When the world looks at the United States, it sees a land of exceptions: a time-tested if noisy democracy, a crusader in foreign policy, an exporter of beloved music and film. But there is one quirk that consistently puzzles America's fans and critics alike. Why, they ask, does it experience so many mass shootings?
Perhaps, some speculate, it is because American society is unusually violent. Or its racial divisions have frayed the bonds of society. Or its citizens lack proper mental care under a health care system that draws frequent derision abroad. These explanations share one thing in common: Though seemingly sensible, all have been debunked by research on shootings elsewhere in the world. Instead, an ever-growing body of research consistently reaches the same conclusion. The only variable that can explain the high rate of mass shootings in America is its astronomical number of guns.
WHAT EXPLAINS MASS SHOOTINGS. The top-line numbers suggest a correlation that, on further investigation, grows only clearer. Americans make up about 4.4 percent of the global population but own 42 percent of the world's guns. From 1966 to 2012, 31 percent of the gunmen in mass shootings worldwide were American, according to a 2015 study by Adam Lankford, a professor at the University of Alabama. Adjusted for population, only Yemen has a higher rate of mass shootings among countries with more than 10 million people — a distinction Lankford urged to avoid outliers. Yemen has the world's second-highest rate of gun ownership after the United States.
Worldwide, Lankford found, a country's rate of gun ownership correlated with the odds it would experience a mass shooting. This relationship held even when he excluded the United States, indicating that it could not be explained by some other factor particular to his home country. And it held when he controlled for homicide rates, suggesting that mass shootings were better explained by a society's access to guns than by its baseline level of violence.
WHAT DOESN'T: CRIME, RACE OR MENTAL HEALTH. If mental health made the difference, then data would show that Americans have more mental health problems than do people in other countries with fewer mass shootings. But the mental health care spending rate in the United States, the number of mental health professionals per capita and the rate of severe mental disorders are all in line with those of other wealthy countries. A 2015 study estimated that only 4 percent of U.S. gun deaths could be attributed to mental health issues. And Lankford, in an email, said countries with high suicide rates tended to have low rates of mass shootings — the opposite of what you would expect if mental health problems correlated with mass shootings.
Racial diversity or other factors associated with social cohesion also show little correlation with gun deaths. Among European countries, there is little association between immigration or other diversity metrics and the rates of gun murders or mass shootings.
A VIOLENT COUNTRY. America's gun homicide rate was 33 per million people in 2009, far exceeding the average among developed countries. In Canada and Britain, it was 5 per million and 0.7 per million, respectively, which also corresponds with differences in gun ownership. Americans sometimes see this as an expression of deeper problems with crime, a notion ingrained, in part, by a series of films portraying urban gang violence in the early 1990s. But the United States is not actually more prone to crime than other developed countries, according to a landmark 1999 study by Franklin E. Zimring and Gordon Hawkins of the University of California, Berkeley. Rather, they found, in data that has since been repeatedly confirmed, that U.S. crime is simply more lethal. They concluded that the discrepancy, like so many other anomalies of U.S. violence, came down to guns.
MASS SHOOTINGS HAPPEN EVERYWHERE. Skeptics of gun control sometimes point to a 2016 study. From 2000 and 2014, it found, the U.S. death rate by mass shooting was 1.5 per one million people. The rate was 1.7 in Switzerland and 3.4 in Finland, suggesting U.S. mass shootings were not actually so common. But the same study found that the United States had 133 mass shootings. Finland had only two, which killed 18 people, and Switzerland had one, which killed 14. In short, isolated incidents. So while mass shootings can happen anywhere, they are only a matter of routine in the United States. Any individual can snap or become entranced by a violent ideology. What is different is the likelihood that this will lead to mass murder.
BEYOND THE STATISTICS. The United States also has some of the world's weakest controls over who may buy a gun and what sorts of guns may be owned. The United States is one of only three countries, along with Mexico and Guatemala, that begin with the opposite assumption: that people have an inherent right to own guns. The main reason U.S. regulation of gun ownership is so weak may be the fact that the trade-offs are simply given a different weight in the United States than they are anywhere else.
© 2017 New York Times
Americans make up about 4.4 percent of the global population but own 42 percent of the world's guns.
The United States has 270 million guns and had 90 mass shooters between 1966 and 2012.
No other country has more than 46 million guns or 18 mass shooters.