There have never been any school shootings in the US.

They have been over 100,000 gun violence incidents since Sandy Hook of which between 7 and 74 were at or near schools.

But, from what I understand, for a "school shooting" to occur:

1. The shooter needs to be a student
2. The shooting needs to be within the school
3. The shooter intended to kill students in the school
4. The shooting needs to happen during school hours
5. The shooting cannot be related to extracurricular reasons

Wow, that knocks out a lot of shootings.

In fact, using this criteria we can not only knock off a few victims from the toll, such as Rachel Scott who was shot outside the school at Columbine. We can also get rid of a few school shootings!

For example, the 1999 Jonesboro, Arkansas shootings occured OUTSIDE the school!

Even better, Adam Lanza WASN'T A STUDENT!  Even better, we can knock out a few of the victims are not students. This criteria confirms what gun nuts have been saying all along--The Sandy Hooks shootings weren't school shootings, but it was a mass shooting.

Now, if people want to look like dicks, then they have to admit this is the case and they can knock that one off the books.

The real confusion is whether a school shooting is a mass shooting or not.

Some people only want the mass shootings which happen in schools to be considered "school shootings".  That is the fallacy which Politifact falls into in their piece:

For many people, this is the first thing that comes to mind when they hear the phrase "school shooting" -- an incident such as Sandy Hook or, before it, the 1999 Columbine shooting in Colorado that left 15 dead, including the shooters.

But, the people who want to dispute these numbers want to limit the amount of School Shootings to a number which is somehow "acceptable" rather than address the issue that gun violence is far too pervasive in US culture.

On the other hand, The Daily Beast came up with the number 68:

We keep a tally of school shootings at The Daily Beast, too, using a slightly different methodology. We include only shootings that occur on school campuses while students are present. We count shootings that result in no fatalities as well as those where the only victim was a shooter who committed suicide.

We published a report last year using our data to show just what a school shooting looks like, noting specifically: “These events aren’t necessarily the types of tragedies that come to mind when one thinks of “school shootings”—madmen in fatigues roaming school hallways, strapped with automatic-style guns, murdering indiscriminately—nor do they receive the media attention of such mass shootings. But they can be similarly traumatizing for students and staff, and they have led to at least 24 injuries and 17 deaths over the past year.”

The following day, another school shooting at Arapahoe High School added to our tally. As of today, we count 68 school shootings, with 28 dead, and 66 injured.

Oliver Burkeman gets to the point in his post at the Guardian:

(If you think this kind of absurdity is confined to the fringe, see this only slightly less mendacious CNN piece (and Politifact), which brings the figure down from 74 to 15 by excluding, among others, shootings motivated by "personal arguments, accidents [or] alleged gang activities and drug deals". Johnson says the cable channel stole his work.)

What’s especially dispiriting about this flat denial of reality is how little prospect it offers for rational discussion or compromise. Even if you're a supporter of gun control, you can still hold a reasoned discussion with somebody who believes that the benefits of widespread firearms ownership outweigh the harms. You can discuss international comparisons; and how no comparable country experiences anything like this level of gun violence; the other person can seek to establish why those comparisons aren't relevant; or that, yes, violent deaths are actually in decline in the US, and so on. But when the pro-gun side of the argument consists of simply insisting that the gun violence that people are so distraught about isn't real gun violence? Then there's no clear way forward at all.

And let’s not forget the bigger point here. A pro-gun journalist applies the most stringent imaginable criteria to the term 'school shooting'; he rejects every instance he possibly can, for reasons many might regard as spurious, and then triumphantly declares that there have only been … seven bona fide school shootings in America since December 2012!

Only seven school shootings since December 2012.

I hope I never to get to the point at which the word "only" in that sentence makes even the slightest bit of sense.

As I said we can knock the numbers down even further if we want to say there have never been any school shootings in the US.  That should appeal to the people who do nothing to stop the plague of US gun violence.

So, do we want to split hairs or try to come up with a solution to a real problem is the real issue here.What is important is that people died. What category some people choose to put a specific shooting is irrelevant to our mission. Our mission is to stop future shooting, no matter what the location or circumstance.