In soccer (football), goals against average (GAA) is calculated as follows:
Goals Against Average = (goals against x game length) / minutes played.
If a goalie has been in net for 977 minutes, has allowed 18 goals in that time, and regulation time for the league they play in is 90 minutes per game:
18 goals against times 90 minute game length is 1,620.
1,620 divided by 977 minutes played is 1.658
Therefore, the goalie’s Goals Against Average (GAA) is is1.658
What is Goals Against Average?
Goals Against Average is a statistic in used in soccer football (as well as ice hockey, field hockey, lacrosse, water polo and other sports with a goalie) that is used to put a goalie’s number of goals allowed into perspective with their total playing time.
It is intended to give a measure of how many goals the goalie allows per unit of regulation game time.
It is considered one statics among a number of other ones, including win/loss ratio and save percentage that are used to help measure a goalie’s capability.
What counts as a “Goal Against”?
In soccer, a “goal against” is a goal that occurs while the goalie is assigned the position of the goalkeeper.
If the goalie is not on the field of play at the time when the goals happens, a goal against the team does not cont against the goalie’s GAA.
Rules for what qualifies as a goal can be found in the FIFA laws of the game (other leagues with alternative rules may have different scoring regulations).
What counts as a “Minute Played”?
Each minute that the goalie is an active player in a game is counted as a “minute played”.
What is “Game Length”?
Game length varies depending on the league.
FIFA level matches have a game length of 90 minutes (2 halves of 45 minutes). Recreational leagues may have shorter halves.
- Wikipedia – Goals Against Average (GAA)
- FIFA – Laws of the Game
- Wikipedia – Goalkeeper (Association Football)
- MLS Soccer – Player Stats (season)