FEI is a college football rating system based on opponent-adjusted drive efficiency. Approximately 20,000 possessions are contested annually in FBS vs. FBS games. First-half clock-kills and end-of-game garbage drives and scores are filtered out. Defensive Efficiency (DE) is the value generated by a team's defense per non-garbage possession relative to national average scoring rates by starting field position. DFEI is value generated per possession adjusted for the strength of opponent offenses faced.
Available Yards Percentage (DAY) is the total number of yards surrendered by the defense divided by the number of yards available to be earned based on starting field position. Value Drive Rate (DVD) is the percentage of opponent offensive drives that begin at least 50 yards from the end zone and reach the team's 30-yard line. First Down Rate (DFD) is the percentage of opponent offensive drives that result in a touchdown or at least one first down. Touchdown Rate (DTD) is the percentage of opponent offensive drives that result in a touchdown. Touchdown Rate After First Down (DTF) is the percentage touchdowns surrendered on opponent offensive drives that earn at least one first down. Turnover Rate (DTO) is the percentage of opponent offensive drives that result in a fumble or interception.