0 of 10

Tyler Smith/Getty Images

Games are won on the field, but part of that equation is the impact of defensive coordinators. They're calling the shots, picking the right coverages and blitzes to stall an opponent's drive.

Hanging on to these coaches is not easy. Many eventually move to leading roles. Others, however, seem content to remain coordinators for most of, if not all of, their careers.

Factors used to determine the 10 best in college football include a coach's overall success, aided by total and scoring defense, Football Outsiders' S&P+ defensive ratings and red-zone numbers. Recent and projected performance in 2016 were given extra weight.

Only current coordinators were eligible for a spot, so Kirby Smart, D.J. Durkin and Will Muschamp simply receive a mention here.