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An Advanced College Football Stats Glossary

Here is a glossary for the terms used in the 2013 college football season previews at SB Nation.

Adj. Line Yards: An opponent-adjusted version of the line measure derived from the formula found here. The idea is to divvy credit for a given rush between both the runner and the blockers.

Adj. Pace: Part of the offensive footprint, this takes into account both the number of plays a team attempts and the type of play. Since passes, on average, take up less time (thanks to the fact that 30-50 percent of them are incomplete and stop the clock), pass-heavy offenses are prone to run more plays, therefore limiting the effectiveness of a general plays-per-game measure. Adj. Pace takes a team's run-pass ratio into account.

Adj. POE: An opponent-adjusted "Points Over Expected" measure for running backs that looks both at what a runner gained and what would have been expected given the opponents involved. For more information, start here.

Adj. Points: A look at how a team would have performed in a given week if playing a perfectly average team, with a somewhat average number of breaks and turnovers. The idea for the measure is simple: what if everybody in the country played exactly the same opponent every single week? Who would have done the best? It is an attempt to look at offensive and defensive consistency without getting sidetracked by easy or difficult schedules. And yes, with adjusted score you can allow a negative number of points. For more, start here.

Adj. Record: A derivation of Adj. Points, Adj. Record is based on single-game S&P+ performances. This is the record a team would have had playing a perfectly average team, with a perfectly average number of breaks, in each week of the season. Adj. Record gives you a different way to visualize the impact of both team consistency and schedule strength. Since both teams in a given game are being compared to a baseline average (instead of each other), it is conceivable that both teams could end up with an adjusted win or loss.

Adj. Sack Rate: An opponent-adjusted measure of sack rates.

Adj. Score: See Adj. Points.

Adj. TO Margin: What a team's turnover margin would have been if they had recovered exactly 50 percent of all the fumbles that occurred in their games. If there is a huge difference between TO Margin and Adj. TO Margin (in other words, if fumbles, dropped interceptions, or other unlucky bounces were the main source of a good/bad TO margin), that suggests that a team's luck was particularly good or bad and might even out the next season.

Adj. Yards Per Target: A look at a receiver's total receiving yards divided by the number of times he was targeted. Slight adjustments are made for the percentage of times a receiver was targeted on standard ("%SD") and passing downs. Players targeted more on passing downs are likely to have a lower overall per-target average, since passing is more difficult on passing downs.

Bend-Don't-Break: Part of the defensive footprint, this is a comparison of a team's Def. Success Rate (efficiency) to its Def. PPP (explosiveness). The higher the number, the higher percentage of a team's overall S&P was made up by success rate, i.e. the more willing a team was to sacrifice efficiency to prevent big plays. (The lower the number, the more likely a team was to take aggressive risks.)

Covariance: Covariance is a statistical tool that provides a measure of the strength of the correlation between two or more sets of random variates. For these purposes, it is used to compare a team's performance (using opponent-adjusted Adj. Score) to the quality of the opponent at hand. Some teams play their best games against their worst opponents, and some teams do the opposite. This measure is used for both the offensive and defensive footprint. For more, go here.

Diff. Net Points: A raw average of the points an offense scores on a given drive compared to the points it would be expected to score based on starting field position.

F/+. The official college football ratings of record at Football Outsiders. F/+ is a combination of the Brian Fremeau's Fremeau Efficiency Index (FEI) and my S&P+.

Fremeau Efficiency Index (FEI): FEI considers each of the nearly 20,000 possessions every season in major college football. All drives are filtered to eliminate first-half clock-kills and end-of-game garbage drives and scores. A scoring rate analysis of the remaining possessions then determines the baseline possession efficiency expectations against which each team is measured. A team is rewarded for playing well against good teams, win or lose, and is punished more severely for playing poorly against bad teams than it is rewarded for playing well against bad teams. For more, go here.

Go After the Ball: Part of the defensive footprint, this looks at a team's forced fumbles, interceptions and passes broken up. In other words, it looks at their ability to go after the ball. The higher the number, the more they got their hands on the football.

Highlight Yards: The portion of a given run that is credit only to the running back; after a certain number of yards, the line has done its job, and most of the rest of the run will be determined by the running back himself. For more information, start here. An important note, however: a player's per-carry highlight yardage is now calculated as follows: Highlight Yards divided by Opportunities. In this case, Opportunities mean only the carries in which the offensive line "did its job," i.e. carries that went at least five yards. With a different denominator, then, it is possible for a player's Highlight Yards per carry to be much higher than his overall yards per carry.

Need for Blitzes: Part of the defensive footprint, this compares a team's standard downs sack rate to its passing downs sack rate. The lower the number, the more they were able to generate pressure on standard downs, and the less need for blitzes.

Opportunity Rate: This is the percentage of carries in which the offensive line "does its job" and produces at least five yards of rushing for the runner. (Generally speaking, the first five yards are considered the line's responsibility, the next five are split evenly between the runner and the line, and anything over 10 yards is all on the runner.) See Highlight Yards and Adj. Line Yards for more information.

Passing Downs: Second-and-7 or more, third-and-5 or more, or fourth-and-5 or more. These are downs in which passing is easily the most likely option for gaining the necessary yardage, and defenses hold the upper hand. Offenses typically throw about 67 percent of the time on passing downs.

Power Success Rate: As used in Football Outsiders' pro line stats, this is the percentage of runs on third or fourth down, two yards or less to go, that achieved a first down or touchdown. Also includes runs on first-and-goal or second-and-goal from the two-yard line or closer.

PPP: Points per play is an explosiveness measure derived from determining the point value of every yard line (based on the expected number of points an offense could expect to score from that yard line) and, therefore, every play of a given game.

PPP+: An opponent-adjusted version of PPP. As with most other "+" measures, it is built around a baseline of 100.0. Anything over 100.0 is better than average, anything below 100.0 is worse than average.

S&P+. A college football ratings system designed by me and derived from the play-by-play and drive data of all 800+ of a season's FBS college football games (and 140,000+ plays). For more, go here.

Standard Downs: First downs, second-and-6 or fewer, third-and-4 or fewer, and fourth-and-4 or fewer. These are the downs in which the offense could conceivably either run or pass and therefore has an overall advantage over the defense. Offenses typically run about 60 percent of the time on standard downs.

Stuff Rate: This is the percentage of runs where the runner is tackled at or behind the line of scrimmage. Since being stuffed is bad, offenses are ranked from stuffed least often (No. 1) to most often (No. 125); for defenses, the opposite is true.

Success Rate: A common Football Outsiders tool used to measure efficiency by determining whether every play of a given game was successful or not. The terms of success in college football: 50 percent of necessary yardage on first down, 70 percent on second down, and 100 percent on third and fourth down.

Success Rate+: An opponent-adjusted version of Success Rate. As with most other "+" measures, it is built around a baseline of 100.0. Anything over 100.0 is better than average, anything below 100.0 is worse than average.

Turnovers Luck: Presented in Points Per Game fashion, Turnovers Luck looks at the difference between a team's Turnover and Adj. TO Margins and, using the average point value of a turnover (~5.0 points), projects how many points a team gained or lost per game last season.

Yards Per Point: A measure long tracked by Phil Steele as a means of looking at teams that were a little too efficient or inefficient the previous season. A positive YPP Margin means a team's offense was less efficient than opponents' offenses, and to the extent that luck was involved, their luck might even out the next year.