Re: Homer Bailey: 2012 vs 2013
Doug, aside from the small sample size, could there be some selection bias here as well? That is, do pitchers generally throw harder in April than they do over the course of a full season?
If I recall, most pitchers lose velocity over the course of the year, suggesting that a more appropriate comparison would be to his April 2012 rather than the full season. I imagine that velocity and movement both stabilize rather quickly. So assuming you have a few hundred pitches, I imagine you've already got enough to deal with random variation. The bigger concern is probably having samples that aren't systematically biased due to selection.
(All that said, just browsing his Pitch f/x data, there did not appear to be a significant, consistent decline in velocity over the course of 2012. But there did appear to be some reasonable variation throughout the year.)
Games are won on run differential -- scoring more than your opponent. Runs are runs, scored or prevented they all count the same. Worry about scoring more and allowing fewer, not which positions contribute to which side of the equation or how "consistent" you are at your current level of performance.
Last edited by RedsManRick; 04-18-2013 at 12:15 PM.