As the NFL continues to take steps toward concussion prevention and treatment, a new report alleges that the league's past data regarding head injuries is incomplete.
According to Alan Schwarz, Walt Bogdanich and Jacqueline Williams of the New York Times, confidential data suggests that more than 10 percent of concussions that occurred from 1996 to 2001 were not included in studies, which made the NFL's concussion issue seem less significant than it really was.
The league admitted that not every team submitted full data since teams were not required to but insisted that it wasn't part of a conscious effort to alter the statistics.