Are soldiers returning from service in Iraq and Afghanistan committing murder at a higher rate than people in the rest of their age cohort? That sounds unlikely. Most soldiers are very self-disciplined, and in returning from war experience a huge decline in stress. On the other hand, post-traumatic stress disorder is a serious problem for some returning vets.

The Jan. 14 The New York Times, in “Across America, Deadly Echoes of Foreign Battles,” says it found 121 cases in six years since 2001 of homicide by returned soldiers. This, said The Times, represented an 89-percent increase in the homicide rate among soldiers over the six previous years. But despite its length — mostly a recounting of the most lurid cases — the Times story didn’t reveal much about its methodology or put its figures into broader context.

If you do the math to compare the murder rate of these returnees with that in the same age cohort of the general population, you might see the soldiers faring better. One such calculation, by Ralph Peters, of the New York Post, found that war vets are about a fifth as likely to commit homicide as others from the wider cohort of young adults. That figure seems absurdly low — soldiers home from combat cannot really be that pacific compared with the average civilian. Or can they? Indeed, many soldiers return with a healthier respect for the tragedy of lethal violence.

That only hints at the difficulty of assessing how often combat overseas triggers homicide at home. It does in some cases, in others it does not — and in others, probably most, the truth may be impossible to know. The facts dug up by The Times remain far too sketchy to base a firm opinion on.