In sports in Canada and the United States, the phrase games behind or games back (often abbreviated GB), is a common way to reflect the gap between a leading team (said to be that many games ahead or GA) and another team in a sports league, conference, or division. It is determined by adding the absolute difference in wins between a leading team and the team of interest to the absolute difference in losses between the two teams, and dividing the sum by two. The leading team itself is always zero games behind. Usually this is indicated in tables by a dash rather than a zero.
GB is calculated using the following formula, in which TeamA is the first-place team, and TeamB is the trailing team:
For example, if the Cleveland Indians are three games behind the Chicago White Sox for first place, Cleveland would have to win three games, and Chicago would have to lose three, to tie for first. A "games behind" situation changes rapidly when two teams contesting the lead play each other since a zero sum game plays out. In this case, Cleveland would pull even with Chicago in a clean sweep of all three games.
It is often used in professional baseball and basketball, where tie games are not permitted, and to a slightly lesser extent in American football where ties are rare (when they do occur, they are counted as half a win and half a loss when calculating GB). Usually, in tables of standings in newspapers and magazines kept during the season, teams are ordered by the teams' winning percentages, with the number of games they are behind the division leader supplementing the table. On rare occasions, it is possible (and has occurred) for the team with the second best winning percentage to lead the team with the best winning percentage in terms of games back. This usually occurs during the early portion of a season when teams have played an uneven number of games. For example, if Team A has a record of 23–13 and Team B has a record of 26–15, Team A would be recognized as having a better record by virtue of their .639 win percentage to Team B's .634 percentage. However, in the standings, Team A would still be one-half game behind Team B, though they would be ordered ahead of Team B.
Also, in some rare situations, also caused in the early season when teams play an odd number of games, a team with fewer wins could potentially be ahead of a team with more wins. For example, if a team is 26–15, but another team is 25–13, the team with a record of 25–13 is technically one-half game ahead of the 26–15 team, despite having fewer wins on the season.
The "games behind" number is sometimes made in reference to a standard "winning percentage", although in this particular context, the word "behind" is replaced by "under" or "below". In making this calculation, however, the division by two is not done. For example, a team with a record of 19 wins and 20 losses is considered as being "one game under .500", in contrast to being "one-half game behind" a team with a ".500" record of 20 wins and 20 losses.
This statistic is now being calculated somewhat differently in baseball. Traditionally games behind was calculated with respect to the team with the highest standing in the league (up through the 1968 season), or to the team with the highest standing in the division (1969 season and later). But, for the 1994 season Major League Baseball's two leagues split into three divisions each, and added a wild card team to the playoffs. It now became common for the media to publish an additional set of standings for the wild card race. It included all teams from a league, with the exception of the division leaders, and games behind was calculated with respect to the team with the highest standing in the division. Things changed again in 2012 when Major League Baseball added a second wild card team. Now games behind is shown in the media as calculated in two different ways. This is either with respect to 1) the team with the highest standing in the division, or 2) the team with second highest standing in the wild card race. Currently these are both called Games Behind or GB in the media.
See also 
- Magic number (sports), number of wins needed to clinch a championship