DIPS
Defense Independent Pitching Stats (DIPS) is the first ERA estimator to attempt to use the Voros McCracken. While it is named for its attempt to remove defensive support from ERA, it also removes other factors deemed outside a pitcher's control, such as sequencing and luck.
Theory on BABIP[edit]
DIPS originated from McCracken's observation that pitchers' BABIPs tended to show little persistence from year-to-year relative to walks, strikeouts, and home runs allowed. He theorized that deviations from the league average BABIP for a pitcher were due largely to factors outside a pitcher's control, such as park, defense, or luck, and should thus not be counted for or against a pitcher.
The original theory that pitchers have no control over BABIP is no longer accepted by baseball analysts; however, the observation that pitchers have much less control over BABIP than was assumed before DIPS is a fundamental part of current statistical work. Current work has a stronger focus on how much relevance deviations from average in a pitcher's BABIP have at given sample sizes.
Influence on ERA Estimators[edit]
DIPS led to a wave of other defense-independent ERA estimators, including FIP and tRA, which apply the theory of DIPS in different ways.
