A survey  commissioned by the National Collegiate Athletic Association found that despite rules changes and legislation, the frequency of concussions among football players in all three divisions has remained steady in the past seven years. The survey, which relied on accurate reporting from athletics programs (concussions are notoriously difficult to diagnose, and there has been concern athletes might be reluctant to report one and risk sitting out), found that such head injuries occurred 2.5 times per 1,000 "game-related exposures." Each game or practice counts as one exposure, regardless of the length. That figure is down from 3.4 per 1,000 in 2004-5, but the NCAA said the year-to-year difference is not statistically significant.
The NCAA has put in place a number of safety regulations designed to deter concussions since then, stiffening penalties for blows to the head and requiring players who are injured or show signs of a concussion to sit out a play and be cleared by medical staff before returning to the field. It has also stepped up its emphasis on concussion awareness; in 2010, it began requiring all programs to have a concussion management plan.
When factoring other fall sports of soccer, field hockey and volleyball, concussion frequency also stayed stable, at 1.9 for every 1,000 exposures. David Klossner, director of health and safety for the NCAA, said in a press release that the information is helpful in monitoring trends, “we do not yet have enough information to draw final conclusions.”