Mass shootings such as last week’s in Florida have prompted law enforcement and the media to look for patterns, and here’s one that has emerged: A disturbing number of perpetrators have previously been accused of domestic abuse.
Everytown for Gun Safety, a gun-control-advocacy group, analyzed FBI data on mass shootings from 2009 to 2016 and found that in 54 percent of cases, the victims included the shooter’s current or former spouse or intimate partner, or another family member - and 16 percent of attackers between 2009 and 2015 had previously been charged with domestic violence.
Not every perpetrator of domestic violence goes on to commit more serious crimes. But the link is just another way that society has underestimated the scale and effects of such abuse. That is why we are planning a major study to map out the size of the problem and discover the best policies to reduce it.
There is already a huge body of research showing the lasting effects of domestic violence on victims: Survivors are more likely than others to be affected by mental-health problems, as well as a host of chronic illnesses.The Centers for Disease Control and Prevention estimates that in the United States about 1 in 4 women and 1 in 7 men have experienced severe physical violence from a partner in their lifetimes. This includes being hit with a fist or a hard object, beaten or slammed against something.
Research for the Copenhagen Consensus Center by James Fearon of Stanford University and Anke Hoeffler of Oxford University estimates that, in one year, approximately 300 million women age 15 to 64 are assaulted by an intimate partner: That’s every ninth woman in the world, every year.
This is based on international surveys in which women are asked if they were assaulted in the past year. It is likely that these numbers underestimate reality. They show that in sub-Saharan Africa, 28 percent of women were assaulted in the past year.
At 4 percent, the figure is lower for rich countries, but it still indicates that more than 4 million women were assaulted in the United States in the past 12 months.
By comparison, terrorism claimed fewer than 1,000 lives in 2015 in Western countries and around 30,000 deaths globally that year. The total cost from conflict (deaths from wars and terrorism, refugee-related costs and economic damage) adds up to about 0.2 percent of global gross domestic product each year, according to Fearon and Hoeffler. Intimate-partner violence costs the world about 25 times more: around 5.2 percent of global GDP. For every battlefield death, nine people are killed by interpersonal violence. One child is murdered for every two combatants who die.
The costs to society are vast - and poorly understood. In a 2010 study, economists calculated that the average cost of a single sexual assault in the United States amounted to $240,776 - from the victim’s pain and suffering, medical bills, lost productivity, judicial system expenses and the lost productivity from the incarcerated offender.
One aggravated assault costs society about $107,020, with $95,023 from pain and suffering, plus the burden of increased risk of homicide.
On the basis of this lower figure alone, the total cost to the United States of the almost 5 million domestic violence cases per year is about $460 billion. In other words, if we could find a way to reduce these incidents by half, the benefits would be the same as making the country at least $230 billion better off every year. That’s nearly 10 times the entire annual Justice Department budget.
The global costs are also huge. Using the same methodology, Fearon and Hoeffler calculate that the annual cost of domestic violence internationally totals an astonishing $4.3 trillion. If we could cut that in half, the benefits would be 15 times the $142 billion the world spends annually on global aid programs.
Yet we know relatively little about how to halt abuse. Many behavioral campaigns rely on messages condemning violence. These may have helped to bring the issue to our attention, but promoting fear and shame does not appear to change the behavior of abusers.
Small-scale studies have shown promising signs in some areas: In Britain, bars whose staffs were trained to reduce the consumption of alcohol by already intoxicated customers was found to decrease violence by patrons by 10 percent, compared with bars without such training.
This policy was shown to have benefits worth 17 times the very low cost of implementation. In the state of Washington, an initiative in which social service and welfare officers made early responses to at-risk homes was found to have benefits to society of about 14 times the program’s costs.
But it is clear there is no silver bullet. That is why we are undertaking research to find out more - and ultimately to identify cost-effective solutions. Given the huge toll, domestic violence deserves much more of the world’s attention and resources.
Bjorn Lomborg is president of the Copenhagen Consensus Center. Michelle A. Williams is dean of the Harvard T.H. Chan School of Public Health.