Games behind

In the below standings from the 1994 Major League Baseball season, the Atlanta Braves are six games behind the Montreal Expos. Atlanta would have to win six games, and Montreal would have to lose six games, to tie for first. The leading team is zero games behind itself, and this is indicated in standings by a dash, not a zero.

Games behind is calculated by using either of the following formulas, in which Team A is a leading team, and Team B is a trailing team. Example math in this section uses the above standings, with Montreal as Team A and Atlanta as Team B.

${\displaystyle {\text{Games Behind}}={\frac {({\text{Team A's wins – Team A's losses}})-({\text{Team B's wins – Team B's losses}})}{2}}}$

${\displaystyle {\text{Games Behind}}={\frac {({\text{74 – 40}})-({\text{68 – 46}})}{2}}={\frac {\text{34 – 22}}{2}}={\frac {12}{2}}=6}$

Alternately:

${\displaystyle {\text{Games Behind}}={\frac {({\text{Team A's wins – Team B's wins}})+({\text{Team B's losses – Team A's losses}})}{2}}}$

${\displaystyle {\text{Games Behind}}={\frac {({\text{74 – 68}})+({\text{46 – 40}})}{2}}={\frac {\text{6 + 6}}{2}}={\frac {12}{2}}=6}$

Notes:

• It can alternately be said that Montreal is six games ahead of Atlanta.
• A games behind situation can change rapidly when two teams contesting for the lead play each other. For example, Atlanta could cut Montreal's lead in half (to three games) by sweeping a three-game head-to-head series.
• The leading team, in terms of games behind, is the team with the best won–loss difference. This is not always the team with the most wins. For example, a team with an 80–70 record (10 more wins than losses) would be one game behind a team with a 79–67 record (12 more wins than losses).

A games behind calculation can be misleading when attempting to compare teams that have played an unequal number of games. This is because the games behind calculation simply computes the difference between wins and losses for each team, and then averages those two numbers. Essentially, this treats each unplayed game as being a ​¹⁄₂ win and a ​¹⁄₂ loss.

In an extreme example, attempting to compare the records of the 2007 New England Patriots (16–0; 1.000 winning percentage) and the 1972 Detroit Tigers (86–70; .551 winning percentage) finds that the teams are equivalent per a games behind calculation, as each team won 16 more games than it lost. However, the Tigers played 140 more games than the Patriots. The Patriots' 140 "unplayed" games are essentially treated as 70–70; indeed, if the 16–0 Patriots had 70 more wins and 70 more losses, their 86–70 record would match that of the Tigers.

In reality, teams in an actual sports league can have an unequal number of games played due to various scheduling anomalies, postponements, or cancellations. This can result in:

• Two teams with different winning percentages may be tied in terms of games behind. For example, Team A at 6–4 would be tied with Team B at 4–2, in terms of games behind. However, Team B has the better winning percentage, at .667 compared to .600 for Team A.
• A team with a lower winning percentage may lead (in terms of games behind) a team with a higher winning percentage. For example, Team A at 6–4 would lead Team B at 2–1 by a half-game when calculating games behind. However, Team B has the better winning percentage at .667, compared to .600 for Team A.

Such conditions have occurred multiple times in major sports leagues, examples include:

Leagues generally use winning percentage to order teams in official standings; however, standings appearing in newspapers or online may order teams based on games behind.

NBA standings in November 1965 as published in The Minneapolis Star

The games behind calculation is often used in professional baseball and basketball, where tie games are not permitted.[lower-alpha 1] Standings for these sports appearing in print or online during a season usually will have teams ordered by winning percentages, with a "GB" column provided as a convenience to the reader. Games behind is used less often in American football, where ties are possible but relatively uncommon. Games behind is rarely used in ice hockey and soccer, where ties are or were traditionally common and standings points are typically used.

National Football League

NFL standings in October 1972 as published in the Tampa Bay Times

National Football League (NFL) standings sometimes report games behind, although the statistic is not emphasized; winning percentage is used, computed from each team's win–loss–tie record. This is especially true since the introduction of the bye week in 1990, exacerbating differences in the number of games that teams have played at various points in time, and since tied games (while highly uncommon since the introduction of overtime in the regular season starting in 1974) do still occur on occasion. Games behind is omitted from standings on the NFL's website and is absent from most published standings.

• Magic number (sports), the number of wins needed to clinch a championship

• GB glossary entry at baseballprospectus.com