FG on Fox: Do Umps Favor Aces?

As long as there are humans in charge of the strike zone, there are going to be inconsistencies. And as long as there are inconsistencies, there are going to be suspicions of bias.

Sometimes these are specific and a little paranoid. There are fans who believe umpires are biased against their favorite teams. Other times these paranoia are general and accepted without actual hard proof. For example, there’s a common belief that pitchers considered aces get the benefit of a bigger strike zone, that they’re given the benefit of the doubt around the borders, and this is just a part of the game, and there’s nothing to be done about it, really.

But is this really a part of the game?

We can accept it, or we can investigate it, and we might as well investigate it before we decide whether or not to accept it. This wouldn’t have been an option in the ’90s, when people believed Greg Maddux and Tom Glavine were getting calls. But we’ve had PITCHf/x data for the past several years, and we can make use of it toward this end. What strikes zones do aces get, relative to the non-aces?

We’ll cover the window between 2008-13. First, we must define an ace. This is subjective, but I’m going with a definition of at least five Wins Above Replacement, based on runs allowed. In other words, an ace-level season is defined as a season worth at least five WAR as a starting pitcher within the six-year window. This gives me a sample of 99 pitcher-seasons, or about 17 a year, which sounds fine to me. These seasons will be compared against other, inferior starting pitcher-seasons, of at least 50 innings each.

The next step is the more complicated step, involving a little math. For every pitcher’s season, we have to figure out what the strike zone was like that they pitched to. It turns out this is actually pretty simple. Over on FanGraphs, we offer PITCHf/x-based plate-discipline data. You can see the rate of pitches thrown in the strike zone, and you can see the rate of swings at pitches out of the strike zone. FanGraphs also offers raw strike and pitch totals. From all this information, one can calculate an “expected strike” total.

This can then be compared to the actual strike total. If a pitcher got more actual strikes than expected strikes, it can be said he pitched to a more favorable zone. If a pitcher got fewer actual strikes than expected strikes, it can be said he pitched to a less favorable zone. The theory here is that ace-level pitchers end up with more actual strikes than expected strikes, because they get more calls off the edges.

For every pitcher-season, I calculated the difference between actual strikes and expected strikes, per 200 innings. So what do we find from the resulting data?

Read the rest on FoxSports.com.




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Jeff made Lookout Landing a thing, but he does not still write there about the Mariners. He does write here, sometimes about the Mariners, but usually not.


29 Responses to “FG on Fox: Do Umps Favor Aces?”

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  1. Joe says:

    Why not give us p values if you’re going to tell us its not significant?

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  2. MrKnowNothing says:

    Feel like Dave nailed it. It’s about being in the zone first. And then it’s about looking like you’re in the zone. And you do that by hitting your spot. If it’s close but it’s clearly exactly where the C set up, I can see an ump giving the benefit of the doubt. Particularly if it’s a hitters count where the P has no incentive to throw a ball.

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    • Baltar says:

      Yes, other studies I’ve read show that pitchers with good control get the benefit of the doubt. I suppose the set of aces and the set of control pitchers has a considerable overlap, but they are not identical.

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    • RC says:

      “. If it’s close but it’s clearly exactly where the C set up, I can see an ump giving the benefit of the doubt”

      I can’t. I don’t give a crap if he hit his spot. If its not in the strikezone, its a ball.

      Bring on the robots.

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  3. DavidKB says:

    I don’t disagree with the analysis but I think it could be better tuned to get at the question that’s being asked. Using a 5 WAR cutoff is a bad choice, as it doesn’t probe the umpire’s understanding of who’s an ace, but rather FG’s understanding. It would be much better to look at Cy Young pitchers, or pitchers with big contracts, or low ERAs, or something like that. It isn’t easy to set the cutoff, but “good” is no replacement for “famed.” Another way this analysis could be done is by looking at the calls a pitcher gets before and after a major event, e.g. winning the Cy Young or signing that major contract. That shrinks down the sample size. But I think the tradeoff between the sample size being small and unrepresentative is going to plague this analysis no matter what.

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    • Good ideas. Might have to re-visit down the road! I still doubt I’ll find anything, though, but I like your train of thought.

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      • Baltar says:

        Don’t do it on Fox though, which doesn’t even work for my computer after multiple tries.
        Do it here where it belongs and will be appreciated.

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      • dl80 says:

        Jeff, it might also help to look out further from when the pitcher starts to become “known” as an ace (however that’s defined). So if a pitcher has a great year in 2009, does their zone begin to get more favorable soon after and doors it then continue to keep getting better over the next several years?

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  4. Richard says:

    You’re writing for fox? So why write in the style of ‘The Book’? It may have been a great influence on you and I, but the average Fox viewer? Slowly, slowly catchy monkey. If you want to educate first entertain, your great strength lies in humour and in drawing people in to areas they would not normally go. Don’t change your style, for the first time I found you unreadable.

