Even academics studying firearms, normally allowed to research their subjects above the political fray, their non-partisan motives given the benefit of the doubt, have become embroiled in the most contentious topic in American culture.

The NRA has called out Harvard University for “snake oil research” and warned its members about the “unscrupulous propagandists grasping at any opportunity to make a case for their preordained agenda” in their “fact sheets.”

But when it comes to the large and complicated question of whether people with guns are actually safer because of that ownership, the research supports the notion that proximity to a lethal weapon creates a greater likelihood of bodily harm and death.

Now, a new meta-analysis of gun research—the first systematic review of its kind—from the University of California, San Francisco, published in Annals of Internal Medicine today, has seemingly put an end to the debate over safety, at least in terms of suicide and homicide. Pooling results from 15 investigations, researchers found that a person with access to a gun is unequivocally less safe in terms of intentional death. Those with the ability to get to a gun are three times as likely to commit suicide and twice as likely to be the victim of a homicide than people without access.

Previous studies that include population level estimates have pegged the risks as even higher.

Guns are the most popular and effective method of killing—both of oneself and of others. Around 31,000 die by the gun annually and gun deaths make up over half of all completed suicides and over two-thirds of all homicides.

The study found that access to guns had a different effect on men and women. Men were nearly four times more likely to commit suicide than when firearms were not accessible, while women were almost three times more likely to be victims of homicide. And while men make up over three quarters of suicides and homicides overall, women with firearm access are more than twice as likely to be a victim of homicide than a man with gun access, mainly because of the increased threat of domestic violence.

There are a few striking things about this meta-analysis, the first of which is the extreme consensus across the entire body of literature amid reports from agenda-driven groups that often conflict about the safety of keeping firearms in the home.

Dr. Andrew Anglemyer, one of the study’s authors and a U.S. Army veteran, explains that in epidemiology research where all of the available evidence on a subject is synthesized to answer a particular question, the vast majority of the time, the examined research often comes to ambiguous, sometimes contradictory conclusions. What’s unique about this question of gun safety, he says, is that “when I reviewed all of the body of evidence, there isn’t any inconsistency. You at least expect some inconsistency, or contradictory evidence, but that’s not what I see here. We identified 15 studies, and 14 were significantly higher odds of suicide or being a victim of homicide. The only one that didn’t find a significant effect still trended toward a strong effect, it just wasn’t strong enough and was done in New Zealand, which has a proportion of gun owners two-thirds lower than the United States.”

In other words, “there’s not a lot of ambiguity about the risk of being a victim of homicide or suicide and being exposed to a gun or not,” he says.

Gun rights advocates have carefully crafted their defense of guns in these intentional deaths. They basically go like this: People “have to deal with their problems, not with the group of tools that they have,” and “If you don't have a gun, you'll use something else…there are a million ways to commit suicide." Both quotes come from former NRA President David Keene during a confrontation with a veteran and employee of Media Matters in 2012.

In what may be another blow to this logic, the UCSF study notes that most of the research controlled for mental illness and found that the increased risk of suicide and homicide remained, supporting the well-documented theory of impulsivity as the driving force in these deaths, not mental illness. A 2001 study from the University of Texas-Houston found that a quarter of survivors of near-lethal suicide attempts had contemplated killing themselves for less than five minutes before acting. For half, it was less than 20 minutes. Anglemyer explains, “a person is very depressed and they come home and there’s a gun readily available and they make a really bad decision…or there’s a bad argument and there happens to be a gun in the house and another bad decision is made.”

And yet, despite the risks, the number of firearm background checks reached a record high last year, and gun manufacturers continue to report booming sales. A majority of these gun owners say they arm themselves for personal safety, but the question lies in the definition of safe. Whether a gun in the home actually decreases the risk of harm from feared crimes is unclear, though Anglemyer calls it “a logical research question.” What can no longer be argued is that a firearm puts the owner and everyone else in the home at risk.