On base percentage (OBP) / On base average (OBA)

Definition

In baseball statistics, on base percentage (OBP) (sometimes referred to as on base average [OBA], as the statistic is rarely presented as a true percentage) is a measure of how often a batter reaches base for any reason other than a fielding error, fielder's choice, fielder's obstruction, or catcher's interference (the latter two are ignored as either times-on-base (TOB) or plate appearances in calculating OBP). OBP is added to slugging average to determine on-base plus slugging (OPS). http: