Goals against average - Wikipedia
en.wikipedia.org › wiki › Goals_against_averageGoals Against Average (GAA) also known as "Average Goals Against" or "AGA" is a statistic used in field hockey, ice hockey, lacrosse, soccer and water polo that is the mean of goals allowed per game by a goaltender/goalkeeper (depending on sport). GAA is analogous to a baseball pitcher's earned run average (ERA). In Japanese, the same translation (防御率) is used for both GAA and ERA, because of this.