The issue focused on an online study that looked at what research did and did not show an increase in gun violence.

Giffords, the former Republican Arizona congresswoman, was shot in the head in an April 11, 2011, attack.

The study, which was released on March 20, found that about 4,000 people are shot in the U.S. every year, and that was on the high end.

The study was based on U.S. Department of Justice data