Gun control really works — here's the science to prove it

• After last week's mass shooting at a Florida high school, many in the US are wondering what sort of gun-control measures could prevent more gun violence.
• Despite some restrictions on gun research, scientists have sought to evaluate whether specific policies effectively reduce gun deaths.
• Policies that seem to reduce rates of gun violence include stricter background checks, limiting access to dangerous weapons, and prohibiting domestic abusers from owning weapons.

There are close to as many guns in the US as there are people. There may be more, or there may be fewer, depending on which study you look at — there's no exact count, since there isn't a national database of gun purchases or firearm owners, and federal law does not require a prospective gun owner to get a license or permit.

That's one of the many obstacles researchers come up against when trying to evaluate why so many people die from guns in the US.

But as the country tries to figure what — if anything — can be done in the wake of yet last week's mass shooting at Marjory Stoneman Douglas High School in Florida, it's worth taking a look at the evidence we have on the effects of gun regulations.

Despite some congressional limitations on gun research, scientists have sought to evaluate the effects of gun-control legislation in the US and in other places around the world.

Here's what the data shows.

SEE ALSO: A spike in gun sales after the Sandy Hook massacre led to a tragic increase in accidental deaths — especially among kids

Making it easier to carry concealed guns increases the number of gun homicides.

States that have so-called right-to-carry laws require them to issue concealed-carry permits to anyone who is allowed to own guns and meets the necessary conditions.

Many people have argued that right-to-carry laws deter crime because there would be more armed people around to stop a shooter. Though that idea was supported by a controversial 1997 analysis, recent and more thorough analyses have found the opposite effect.

One recent study found that such laws increased the rate of firearm homicides by 9% when homicide rates were compared state-by-state. That could be because confrontations were more likely to escalate to a shooting, or because there were more guns around that could be stolen, or some other factor.

A spike in gun purchases after the 2012 shooting at Sandy Hook Elementary School led to an increase in accidental gun deaths, especially among kids.

Research has found that when people are around more guns, they're more likely to end up dying from accidental shootings.

After a 20-year-old man killed 20 children and six adults at Sandy Hook Elementary School in Newtown, Connecticut, in December 2012, calls for legislation aimed at limiting access to firearms resulted in what's now become a predictable phenomenon after shootings: people bought lots of guns.

With more guns around in the following months, the rate of accidental deaths related to firearms rose sharply, especially among children, a recent study published in the journal Science found.

According to the researchers' calculations, 40 adults and 20 children died as a result of those gun purchases.

Barring people convicted of domestic abuse from owning guns has a huge effect on the number of gun deaths.

The so-called Lautenberg amendment to the 1968 Gun Control Act disqualifies people with a misdemeanor conviction for domestic violence from buying or owning weapons.

Researchers found that gun murders of female intimate partners decreased by 17% as a result of the amendment.