Mark Follman

There is no official or perfect way to measure mass shootings because the criteria varies and there is no perfect criteria. How many people do you need to get shot to have a mass shooting? There's some subjective choices that have been made in the criteria. When I first started studying this, intensively in 2012.

I created really what was the first online public database of mass shootings at Mother Jones. Nothing like that existed in 2012. It's part of the reason why I did it. We had to figure out what is the criteria for this? What are we going to include? I ended up taking what was a very conservative approach to defining the problem because I

I created really what was the first online public database of mass shootings at Mother Jones. Nothing like that existed in 2012. It's part of the reason why I did it. We had to figure out what is the criteria for this? What are we going to include? I ended up taking what was a very conservative approach to defining the problem because I

I created really what was the first online public database of mass shootings at Mother Jones. Nothing like that existed in 2012. It's part of the reason why I did it. We had to figure out what is the criteria for this? What are we going to include? I ended up taking what was a very conservative approach to defining the problem because I

That was the year of the movie theater massacre in Aurora, Colorado. That's what really set me off on this path in the first place. And then there were several more attacks that fall, and then Sandy Hook happened in December 2012. So I was gathering this data because it didn't exist publicly and had to find what the data was.

That was the year of the movie theater massacre in Aurora, Colorado. That's what really set me off on this path in the first place. And then there were several more attacks that fall, and then Sandy Hook happened in December 2012. So I was gathering this data because it didn't exist publicly and had to find what the data was.

That was the year of the movie theater massacre in Aurora, Colorado. That's what really set me off on this path in the first place. And then there were several more attacks that fall, and then Sandy Hook happened in December 2012. So I was gathering this data because it didn't exist publicly and had to find what the data was.

I was going with what criminologists who studied the problem had used and the FBI had used in more serial killer-related research. And it was like four or more people killed. Why is it four people instead of five or three? But that's what the professionals were using. So we went with that.

I was going with what criminologists who studied the problem had used and the FBI had used in more serial killer-related research. And it was like four or more people killed. Why is it four people instead of five or three? But that's what the professionals were using. So we went with that.

I was going with what criminologists who studied the problem had used and the FBI had used in more serial killer-related research. And it was like four or more people killed. Why is it four people instead of five or three? But that's what the professionals were using. So we went with that.

And then also, I was ruling out cases of armed robbery or gang wars or things happening in people's private homes because... What I was interested in understanding better was what is this thing that just happened in the movie theater? This is crazy. Is this happening more?

And then also, I was ruling out cases of armed robbery or gang wars or things happening in people's private homes because... What I was interested in understanding better was what is this thing that just happened in the movie theater? This is crazy. Is this happening more?

And then also, I was ruling out cases of armed robbery or gang wars or things happening in people's private homes because... What I was interested in understanding better was what is this thing that just happened in the movie theater? This is crazy. Is this happening more?

It was a year after the mass shooting in Arizona where then Congresswoman Gabrielle Giffords was shot and a bunch of other people were shot and killed. It felt as someone who had studied and reported on gun violence for several years, something's shifting here. So I went looking for data on mass shootings and I couldn't really find any, which blew my mind because this was not a new problem.

It was a year after the mass shooting in Arizona where then Congresswoman Gabrielle Giffords was shot and a bunch of other people were shot and killed. It felt as someone who had studied and reported on gun violence for several years, something's shifting here. So I went looking for data on mass shootings and I couldn't really find any, which blew my mind because this was not a new problem.

It was a year after the mass shooting in Arizona where then Congresswoman Gabrielle Giffords was shot and a bunch of other people were shot and killed. It felt as someone who had studied and reported on gun violence for several years, something's shifting here. So I went looking for data on mass shootings and I couldn't really find any, which blew my mind because this was not a new problem.

It goes back to Columbine and even before. It's a definitional problem, too, to try to say how many mass shootings are there. After we did that database, a bunch of other groups and media started collecting data. Now we're accustomed to these headlines that say, oh, there's been 782 mass shootings this year. But that's a broader way of measuring the problem.

It goes back to Columbine and even before. It's a definitional problem, too, to try to say how many mass shootings are there. After we did that database, a bunch of other groups and media started collecting data. Now we're accustomed to these headlines that say, oh, there's been 782 mass shootings this year. But that's a broader way of measuring the problem.

It goes back to Columbine and even before. It's a definitional problem, too, to try to say how many mass shootings are there. After we did that database, a bunch of other groups and media started collecting data. Now we're accustomed to these headlines that say, oh, there's been 782 mass shootings this year. But that's a broader way of measuring the problem.

They're using a broader criteria than we did back then, which was using a handful of cases that fit a more specific set of... Because of that range of criteria, it's very hard to say like, what is the probability? But I think the overall picture, it is a low probability event. There are not mass shootings happening every day in cities across America.