There are a lot of things we think we know about mass shootings: that they come about when mentally unstable individuals suddenly snap; that there are more and more of them every year; that smarter and stricter laws can help prevent them. A new article in the journal Homicide Studies says that all of those assumptions are wrong.

In the article, titled “Mass Shootings in America: Moving Beyond Newtown,” Northeastern University criminologists James Alan Fox and Monica J. DeLateur examine existing research and data to refute 11 common assumptions about mass murder—which the FBI defines as any single, sustained incident that takes the lives of four or more victims. Many of their points seem like the starting point for a conversation rather than the end of one. But if we’re going to have a national conversation about mass shootings—and we’re already having it—then it might as well be based on data rather than assumptions.

The biggest myth they claim to bust? The idea that mass murder in America is on the rise. Fox and DeLateur specifically challenge a recent Mother Jones project that claimed “a recent surge in incidents and fatalities” from mass shootings. The authors argue that Mother Jones arbitrarily limited its analysis to certain types of mass shootings—ones occurring in public places, committed by lone gunmen with no robbery motive or gang affiliation—and that by limiting the data set the magazine came away with skewed results. By expanding their analysis to include all mass shootings regardless of location or motive, Fox and DeLateur found that the rate of mass shootings has remained steady from 1976 to 2011, at about 20 incidents per year, and that “the facts clearly say that there has been no increase in mass shootings and certainly no epidemic.” I read the Mother Jones piece when it appeared, and I found it tragic and convincing. But Fox and DeLateur also sound convincing when they argue that “including mass shootings in all forms can only add to our understanding of extreme killing.” At the very least, Fox and DeLateur’s findings add nuance to a topic that is often oversimplified.

The authors also dispute the notion that shoot-‘em-up video games and other forms of violent entertainment somehow encourage unstable individuals to commit mass murder, noting that “the ability to document a direct causal link indicating that consuming violent entertainment leads to violent behavior has eluded social science researchers for years.” I’ve written about this very topic multiple times for Slate, usually in reference to the notion that Sandy Hook shooter Adam Lanza’s fondness for violent video games was causally connected to his real-life crimes. I find this argument unsatisfying, and so do Fox and DeLateur, who write that Lanza’s “gaming may be more a symptom of his personality and temperament than the cause.”

And, perhaps most dispiriting, the authors argue that pretty much every policy proposal intended to reduce mass shootings has been worthless. Increased funding for and access to mental health treatment? A well-meaning idea, but likely ineffective in preventing mass murder, given that, “with their tendency to externalize blame and consider themselves as victims of mistreatment, mass murderers see the problem to reside in others, not themselves,” and thus would likely avoid all opportunities to receive psychiatric help. Would renewing the 1994 federal assault weapons ban do any good? Probably not: “a comparison of the incidence of mass shootings during the 10-year window when the assault weapon ban was in force against the time periods before implementation and after expiration shows that the legislation had virtually no effect, at least in terms of murder in an extreme form.”

What about implementing stricter security measures in schools and other public places? Actually, “most security measures serve only as a minor inconvenience for those who are determined to cause mayhem.” As an example, the authors cite a pair of Arkansas middle school students who pulled the fire alarm in their school and began shooting people as they came outside. What about expanding criminal background checks for firearms purchasers? “Most mass murderers do not have criminal records or a history of psychiatric hospitalization. They would not be disqualified from purchasing their weapons legally.”

What, then, can be done to stop mass shootings in America? Maybe nothing. “Eliminating the risk of mass murder would involve extreme steps that we are unable or unwilling to take—abolishing the Second Amendment, achieving full employment, restoring our sense of community, and rounding up anyone who looks or acts at all suspicious,” the authors conclude. “Mass murder just may be a price we must pay for living in a society where personal freedom is so highly valued.” Well. Merry Christmas, I guess.