While public opinion is one way to measure the perception of a head coach, I decided to look at cold, hard data and figure out which coaches should have lost more in their careers, but haven’t.

I based this study on numberFire’s nERD score, which is our calculation of how good a team really is, based on expected point differential against a league average team. For instance, if the team's nERD is -10, they would be expected to lose by 10 points against a league-average opponent. This not only shows us a value score that combines offense and defense, it adjusts for the era as well, giving a more accurate representation of coaching value. For more info on nERD, check out our glossary.

I took each of the 73 NFL coaches who was in charge of a team for at least three years since 2000 (not necessarily consecutive), averaged their nERD rating and their win differential (wins minus losses), and compared the ranks of these two categories. Those with a higher rank in average nERD and lower rank in average win differential find themselves as the most quality coaches in process, just not in product.

So, which coaches have won but produced bad teams?