In recent weeks, the firearms controversy has again lit up the media in the United States, with clarification that anyone engaged in the business of selling firearms must get a license and conduct background checks.

But, argues Fred Rivara from the Seattle Children’s Research Institute and Harborview Injury Prevention and Research Center, we may never know its effects because of the continuing ban on federal funding of research into gun violence.

http://www.bmj.com/content/352/bmj.i578