After a deadly shooting, the debate always, it seems, breaks down like this: One side argues for gun control, and the other argues there is no research proving those measures work. There is, in fact, little research into gun violence at all—especially compared to other causes of death in the United States.

The modern origins of the impasse can be traced to 1996, when Congress passed an amendment to a spending bill that forbade the Centers for Disease Control and Prevention from using money to “advocate or promote gun control.”

https://www.theatlantic.com/health/archive/2018/02/gun-violence-public-health/553430/