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  5. Well, if you had listened to the Giants-Bridegrooms game yesterday, you might not have written this article. Bumgarner, our #1 starter and ace, got totally squeezed by the umpire yesterday.

    I’ve been for keeping umpires to call strikes even though we have equipment that can call the pitches, but this was the second game of the SERIES where the umpire was calling pitches like he was drunk or hungover or something, the umpire in the first game kept on raising the ire of the announcer with his inconsistencies, to the point where he went to verify that the the pitch was identified as a ball, while the umpire called it a strike.

    In the business world today, what would be done with metrics like this is, it is very easy now to rate each umpire on how well he is calling balls and strikes, and if he falls under a floor for that accuracy, some sort of remedial training would first be offered, leading eventually to dismissal if he can’t get with the program.

    No umpire is above the game. Some seem to act like fans are there to see them, and while I enjoy the flavor that umpires bring to the game, and the game would be diminished without them, I would much more prefer to see the game the way it should be – if it’s a ball, call a ball, if it’s a strike, call a strike – played fairly for each team, mano-a-mano, best team on that day wins. Not win because the umpire decided that the catcher made a nice move and therefore the runner is out at the plate, not win because the umpire’s strike zone changes from batter to batter. Level playing field, that’s all we ask.

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  6. Anon21 says:

    Damn, the first (and so far only) comment over there claims Tom Glavine was getting strikes eight inches outside, and that if it weren’t for officiating bias he’d have been a below-average pitcher. The nice thing about Fangraphs is that if someone brings that much stupidity in here, they immediately get their eyes torn out by angry nerds.

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    • TKDC says:

      Some people are unable to make a simple connection between two sets of facts. People naturally think Ace pitchers get better calls now. It turns out that isn’t really true. People think that Glavine and Maddux got better calls 20 years ago. What’s more likely, that there was a dramatic shift from Aces getting calls to not getting better calls or that this bias never existed?

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      • RC says:

        What’s more likely?

        That there was a dramatic shift.

        There’s been a significant shift in the strikezone over the last 5 years. To think there wasn’t any shit before that is silly.

        Also, it seems a bit silly to do this analysis on the strikezone as-called, and not as-ruled. If the “Aces” are aces because they’re pitching outside the rule strikezone and inside the called-strikezone more often than non-aces, then they’re getting more calls.

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    • anon23 says:

      “if someone brings that much stupidity in here, they immediately get their eyes torn out by angry nerds.”

      Especially if a Brave is slighted, or perceived to be slighted, in which case “angry nerds” = just Anon21.

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      • Anon21 says:

        Neat ad hom, bro. Would you like to associate yourself with the position that Tom Glavine would have been a below-average pitcher if he pitched to a normal strike zone, or are you one of those people who hates discussing baseball, but loves discussing discussions about baseball?

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  7. Matthew Murphy says:

    We know that the strike zone has gotten more reliable in the past few years, so while you never want to make a small sample even smaller, might be interesting to look at 2008-9 vs 2012-13. Probably won’t be a difference, but you could argue that any ace advantage disappeared as umps got more feedback from thw pitchfx data.

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  8. TKDC says:

    I wonder if guys that throw harder get more calls? It has to be harder to judge the faster the ball is moving.

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  9. 21_22 says:

    How much is getting hidden by summing up the difference over the entire season? I think averages (and medians) hide a lot of potentially relevant data. Aces pitch to a lot of different umpires (and catchers) in a season. What if this thought that an ace gets a better zone is because in a few games a year, they get really good zones that are readily apparent to those watching the game? Id like to see this broken down, for instance, by the number of games with a good zone or the magnitude of the good zone. What if the effect is only when pitchers have the platoon advantage?

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  10. Dan says:

    Yeah, I think the definition of “ace” in this context needs to be “pitcher who has the reputation of an ace”. Ideally, this should mean a pitcher who has dominated consistently for at least a couple seasons, not just a young player who comes out of nowhere to have a 6 WAR season. If there’s no reputation, there’s no reason for the umpires to have bias.

    Also, I think it would be interesting to look at the opposite idea: do umpires favor hitters with reputations for great batting eyes? I know when Rickey Henderson was playing, a lot of people said that he got walked on pitches that would have been called strike 3 for most other players. Is that true, and is it true for hitters today (Votto maybe)?

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  11. Stewart says:

    Can someone post a link(s) that examines the strike zones received by Maddux/Glavine. My memory and perception of the zones they seemed to “get” could use some refreshing. Thanks in advance.

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  12. Stewart says:

    Somebody must have a study of the 1995 season of Maddux, there doesn’t seem to be much pitch by pitch analysis of his year, (I don’t think that stuff existed back then) my memory is that he got more dubious strikes than the normal pitcher, but before people jump down my throat on the issue, I’d love to read more about the truth of the matter.

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