What are Goals Against Average?
Goals Against Average is the average number of goals allowed per unit of regulation game time. It adjusts for the minutes the goalie plays.
A lower GAA is a sign of a goalie that allows few goals during a game. A higher GAA is a sign of a goalie that allows too many goals during a game.
GAA = (Goals Against ÷ Minutes Played) x Regulation Game Time in Minutes
- “Goals Against” are the number of goals recorded while the goalie is in the water. Include all goals against during regulation and overtime play. Do not include goals against during a shootout or when the net is empty. Rules for scoring are in the FINA rule book, Water Polo USA, and Water Polo Canada under “scoring.”
- “Minutes Played” are the total number of minutes played by the goalie. Include overtime play. Do not include the time the goalie plays during a shootout or when the net is empty.
- “Game Length” is the regulation game length in the league the goalie is playing. Olympic and FINA level games are 32 minutes of regulation time. NCAA water polo is 28 minutes of regulation time. Recreational and minor leagues may be less.
The goalie is in net for 320 minutes, allows 50 goals in that time, and regulation time for the league is 32 minutes per game:
50 goals against ÷ by 320 minutes = 0.15625.
0.15625 multiplied by 32 minutes per game is 5.
This goalie’s Goals Against Average (GAA) is 5.00.
Sources and more resources
- Wikipedia – Goals Against Average (GAA) and Water Polo Goalkeeper describe the basics of each term.
- Rules for FINA (Handbook & Rules), Water Polo Canada, Water Polo USA, and the NCAA– describes the rules of water polo and terms associated with the game.
- Statistics for the Olympics, Water Polo Canada, NCAA Men’s, and NCAA Women’s.
- TheFOSH.net – Water polo statistics from all over the US and Canada. The official statistics supplier for US Water Polo.
- Water Polo Planet – Guide to Waterpolo goalkeeping – Craig Wilson’s guide to the goalkeeper position in water polo.
- US Water Polo – Understanding the game – A summary on the game of water polo and the terms used in talking about it.