## Turns out it?s higher than we?ve been willing to admit

Photo by hjl/flickr

Amidst the national conversation we seem to have about every third school shooting ? between the hot takes and the impassioned pleas for sanity one way or another ? there seems to be one familiar refrain. It?s something which in part soothes our gaping emotional wounds, and which in part reassures us that the status quo is acceptable. It goes something like this:

School shootings are tragic and upsetting, but they are (a) impossible to stop, even with common sense gun laws. But don?t worry, because (b) although these tragedies have been getting a lot of coverage, and while it does seem like it?s happening a lot more recently, they are still exceedingly rare, and even when they do occur, have relatively low casualty rates ? even if the trend continue to rise.

It seems like (a) isn?t really that much of an argument, because ?common sense gun laws? tend to be anemic and almost intentionally crafted to be ineffective. This weak argument, however, is reinforced by (b), which tells us that this really isn?t even that much of a problem ? that the odds of your child being gunned down in their school is so remote, that you might as well take your chances, because that is the price we pay to live in a free society.

Now, I?m not much of a policy expert, so I don?t think I have much to offer on (a), however I am somewhat equipped to address (b): what are the chances that your child?s school will be in a shooting at some point in their life?

## Spoiler alert, the answer is 1 in 63.

1 in 63 is slightly worse odds than getting a three of a kind in poker (1 in 46), though slightly better than winning $4 in the Powerball with a PB+1 (1 in 92). That is to say, these things are not only possible, but we sometimes take for granted that they eventually will happen.

Now, these odds may seem a bit high to you, and that?s probably because you?re probably used to seeing statistics being used to downplay the tragedy of school shootings by making the odds of them happening to you or your children seem remote. This is accomplished somewhat deceptively by citing annual risk of death from firearms violence in schools and comparing then to other mortality probabilities. From some idiot on Quora, partially quoting World Gun Ambassador Ted Nugent:

You have a 0.0012% chance of dying in a mass shooting based on numbers from the CDC?.An average of 27 people die in mass shootings each year. Around 15,000 people die of murders each year. Around 38,000 people are killed in automobile accidents each year. A whopping 1,400 times more people die in cars than in mass shootings. 3500 teens are killed each year texting while driving.

Of course, it?s impossible to verify all these numbers, as we don?t know where they?re being pulled from or how they?re being calculated. For example, the automobile deaths number appears to be averaged from 2007, 2010, and 2011 insurance actuary tables for some reason; the numbers for texting while driving seems to be accurate for 2015, but only 216 of these deaths were actually teens; and a school shooting is a subset of mass shootings, so it?s not exactly applicable. So fuck it, let?s come up with some clean numbers.

An average of 17 people are killed every year in school shootings from the last 5 years. There are 50.76 million secondary to post-secondary school age children. That is about a 0.000033% chance, or 1 in 2.99 million of any given child being killed in any given year in a school shooting. Wow! You have better odds of getting PB+4 in the Powerball, but, uh, not the actual Powerball. So sorry.

## Of course, this does not show the whole picture.

We?re not only interested in the overall chance of death, but the chance that you?re going to get that phone call from the district, informing you that there has been a shooting at your child?s school. What are the chances that your child is hurled into a war zone, where safety is not guaranteed, and that their friends ? or their friends of friends ? are senselessly butchered before their eyes in the most familiar environment to them aside from home?

Yeah, shit, I guess I?m worried about that for some reason. Go figure.

In fact, I really only found myself seriously worrying about these kinds of things when I suddenly and quite happily became an expecting parent this year. Sure, I had always cared about the abstract policy and loved having academic discussions on the topic, but I never really had much skin in the game. But now I do, and now I?m asking the big goddamn questions, like what are the odds that my child?s school will be in a shooting?

To answer this question, I had to make a number of assumptions, but I will be citing my sources as much as possible, and will try to explain everything I?m doing as much as possible. I want to be as transparent as possible in my process to help you understand how we got at these odds and for my sake so I don?t get accused of pulling numbers out of my ass.

There have been 23 school shootings in 2018 as of May 20. The definition of a school shooting is somewhat contentious in certain circles, and I?m sure it will be even more contentious that I?m using CNN?s definition:

- At least one person is shot, not including the shooter.
- Occurs on school grounds.
- School being defined as any K-12 or post-secondary institution.
- Includes gang violence, fights, and domestic violence.
- Includes accidental discharge of a firearm, provided criteria 1 and 2 are met.

16 secondary schools (middle or high school level) were attacked this year, while 7 were post-secondary institutions (colleges or universities). There are 37,100 secondary schools in America, both public and private, and 6,551 post-secondary schools. Although there are half as many school shootings at post-secondary schools, there are five times as many secondary schools, meaning it?s actually more likely that a school shooting would take place at a college or university.

We can project that there will be 50.81 school shootings in 2018 using a linear regression model based on the number of shootings that have happened thus far as of May 20. This is calculated counting only days where school is in session, so we do not inflate our numbers by counting weekends or summer break. This of course doesn?t account for colleges where students are sometimes on campus year round, but it is a concession I?m willing to make.

We?re also going to make a big assumption here: that this rate holds for the foreseeable future. Some might argue that this is unrealistic, especially if this is an outlier year. Personally, I agree that this is unrealistic, because I see this number getting larger in years to come. Projecting out this far just using 18 data points is probably kind of silly, but the point I would like to make here is that there is a trend, and it?s not downward, so assuming this projection for the foreseeable future is, as I see it, a concession.

Presuming the current college/high school distribution holds, this means we will see 35.35 shootings at secondary schools, and 15.46 at post-secondary schools. Given the number of each institution, this means that for any given year, there is a 0.10% chance of any given high school or middle school being in a school shooting, or 1 in 1,050; and a 0.24% chance for any given college or university, or 1 in 424.

You may have noticed that we?re already orders of magnitude beyond those oft cited mortality statistics. But we?re not even done yet, because this is just for one year. We have to consider the entire educational career of the child.

Ideally, a child is going to attend secondary schools for grades 6?12, and college in four years. Of course, this is not always the case. Some kids get held back in high school, or skipped ahead. Not all students are enrolled in traditional programs. And the average college student actually takes 6.33 years to complete a bachelor?s degree. For the sake of simplicity however, let?s just say 11 years total ? 7 in secondary, 4 in post secondary. But since there are different probabilities of a school shooting at either type of institution, we have to calculate them separately ? 1 in 150 odds for a school shooting over 7 years in middle and high school, and 1 in 106 odds over 4 years in college.

Taken together, the odds of your child?s school being in a shooting in their lifetime is 1 in 62.51, or 1.6%. Woof.

This, of course, involves a lot of guesswork. Does one school have the same chance of an attack as any other? Can we really expect 50 school shootings by the end of the year? Will this really hold steady for the foreseeable future? Honestly, I don?t know. It has been mentioned to me that I was not taking into account any changes in gun laws down the line ? that society will finally have had enough and do something about this epidemic. And honestly, yeah, I didn?t. I assume it?s going to keep getting worse ? because that?s exactly what?s going to happen if we don?t do anything.

Hopefully, after finally realizing what the odds are, we finally will.