I have been critical of pitcher specific stats like: WHIP: Walks + Hits per Innings Pitched (IP). I had thought that this is On Base Average. It is not because innings include credit for outs on base: DP, CS, etc. Same for Hits / 9 Innings Pitched, which is not the same as BA.
For pitchers for whom there is play by play data, WHIP can be replaced with On Base Average and H/IP with Batting Average. It works for Bob Gibson but not for Christy Mathewson because there is not yet play by play data for Mathewson.
I do have a questions about BAbip (BA for Balls in Play). This stat is available for Gibson but not Mathewson. The equation is: (Hits - Home Runs) / (AB - HR - SO + SF)
1. Why not also add Sac bunts to the denominator?
2. Why not subtract from Home Runs: Inside the Park HR and Bounced HR (from the old rule)?