When the world looks to the United States, it sees a land of exceptions: a tried but noisy democracy, a crusader in foreign policy, an exporter of beloved music and movies.
But there is one quirk that constantly intrigues American fans and critics. Why, they ask, does he experience so many mass shootings?
Some may speculate that it is because American society is exceptionally violent. Or its racial divisions have frayed the bonds of society. Or its citizens lack proper mental care under a health care system that is often derided abroad.
These explanations share one thing in common: while seemingly sensible, all have been debunked by research into shootings elsewhere in the world. Instead, an ever-increasing body of research consistently comes to the same conclusion.
The only variable that can explain America’s high rate of mass shootings is its astronomical number of guns.
A look at the numbers
Early numbers suggest a correlation that, upon further investigation, only becomes clearer.
Americans make up about 4.4% of the world’s population, but own 42% of the world’s firearms. From 1966 to 2012, 31% of gunmen in mass shootings around the world were Americans, according to a 2015 study by University of Alabama professor Adam Lankford.
Adjusted for population, only Yemen has a higher rate of mass shootings among countries with more than 10 million people – a distinction Mr Lankford urged to avoid outliers. Yemen has the second highest gun ownership rate in the world after the United States.
Around the world, Lankford found, a country’s gun ownership rate correlated with its chances of experiencing a mass shooting. This relationship held even when he excluded the United States, indicating that it could not be explained by any other factor particular to his country of origin. And that held when he controlled for homicide rates, suggesting that mass shootings were better explained by a society’s access to firearms than by its baseline level of violence.
Factors that are not correlated
If mental health made a difference, then the data would show that Americans have more mental health issues than people in other countries with fewer mass shootings. But the rate of spending on mental health care in the United States, the number of mental health professionals per capita and the rate of serious mental disorders are all in line with those of other wealthy countries.
A 2015 study estimated that only 4% of gun deaths in the United States could be attributed to mental health issues. And Mr 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 issues were correlated to mass shootings.
The fact that a population more or less plays video games also seems to have no impact. Americans are no more likely to play video games than people in any other developed country.
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 rates of firearm killings or mass shootings.
A violent country
The rate of firearm homicides in the United States was 33 per million population in 2009, far exceeding the average for developed countries. In Canada and Britain, it was 5 per million and 0.7 per million, respectively, also reflecting differences in gun ownership.
Americans sometimes see it as an expression of deeper problems with crime, a notion rooted, in part, in a series of films depicting urban gang violence in the early 1990s. But the United States is not really more crime-prone than other developed countries, according to a landmark 1999 study by Franklin E. Zimring and Gordon Hawkins of the University of California, Berkeley.
On the contrary, they found, in data that has since been repeatedly confirmed, that American crime is simply deadlier. A New Yorker is just as likely to be robbed as a Londoner, for example, but the New Yorker is 54 times more likely to be killed in the process.
They concluded that the gap, like so many other anomalies of American violence, boiled down to guns.
More gun ownership corresponds to more gun murders in virtually every axis: among developed countries, among US states, among US cities, and controlling crime rates. And gun control laws tend to reduce gun murders, according to a recent analysis of 130 studies from 10 countries.
This suggests that the weapons themselves are the source of the violence.
Comparisons in other companies
Gun control skeptics sometimes point to a 2016 study. From 2000 to 2014, it found that the death rate from mass shootings in the United States was 1.5 per million people. The rate was 1.7 in Switzerland and 3.4 in Finland, suggesting that mass shootings in the United States were not that common.
But the same study found that the United States had 133 mass shootings. Finland only had two, which killed 18, and Switzerland had one, which killed 14. In short, isolated incidents. So while mass shootings can happen anywhere, they are just a matter of routine in the United States.
As with any crime, the underlying risk is impossible to completely erase. Any individual can fall for or be fascinated by a violent ideology. What’s different is the likelihood of it leading to mass murder.
In China, about a dozen seemingly random attacks on schoolchildren killed 25 people between 2010 and 2012. Most used knives; none used a firearm.
By contrast, in that same window, the United States experienced five of its deadliest mass shootings, which killed 78 people. On a population scale, US attacks were 12 times more deadly.
In 2013, American firearm-related deaths included 21,175 suicides, 11,208 homicides, and 505 accidental discharge deaths. That same year in Japan, a country with a third of the American population, firearms were implicated in only 13 deaths.
This means that an American is about 300 times more likely to die by homicide or firearm accident than a Japanese. The gun ownership rate in the United States is 150 times higher than that of Japan. This gap between 150 and 300 shows that gun ownership statistics alone do not explain what makes America different.
The United States also has some of the weakest controls over who can buy a gun and what types of guns can be owned.
Switzerland has the second highest gun ownership rate of any developed country, about half that of the United States. Its firearm homicide rate in 2004 was 7.7 per million population – an unusually high rate, consistent with the relationship between gun ownership and murder, but still a fraction of the rate. in the USA.
Swiss firearms laws are stricter, setting a higher bar for obtaining and maintaining a license, for selling firearms, and for the types of weapons that can be owned. These laws reflect more than stricter restrictions. They imply a different way of thinking about firearms, as something citizens must affirmatively earn the right to own.
The difference is the culture
The United States is one of only three countries, along with Mexico and Guatemala, that makes the opposite assumption: that people have an inherent right to own guns.
Perhaps the main reason that US gun ownership regulations are so weak is because trade-offs simply carry a different weight in the US than anywhere else.
After Britain had a mass shooting in 1987, the country instituted strict gun control laws. So did Australia after a shooting in 1996. But the United States has repeatedly faced the same reckoning and determined that relatively unregulated gun ownership is worth the cost to society.
This choice, more than any statistics or regulations, is what most distinguishes the United States.
“In retrospect, Sandy Hook marked the end of the American debate on gun control,” wrote Dan Hodges, a British journalist, in a post on Twitter two years ago, referring to the 2012 attack that killed 20 young students at a Connecticut elementary school. “Once America decided that killing children was bearable, it was over.”