Now, Dr McKee admit that there is a definitive bias in her sample group. After all, most of the brains she looked at were donated by the families of ex-players who were already showing signs of CTE. But that doesn’t invalidate the findings. In fact, with more than 50% testing positive, the link to playing football is clear. Of the group, there were 44 linemen affected. Running backs were next, with 20 , and defensive backs offered 17 cases. Quarterbacks, wide receivers, and tight ends had some of the fewest, with seven, five, and two instances respectively. The NFL is current addressing the ongoing situation, but Dr. McKee doesn’t mince words about her findings. “It is no longer debatable whether or not there is a problem in football — there is a problem,” she said.