This meant that about 7 percent of all children in the United States lived in a house in which at least one gun was stored in an unsafe manner. This was about twice the number reported in the previous national survey, published in 2002. Other research suggests that many people in gun-owning households, typically not the primary owner of the gun, think they are safely stored when they are not.

Critics of gun-storage laws say homeowners need to be able to act quickly if a criminal tries to enter a home. It’s not easy to measure how often guns are used in self-defense when someone attempts a break-in, but research suggests it’s a rare occurrence.

Suicides are less rare than self-defense shootings and, along with accidents, they are more likely in children who have parents who abuse alcohol. Studies have also found that children living with an adult who misuses alcohol were more likely to live in a house with a gun stored unsafely, and that heavy alcohol use was most common in those who store guns loaded and unlocked.

“We know from prior studies that children who live with alcohol-misusing adults are at a greater risk of suicide attempt, bullying victimization and perpetration, and unintentional injuries,” said Dr. Ali Rowhani-Rahbar, an associate professor of epidemiology at the University of Washington’s School of Public Health.

Critics also say safe storage laws are hard to enforce because of privacy concerns. As a model from Monday’s study in JAMA Pediatrics shows, though, even a modest intervention that motivates households to safely store guns could reduce youth firearm deaths by 6 percent to 32 percent.

Possible safety measures

Last year, in the journal Injury Prevention, Dr. Rowhani-Rahbar and other researchers reported on the results of two community-based firearm safety events in Washington State. They found that presenting people with information and offering to sell them trigger guards or lockboxes resulted in an increase of about 14 percent of households that stored all guns locked and 9 percent more that stored them unloaded.

In 2017, the Government Accountability Office reviewed 16 public or nonprofit programs that aimed to improve the storage of guns. It also reviewed studies of these programs. It found that distributing locks led to more safely stored guns. Few of these evaluations were rigorous, however. (Gun research, as with most things related to guns, is a politically divisive issue, and for many years research funding has been very low relative to other major causes of death.)