Kevin Guskiewicz, the research director at the Center for the Study of Retired Athletes, a frequent critic of the MTBI committee, says the NFL should consider evidence beyond brain slices. Surveying retired players, Guskiewicz found a three-fold increase in clinical-depression rates after three or more concussions. In June he presented his findings at the first-ever "concussion summit" in Chicago, a gathering of more than 250 clinicians, player representatives, and team doctors and trainers convened by NFL commissioner Roger Goodell to discuss traumatic head injuries. Casson dismissed Guskiewicz's results as well, saying the study relied too heavily on anecdotal information. "The data is there," Guskiewicz counters. "Now, hopefully, physicians and trainers will put it to good use."