# Glossary

3&Out% — This is an abbreviation for a drive that ends with a punt after three offensive plays. Its formula is three and outs ÷ drives.

4D — This is an abbreviation for a drive that ends when an offense fails to convert a fourth down.

AdjO — This is an abbreviation for adjusted offensive efficiency. This is adjusted offensive points per drive multiplied by ten.

AdjD — This is an abbreviation for adjusted defensive efficiency. This is adjusted defensive points per drive multiplied by ten.

Av. Yds — This is an abbreviation for available yards at the start of a drive. If a team starts on its own 20, there were 80 available yards on that particular drive.

Drive — Any possession with an offensive play is considered a drive. All drives have nine possible outcomes. It can be calculated by adding up scoring drives, punts, missed field goals, turnovers, and time-expiring drives.

Efficiency — This measures how many points a team scores or allows per ten drives. It provides a more accurate measurement of a team’s ability than points per game. On average, an offense can expect to play approximately ten statistically significant drives per game. This measurement mimics the equation created by Dean Oliver to gauge efficiency in basketball. Basketball’s efficiency formula is points per possession × 100. Football’s efficiency formula is points per drive × 10.

End — The average number of yards a team is from the end zone when their drive ends. The formula for this is {available yards – (rushing yards + passing yards + penalty yards)} ÷ drives.

FGM — This is an abbreviation for a made field goal.

eTO% — Effective turnover percentage; eTO% includes safeties that occurred on offensive plays and failed fourth down conversions. Its formula is (loss of downs + fumbles lost + interceptions + safeties) ÷ drives. This formula counts failed fourth down conversions and safeties as turnovers because the offense’s intent was to retain possession.

Half — This is an abbreviation for a time-expiring drive. Please reference the definition for time-expiring drives to read about the criteria that determine statistically significant drives at the end of the second and fourth quarters.

Luck — This measures the difference between a team’s winning percentage and its expected winning percentage. Its formula is winning percentage – (offensive points per drive 2.37) ÷ {(offensive points per drive 2.37) + (defensive points per drive 2.37)}. It can be found in the Adjusted Efficiency Rankings.

MFG — This is an abbreviation for a missed field goal.

Mgn. — This is an abbreviation for scoring margin; the listed margin on a drive chart is simply the home team’s score – the away team’s score.

OppO — This is an abbreviation for the strength of the opposing offense.

OppD — This is an abbreviation for the strength of the opposing defense.

Pass% This is an abbreviation for the percentage of passing plays run. Its formula is passes ÷ (passes +rushes).

Plays/10 — This is an abbreviation for the number of plays run per ten drives. Its formula is (passes + rushes) ÷ drives.

• Pass/10 — This is an abbreviation for the number of passing plays per ten drives. Its formula is passes ÷ drives.
• Rush/10 —This is an abbreviation for the number of rushing plays per ten drives. Its formula is rushes ÷ drives.

Possessions occur when a team has the ball and an opportunity to score a touchdown. All drives are possessions. Not all possessions are drives because a team can score a touchdown without running an offensive play.

Pts/Dr — Points per drive; its formula is {(FG × 3) + (TD × 7)} ÷ drives.

Punt% — Punt percentage; the formula for Punt% is punts ÷ drives.

Pyth — This is an abbreviation for Pythagorean Expectation. It was developed by Bill James. In baseball, the purpose of this formula is to estimate the number of games a team should have won based on runs scored and runs allowed. Its formula in the Adjusted Efficiency Rankings is (AdjO 2.37) ÷ {(AdjO 2.37) + (AdjD 2.37)}. This formula is also used in calculating strength of schedule and luck.

Rush% This is an abbreviation for the percentage of rushing plays run. Its formula is rushes ÷ (passes +rushes).

SAF — This is an abbreviation for a drive ending in a safety. This excludes safeties occurring on non-offensive plays.

Score% — Score percentage; its formula is (TD + FG) ÷ drives.

SOS — This abbreviation is for strength of schedule. It also uses the Pythagorean Expectation formula. Its formula is (OppO 2.37) ÷ {(OppO 2.37) + (OppO 2.37)}.

Start — The average number of yards a team is from the end zone when their drive begins. The formula for this is available yards ÷ drives.

Statistically Significant Drives — Drives that take place when a game is close. Football Outsiders’ criteria for statistical significance effectively filters relevant offensive and defensive drives. Here is the definition of a statistically significant drive:

• Drives beginning in the first quarter with a margin of 28 points or less.
• Drives beginning in the second quarter with a margin of 24 points or less.
• Drives beginning in the third quarter with a margin of 21 points or less.
• Drives beginning in the fourth quarter with a margin of 16 points or less.
• Drives beginning in the final two minutes of a game with a scoring margin of 8 points or less.
• This criterion has been added on this site because it’s extremely difficult for a team to overcome a two possession deficit with under two minutes remaining. This means a team must score at least one touchdown, recover an onside kick, and make a field goal or score another touchdown in two minutes or less.

TD% — Touchdown percentage; the formula for TD% is touchdowns ÷ drives.

Time-Expiring Drives — Drives that end when an offense attempting to score has its possession ended by the expiration of time at the end of the first or second half. Time-expiring drives get filtered based on the following criteria:

• Drives where a quarterback takes a knee. It doesn’t matter what plays preceded the quarterback kneel. The one exception to this rule occurs when a team take a knee in the middle of the field to put its place kicker in a more advantageous position to make a field goal.
• Drives ending with less than 1:00 minute remaining in the second and fourth quarters get expunged when a team does not pass or attempt to score.
• Time-expiring drives in the second and fourth quarter that end with at least three consecutive running plays.
• If a team passes on a time-expiring drive where no knee is taken, this must count as statistically significant because the available information indicates that an offense attempted to score.
• If a team is sacked on a time-expiring drive where no knee is taken, that also must count as a statistically significant drive because all sacks get counted as passing plays.

TO% — Turnover percentage; the formula for TO% is (interceptions + fumbles lost) ÷ drives.

Yds% — Yards percentage; its formula is (passing yards + rushing yards) ÷ available yards.

• PYds% — Rushing yards percentage; its formula is rushing yards ÷ available yards.
• RYds% — Passing yards percentage; its formula is passing yards ÷ available yards.

Yds/Dr — Yards per drive; its formula is (passing yards + rushing yards) ÷ drives.

• PYds/Dr — Passing yards per drive; its formula is passing yards ÷ drives.
• RYds/Dr — Rushing yards per drive; its formula is rushing yards ÷ drives.

Yds/Play — Yards per play; its formula is yards ÷ plays.

• PYds/Play — Passing yards per play; its formula is passing yards ÷ plays.
• RYds/Play — Rushing yards per play; its formula is rushing yards ÷ plays.