Average nERD: -5.06 (59th)
Average Win Differential: -2.80 (51st)

Of all the coaches that came from the Bill Parcells coaching tree, Eric Mangini is not one of his most decorated pupils, despite having sustained a 10-year career as a coordinator or more since 2005. That year, Mangini was promoted from the Patriots’ defensive backs coach to the defensive coordinator job. From this spot, he would earn a job as the head coach of the rival New York Jets, eventually implicating his former boss Bill Belichick in the “Spygate” scandal. That didn’t help his team, unfortunately, as his Jets made the playoffs just once between 2006 and 2008. The Cleveland Browns gave him a shot in 2009, but after two consecutive 5-11 seasons, Mangini was let go.

Mangini had just two winning seasons out of five as a head coach, but his nERD scores are even worse. He had no years with a team that earned positive nERD, as his 2006 Jets even attained just a mediocre -0.55 nERD. Two years saw Mangini’s teams with a -5.00 nERD or lower, and his 2009 Browns had the 10th-worst nERD of all time, with a -12.58. Despite excellent teachers, the student never became the master in Mangini’s case.