BABIP - QMIND-Team/Sabermetrics GitHub Wiki

Batting Average Fields in Play (BABIP)

Formula: (H-HR)/(AB-K-HR+SF) Methodology: Batting average excluding homeruns and strikeouts while counting sacrifice flies as outs. BABIP is essentially the batting average for when the ball is hit into play. Purpose: To measure the batting average for only balls that are impacted by the defence Acronyms Hits (H): The hitter must reach first base, or any following base after hitting the ball. Home runs (HR): The batter hits the ball out of the field which allows all of the offensive players on the field to automatically score. At bat (AB): When a batter is placed against a pitcher. A batter would not receive credit for an AB if his plate appearance ends in one of the following circumstances.

1. The pitcher throws outside of the strike zone four times in a row which causes a “walk”
2. The player is hit by the pitcher
3. Performs a sacrifice fly
4. Awarded first base due to interference
5. Is replaced by another hitter before his bat is completed Strikeouts (K): Occurs when a batter accumulates 3 failed swings at an AB which then terminates the AB attempt Sacrifice Fly (SF): When the batter hits the ball into the outfield to be caught but gives time for another other offensive players to score. Factors that affect BIPIP: Luck: The BIBIP of players tends to fluctuate around their mean A Pitcher’s Defence: A good defence is more likely to cause outs, which would decrease the BABIP of a pitcher. Talent of Batter: Batters who are fast and have high accuracy tend to have a higher BABIP How can this be useful? • Since pitchers have little control where the ball goes after it is in play and the strength of their defence, their BABIP is mostly out of their control. A pitcher with a high BABIP would presumably perform better in the future or on a stronger team. • BABIP takes a long time to stabilize, so if a new batter has high offensive numbers and a high BABIP, then the success of the player may be partially be due to luck.