Barbara Howard: The shooting at Sandy Hook Elementary School in Newtown, Connecticut was five years ago today. In the aftermath, President Obama offered words of comfort to Newtown and to the nation.

SOUND CLIP FROM BARACK OBAMA:

In the hard days to come, that community needs us to be at our best as Americans, and I will do everything in my power as president to help.

Howard: But when President Obama pushed for new gun control policies in the wake of Sandy Hook, it triggered an uptick in gun sales. After the shooting in Newtown, three million guns were sold above and beyond what would have been typical for that time period. Sandy Hook cast new light on unintended consequences — inevitable talk about what to do about guns followed by a spike in gun sales.

A new study out in the journal "Science" goes even further. It links those additional gun sales after Sandy Hook to 60 additional accidental gun deaths, including 20 children. Coincidentally, that is the same number of children who were killed at Sandy Hook. One of the study's authors, Phillip Levine, is in the studio with me. Thanks for coming in.

Levine: I'm glad to be here.

Howard: Now how do you go about directly attributing those deaths to the upsurge in gun sales after Sandy Hook?

Levine: What we look at in the data is this very large spike in gun sales that took place immediately following Sandy Hook which, essentially, you could think of as a coincidence in terms of timing. And what we look for is right exactly at that time that that spike occurs in sales, do we also happen to see a spike in accidental deaths that occurs in exactly the same time period? And the answer is that we do. And we see a very large spike, something just all of a sudden shoots right up, and then a few months later, shoots right back down. And something else happens at exactly the same time — the accidental deaths shoot up exactly when the gun sales spike up, they shoot down exactly when the gun sales spike down. We also happen to see that in the states in which those spikes were the largest, we also see accidental firearm deaths increase the most in those states. That's just too much of a coincidence.

Howard: Which states were they that you saw that spike, the most pronounced?

Levine: Two of the states that had the biggest spikes were West Virginia and New Hampshire.

Howard: These deaths seem to have a larger impact on children, and why is that?

Levine: Because they're the ones who might be likely to pick up the gun and play with it if they're exposed to it.

Howard: Why would it be happening right after Sandy Hook more than any other time?

Levine: With the increase in gun sales that took place at that time, children may have greater exposure to the guns because the gun just came into the house, the kid happens to pick it up and then a tragic event results.

Howard: After these mass shootings, are there always cries for gun controls to be put in place?

Levine: Really, the only two mass shootings in which we do see very large spikes in gun sales, are after Sandy Hook and after San Bernardino. Those are the two in which actual policy proposals were put on the table that had a reasonable chance of success. So after Sandy Hook, President Obama spoke very forcefully about the need for gun control legislation, including actually introducing legislation that ended up not being successful — those laws never got enacted. And what's interesting about it, is you see significant spikes in the number of people who search on Google for terms like ‘Where do you buy a gun?' The day the president would give those speeches, you’d see these huge spikes.

You see similar evidence right after San Bernardino, after the terrorist attack that took place a couple of years later when President Obama introduced executive orders that were related to gun control. At that point, you see very large spikes in gun sales, as well. Other than that, you really do not see spikes in gun sales that occur immediately after mass shootings. For instance, after the Las Vegas shooting a couple of months ago, there was nothing there. And the reason why you don't see anything now is because nobody's really worried about gun control legislation being enacted.

Howard: Sounds like a terrible unintended consequence.

Levine: There's definitely issues of unintended consequences here. Certainly, the legislation that was being introduced at the time and President Obama's efforts to enact gun control legislation was done with goodwill, with an intent to reduce gun deaths. What we see in the study is actually the opposite outcome — that in this particular instance, we see accidental gun deaths rose as a result.

Howard: What can be done about this? I mean people, of course, are going to be asking for something to be done about guns after there's a mass shooting. So what, are people to stay silent?

Levine: You know, I think that the right way to think about this is that to the extent that gun control legislation is going to be successful, it has to be introduced, debated and passed. What ends up happening, if it just gets introduced and discussed, but not enacted, you're just going to get the costs associated with the discussion and not the potential benefits.

Howard: OK, thanks so much for coming in.

Levine: Thank you for having me.

Howard: That's Professor Phillip Levine. He is co-author of a study out in the journal "Science" that shows that the surge in gun sales after the Sandy Hook shooting caused an additional 60 accidental deaths above normal; 20 of those were kids. That happens to have been the same as the number of children who were killed at Sandy Hook Elementary School five years ago today.