the odds now become

12 / 233 = 5.2%

If you also require it to be one location, we can exclude 2 of the 12 events due to them being in multiple locations.

10 / 233 = 4.3%

And by requiring the even more restrictive definition of it not being gang/drug/family related, you can exclude 3 (and possibly 4) additional events.

7 / 233 = 3.0%

6 / 233 = 2.6%

Because the definition is so unsettled and no one can seem to agree on what the definition should be (or even if there should be a set definition in the first place, as seen in this event which is not included in the restrictive statistics in spite of the fact that 16 people were shot), you can settle on whichever definition fits your worldview and claim any statistic that you want.

Now, it is impossible to know exactly what methodology they are using to calculate the "9 out of every 10 days" number, but by changing your definitions, you can certainly create that number.

• @medica essentially, you are correct. There isn't a definition of mass shooting that people can agree with, and as seen in the bottom portion of my answer, using the least restrictive definition of "mass shooting" generates a statistic that is actually worse than the one you quoted in your question. Commented Aug 21, 2018 at 21:03
• The actor only makes the claim that you won't get shot rather than 'shot and killed'. So for the wording of the advert it seems reasonable to use the looser definition. Commented Aug 23, 2018 at 8:54
• There is a difference between "average number of mass shootings per day" (227 / 233 = 0.97) and "number of days with at least one mass shooting", which is lower. If 227 mass shootings happen randomly in a period of 233 days, we should expect 145 days (62%) with ≥ 1 shooting and 88 days with 0 mass shootings, so 90% is likely wrong even with the most inclusive definition of mass shooting. Commented Aug 23, 2018 at 9:46
• @DenisS “There's on average 9 mass shootings per 10 days” (correct) is different from “on average, there's a mass shooting 9 out of every 10 days” (incorrect). The average number of days with at least one mass shooting is lower than that. The second version is like saying that on average, there's 365 days per year with snowfall, because the average snowfall per day is 1 mm (for a location assuming 36.5 cm/year snowfall), which would also be wrong. Commented Aug 23, 2018 at 14:41
• @gerrit at this point you're trying to argue semantics by moving words around. You may want to interpret it that way, but many people here (including the excellent BobTheAverage answer) have interpreted it differently. Sure, you could interpret it as "days with 1+ mass shootings" to get the number you choose, but that's exactly the point of my answer, that you can adjust your definitions and play with words however you want to make the numbers say whatever you want. Commented Aug 23, 2018 at 18:47

It depends on the definition.

This article in Mother Jones says:

Studies indicate that the rate at which public mass shootings occur has tripled since 2011. Between 1982 and 2011, a mass shooting occurred roughly once every 200 days. However, between 2011 and 2014 that rate has accelerated greatly with at least one mass shooting occurring every 64 days in the United States.

This source defines mass shootings as:

...attacks that took place in public, in which the shooter and the victims generally were unrelated and unknown to each other, and in which the shooter murdered four or more people. Source

This is far lower than the rate quoted in the video. The work was published through Mother Jones, which is a very liberal, pro gun control publication.

That article criticizes another study by James Alan Fox which counts 20 or so a year. Fox defines a mass shooting as one in which four or more people die, regardless of the surrounding circumstances.

By contrast ShootingTracker.com lists 346 incidents in 2017 in which 4 or more people were shot. This matches the claim of shootings on 9 out of 10 days. Of these incidents, 24 fit Fox's definition of 4 or more killed. There is a certain literalness to this definition. We say mass shooting, not mass killing.

The Gun Violence Archive, which maintains ShootingTracker.com, has a page outlining their methodology. In my non-expert opinion, the methodology seems fairly sound for validating this particular claim. "GVA has a dedicated, professional staff which sweeps law enforcement and media resources daily and logs incidents."

In response to the ridiculously frequent comment that: "There's a mass shooting 9 days out of 10" is different from "there's an average 9 mass shootings per 10 days"

The actual claim includes the word average, which makes the claim somewhat ambiguous. Consider one week with 7 mass shootings on Monday, and another week with one mass shooting every single day. From a policy standpoint, the distinction between these two is pointless. The same number of people got shot. The mods keep deleting these comments because they add nothing to the discussion.

Conclusion:

In 2017 there were 346 incidents in which 4 or more people were shot. This is an average of 0.94 per day, higher than the 0.9 per day in the claim. There were 24 incidents in which 4 or more people were killed, far smaller than the claim.

• The claim "there's a mass shooting 9 days out of 10" is different from "there's an average 9 mass shootings per 10 days". The former is false, the latter is true. Commented Aug 23, 2018 at 14:54
• @Gerrit Sure, but the distinction is completely pointless and a waste of virtual ink. Commented Aug 23, 2018 at 16:25

There are two community data powered websites that will give you the information you need.

http://www.gunviolencearchive.org/last-72-hours

https://www.massshootingtracker.org/

281 U.S. mass shootings in 2018

2220 mass shootings since 1/1/2013

1 day since last mass shooting

-massshootingtracker

The MassShootingTracker about page shows a clear policy bias. https://massshootingtracker.org/about . They also state they use different definitions, which is part of the problem that OP is trying to be skeptical about.

GVA has a dedicated methodology page. https://gunviolencearchive.org/methodology