FEI is the Fremeau Efficiency Index, created by Brian Fremeau. Brian Fremeau is an author at Football Outsiders,ESPN and BCFToys. FEI is an advanced statistical measure for college football that tracks drive efficiency instead of per-play success.
S+P is created by Bill Connelly. Bill Connelly is an author at SBNation, RockMNation, Football Study Hall and Football Outsiders. S+P is an advanced statistical measure which combines success rate, explosiveness per play and opponent adjustments.
New! If you're curious what these numbers mean, here's a glossary, stolen happily from our friends at Roll Bama Roll.