Knee-jerk calls for gun control following Wednesday’s school shooting in Florida would not be effective, and they ignore measures that would, crime researcher John Lott said Thursday on “The Laura Ingraham Show.”

Lott (shown above), author of “More Guns, Less Crime,” pointed to the common thread connecting almost every recent mass public shooting in the United States — a setting that banned citizens from carrying guns. He said 98 percent of the mass public shootings since 1950 — including the shooting that killed at least 17 people at Marjory Stoneman Douglas High School in Parkland, Florida — have occurred in such places.

“We have yet another mass public shooting where guns are banned, in these ‘gun-free zones,’ where law-abiding citizens, general citizens, aren’t allowed to have guns to protect themselves,” he said.

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Lott said the same is true — and even more so — in gun-friendly Florida, where citizens are allowed to carry concealed firearms in most places.

So where have the mass shootings taken place?

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“Each and every one of them occurred in some of the very few places in Florida where guns are banned,” he said.

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In case some people might think that is a coincidence, Lott said he’s read the statements of many mass murderers who explicitly cited those policies as a reason they chose the location.

Even professional security guards are no substitute for armed citizens, Lott said.

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“What people don’t seem to appreciate is the extremely difficult job [of] having somebody in uniform with a gun,” he said. “I mean, it would be nice if it was easy. But the thing is, putting somebody in uniform there makes them a sitting duck. I mean, it’s like a neon sign above the person saying, “Shoot me first.'”

Critics of conceal-carry laws often raise the specter of accidental shootings — a citizen inadvertently shooting a bystander while trying to stop an attack or a police officer unwittingly shooting an innocent armed citizen.

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Lott acknowledged those are theoretical concerns. But while there are dozens of examples of armed citizens thwarting mass shootings, there are no examples of innocent people dying during the exchanges, he said.

“If you can’t even point to one case with the types of problems that they worry about have happened, it seems like we shouldn’t put undue weight on those types of things,” he said.

“There’s not one mass shooting during the whole century so far they can point to that would have been stopped if that law had already been in effect.”

In contrast, Lott said, the types of gun restrictions politicians inevitably propose following these tragedies would have been useless against mass shooters. One popular idea is extending mandatory background checks to private sales.

“There’s not one mass shooting during the whole century so far they can point to that would have been stopped if that law had already been in effect,” he said.

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The same goes for calls to ban guns from people on the federal government’s terror watch list. That would not have stopped Wednesday’s shooting or others, Lott said.

Lott said law enforcement authorities certainly could do a better job of identifying potential threats and intervening to stop mass killers before they act. But he said the best efforts inevitably would fall short.

“We can always hope that we can go and catch these guys beforehand, and we can try to improve those types of things,” he said. “My concern, though, is that you’re never going to be able to depend upon that … You have to have some backup plan. And the backup plan is to allow individuals to be able to go and defend themselves.”

PoliZette senior writer Brendan Kirby can be reached at [email protected]. Follow him on Twitter.