In baseball statistics

Baseball statistics

Statistics play an important role in summarizing baseball performance and evaluating players in the sport.Since the flow of a baseball game has natural breaks to it, and normally players act individually rather than performing in clusters, the sport lends itself to easy record-keeping and statistics...

, batting average against (denoted by BAA or AVG), or opponents' batting average (denoted by OBA) is a statistic that measures a pitcher

Pitcher

In baseball, the pitcher is the player who throwsthe baseball from the pitcher's mound toward the catcher to begin each play, with the goal of retiring a batter, who attempts to either make contact with the pitched ball or draw a walk. In the numbering system used to record defensive plays, the...

's ability to prevent hits during official at bat

At bat

In baseball, an at bat or time at bat is used to calculate certain statistics, including batting average, on base percentage, and slugging percentage. It is a more restricted definition of a plate appearance...

s. It can alternatively be described as the league's hitters' combined batting average against the pitcher. It is calculated as: Hits Allowed divided by (Batters Faced minus Walks minus Hit Batsmen minus Sacrifice Hits minus Sacrifice Flies minus Catcher's Interference).

Mathematically speaking: