This story appears in ESPN The Magazine's Feb. 8 Super Bowl 50 Issue. Subscribe today! IN THE COMING DAYS, Bengals offensive coordinator Hue Jackson is likely to accept a job at the helm of an NFL team, bolstering the ranks of black head coaches. Since the league implemented the Rooney Rule in 2003, requiring owners to interview minority candidates, the number of nonwhite head coaches has grown, from two to six this past season. The policy is widely praised as a triumph of leadership; some even argue that it's no longer needed, contending that the league has solved its diversity problem.  In truth, the problem still exists -- and it might be worse than previously understood. According to new research from professors at Georgetown, George Washington, Emory and Iowa State University, white position coaches and assistants in the NFL are more than twice as likely to be promoted to coordinator than their black counterparts, regardless of their...