On a side note, I really hate the expression “eating crow”. And I only see it on this site.

]]>So would one expect regression in Ichiro’s BABIP (in the best possible meaning of the word) or is this the sign of a rapidly declining skillset (or both)?

]]>1. The league-wide BABIP already reflects the overall amount of shifting being done, so comparing BABIP to xBABIP for an individual player where his xBABIP has been calculated from a regression over the entire league (i.e. one which includes both shifted and non-shifted defenses) may not actually tell us how the shift is affecting that player unless we know exactly how many more shifts he is facing than league average (and this is before we even consider the small sample size issues with an individual BABIP over even an entire season).

2. The year-to-year volatility in the calculated xBABIP constants makes me rather uneasy. There doesn’t seem to be a good real-world explanation for why e.g. OFFB should have led to 60% more hits in 2010 than 2009, which leads me to believe the regressions may be over-fit.

3. If 2012 is the year of the shift as many are saying, shouldn’t we expect the league-wide BABIP to be lower than last year? I find it puzzling that it isn’t, unless (drum roll) the general effectiveness of the shift has been overstated.

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