Maybe Zito isn't 'Back to His Old Habits'

So I probably should be studying for finals, but FanGraphs has really been getting in the way of that. I was looking at the team leaderboards under infield fly % (riveting stuff, I know), and noticed something odd. In 2009, the lowest team IFFB% is 11.9%. The bottom 5 are all between that and 15.1%. In 2008, the highest team IFFB% was 12.1%. Just eye-balling it, the data from 2004-2008 is all very similar, but there’s a huge jump in 2009 for whatever reason. 2002 and 2003 are slightly higher than ’04-’08, but only by a tiny amount.

This reminded me of Eric Seidman’s Zito post on FanGraphs from a few days ago, which focused a lot on Barry Zito’s IFFB% (why do I always quote other StatSpeakers? It’s getting kind of weird at this point). If that stat is inflated in general, then maybe Zito isn’t doing anything differently, it’s just that his data are inflated along with the rest of the league’s.

This is just something I noticed and wanted to throw up on here (not literally) to maybe get some feedback. Once I have some more free time, I’ll look deeper into this and see what the full effect really is.

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4 Responses to Maybe Zito isn't 'Back to His Old Habits'

  1. Matt Swartz says:

    Yeah, I noticed the crazy IFFB% numbers this year, and I was considering writing something on it but hadn’t gotten a chance.
    It’s a very interesting question. You mention that it could be a data issue– and maybe it is. But I don’t quite see how. If the infielder catches the popup, it is an infield flyball, and if they don’t, it’s not. How could there be a measurement error?
    Maybe pitchers are making adjustments to hitters thanks to new data out there that hitters haven’t adjusted to yet. Looking back through April of previous years, there was nothing like this IFFB% so there would need to be something about this year. Without running a test, I don’t see how the difference wouldn’t be statistically significant.

  2. dkappelman says:

    I’m currently investigating why this my be the case because IFFB% on average has almost doubled this season so far. It seems extremely fishy and it’s not just us, THT is showing the same numbers so it’s not a calculation error. Look for a response on fangraphs this week. I’ll make a post when I find out what’s going on.

  3. Matt Swartz says:

    Thanks, please investigate this. I see that flyball BABIP this year is right around last year’s average (.144 in ’08 and .145 in ’09). I am not quite sure what is going on, since if hitters had suddenly been tricked into popping up more, their overall flyball BABIP would fall too.

  4. dad says:

    yes u SHOULD be studying for finals!!! dad

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