This comment was inspired by a map that's been making it around social media which purports to show "the 74 school shootings since Sandy Hook". The map is based on a running list compiled from news reports by Everytown for Gun Saftey, a Michael Bloomberg affiliated "grassroots" advocacy group for gun control.
The interesting thing about these kinds of data manufacturing efforts by advocacy groups is that at times when there is no other "data" available about some topic which catches the public imagination, such informal efforts at statistics can catch on with media venues and become received wisdom. And yet, the criteria for putting together such a list is often highly influenced by the fact it's an advocacy organization doing the compilation work. In the case of the "74 school shootings" list, the criteria listed are:
Incidents were classified as school shootings when a firearm was discharged inside a school building or on school or campus grounds, as documented in publicly reported news accounts. This includes assaults, homicides, suicides, and accidental shootings.... Incidents were identified through media reports, so this is likely an undercount of the true total.Part of what makes this kind of advocacy work is that people have an idea of a "school shooting" is: Some disaffected student decides to go out in a blaze of media glory and blazing guns, or else some insane adult decides to go to a school and slaughter as many innocents as possible before turning his gun on himself. There are a few famous incidents (Columbine, Sandy Hook) which fit this model very nicely, and the "74 school shootings" claim gives the idea that there are many other similar incidents which just haven't received as much news coverage.
However, when someone goes through the list of school shootings and starts to look up the news stories, a much wider range of events starts to emerge.
For instance, #10 on the Everytown list is a shooting at Hillside Elementary in San Leandro, CA. The actual news report says:
Investigators in the East Bay say they have leads, but no suspects, yet in the murder of a 19-year-old Laney College student. Travion Foster was shot and killed just before 9 p.m. Wednesday in the field behind Hillside Elementary School.... Foster was shot and killed Wednesday night in the field behind San Leandro's Hillside School. The Alameda County Sheriff's Department say it appears Foster was involved in a game of dice with several others, when gunfire erupted.
#9 is a shooting at Indian River State College in Florida, which resulted from police chasing a man brandishing a gun in a pickup truck around town until cornering him in a parking structure on the college campus, where a shootout ensued which injured a college-student bystander before the suspect was successfully arrested. The news story reports that police chief Sean Balwin "said he believes the man ending up at the college was just a coincidence."
Gun control advocates could certainly point to these as incidents showing that guns do show up in crimes frequently in the US, but they certainly don't fit the profile of "school shooting" which exists in the public's imagination. And yet the argument that more needs to be done to reduce gun crime in general is somewhat problematic for gun control advocates because gun crime has reduced by around 50% over the last thirty years, even while gun laws have generally been relaxed and gun ownership has risen. Thus, it becomes necessary to produce a "trend" towards some specific kind of gun crime which demands legislative action. And so we have this effort to produce "data" by collecting news reports around a term which everyone thinks they know the definition of, but using a set of criteria which does not match that definition.
The effort also takes advantage of people's inability to think very well about unlikely events. "Almost one school shooting per week!" is the claim being made based on this somewhat inflated "data". Allow the count for a moment and consider what the denominator to that numerator is. There are around 125,000 schools in the US and around 4,000 colleges. If there are 52 "school shootings" per year, that means there is a 0.04% chance of any given school experiencing a shooting any given year. In other words, the average educational institution can expect to experience one shooting every 2,480 years. And that's only if we count events like murders over late night dice games in the field next door as "school shootings". A tighter filter could easily push that number out to a school shooting every 5,000 to 10,000 years. Please check your laser pistols and flint axes at the door, children.