Today, each FCS team has an FPI rating based on the final score of games dating back four years. As with FPI for FBS teams, the rating is a measure of team strength and represents the expected scoring margin against an average FBS opponent.
For example, North Dakota State enters the season with an FPI rating of plus-0.9, meaning if the Bison were to play an average (or 64th-ranked) FBS team, they would be favored slightly on a neutral field. In the coming season, there are 32 FCS teams with a higher FPI rating than the weakest FBS team and seven FBS-vs.-FCS games in which the FCS team has at least a 25 percent chance to win.
By capturing the true strength of each FCS team, we are also improving the accuracy of FPI’s FBS ratings and game predictions. With the updated formula, the team FPI favored continued to win 75 percent of FBS-only games since 2005, but predicted scoring-margin errors decreased compared with the previous system.
After accounting for the relative strength of FCS teams, Iowa State entered its home game against North Dakota State with a 66 percent chance to win. After losing to the Bison, the Cyclones fell 15 spots in FPI, and what was once a historically crippling loss was treated no differently than a loss to about the 66th-ranked FBS team.