Defense Independent Pitching Statistics

Defense Independent Pitching Statistics

In baseball, defense-independent pitching statistics (DIPS) measure a pitcher's effectiveness based only on plays that do not involve fielders: home runs allowed, strikeouts, hit batters, walks, and, more recently, fly ball percentage, ground ball percentage, and (to much a lesser extent) line drive percentage. Those plays are under only the pitcher's control in the sense that fielders (not including the catcher) have no effect on their outcome.

Several sabermetric methods use only these "defense-independent" pitching statistics to evaluate a pitcher's ability. The logic behind using only these statistics is that once a ball is put in play, most often the pitcher has no effect on the resultant fielding of the ball. But defense-dependent statistics, such as the rate of hits allowed on balls put into play, are sometimes affected by the quality and/or arrangement of the defense behind the pitcher. For example, an outfielder may make an exceptionally strong diving catch to prevent a hit, or a base runner may beat a play to a base on a ball thrown from a fielder with sub par arm strength. Defense-independent statistics such as walks and strikeouts are determined almost solely by the pitcher's ability level.