Does Race Influence Umpires?

This is the question addressed in a new study by economists Christopher Parsons, Johan Sulaeman, Michael Yates, and Daniel Hamermesh.

In the new study, Hamermesh’s team analyzed the calls on 2.1 million pitches thrown in the Major League between the 2004 and 2006 seasons. Controlling for all other outside factors, such as the pitcher’s tendency to throw strikes, the umpires’ tendency to call strikes and the batter’s ability to attract balls, researchers found evidence of same-race bias — and the data revealed that the bias benefits mostly white pitchers. Not surprising, since 71% of MLB pitchers and 87% of umpires are white.

The highest percentage of strikes were called when both the home-plate umpire and pitcher were white, and the lowest percentage were called between a white ump and a black pitcher. The study also found that minority umpires judged Asian pitchers more unfairly than they did white pitchers. It’s a significant disadvantage for Asian pitchers because the MLB doesn’t have any Asian umpires. Interestingly enough, Hamermesh’s research found that the race of the batter didn’t seem to matter — the correlation was only between the pitcher and the home-plate ump. Rich Levin, an MLB spokesman, refused to comment on the research findings.

I don’t have much time to write much, but here is my quick take. This is an interesting study, which I had a chance to see a few weeks ago. When a similar study was done in the NBA, I immediately thought that baseball would be a better testing ground for this type of behavior. I had actually begun collecting some data when this study rolled across my desk. The most interesting aspect of this study is that the discrimination that exists shrinks in QuesTec ballparks, when umpires are being monitored.

The good news is that the effect of the bias is very small, a little less than one pitch per game. And I don’t think there is much that can be done to alter this (except more QuesTec), as it is probably the result of something deeply rooted in the human psyche. I don’t believe that umpires set out to make calls along racial lines, it just happens.

Kudos to Rich Levin for not pulling a David Stern and having a conniption. This is research of an interesting question, and I hope that the league work with the authors as opposed to castigating them. This should generate some good discussion. If you wish to comment—and I encourage you to do so—please behave yourself with such a sensitive issue.

Addendum: Here are links to the paper and FAQ.

13 Responses “Does Race Influence Umpires?”

  1. Larry Seltzer says:

    In the NBA study did the ouside controlled factors include the spread?

  2. Adam says:

    Could there be other factors? What about controlling for racial characteristics of the city where the game is being played (crowd factors). What about overall trends? Times of the year? In game characteristics? Are the sample sizes for minority umpires big enough?

    Basically, is this study publicly available?

  3. JC says:

    I added a link to the study in the post.

  4. S. A. Polinski says:

    If there is no racial bias evident between umpires and hitters, isnt it possible (especially since the difference is only a pitch per game) that the difference is due to pitchers throwing style or release point? Imagine the difference as an umpire of pitches coming out of the hand of Greg Maddux, Dontrelle Willis, or Diasuke Matsuzaka. i think it would be very interesting to see a comparison of submarine throwers to straight overhand, or “power pitchers” to “finesse pitchers”.

  5. Phil Steinmeyer says:

    MLB should roll out QuesTec in all stadiums as soon as possible.

  6. Marc Schneider says:

    Not being a statistician, it’s difficult to comment, but it seems to me that the guy has taken a relatively small correlation and projected causation (ie, bias). It seems to me that most social scientists would be more cautious about making such a definitive conclusion. And is the effect even significant? Apparently, it’s one or two pitches a game–that’s not likely to effect the outcome unless they are all in critical situations.

    Basically, from what I know of evolutionary psychology, humans are hard wired to favor others in their racial or communal group which would suggest that there is probably some bias in all of us (and common observation would agree.) But, in this case, if the bias is so unconscious and the effect so small, I don’t see much purpose to it. You could just as easily spin it the opposite way–that despite human predililection for bias, the study shows that there is very little in baseball.

  7. sean says:

    i imagine that 1-2 pitches a game is statistically significant, since the sample size was along the lines of n = 2.1 million.

    and, if the post is correct, claiming evidence of bias is a little different than simply attributing causation, but you’re right in that no respectable social scientist would takea single study like this one and claim anything totally definitive

  8. Parish says:

    I think Marc makes good comments.

    I am a statistician and when I reached the “effect of the bias is very small” comment I rolled my eyes. A little less than a pitch a game is less than a 1% sway and cannot accurately be described as bias. The number of pitches observed in the study may reduce the margin of error below 1%, but the number of pitchers observed is not even close. A single pitcher, bad or good, out of maybe 500-600 observed over a three year time frame can create this small of an aberration. The fact that much more than half of the umpires and pitchers are white would locate most of this alleged bias between the two.

    In my opinion, the researchers are misinterpreting the results of their study. There is, in fact, no bias.

  9. Ron says:

    Wouldn’t you want to also look at safe/out calls on the bases and ejections?

  10. Heather says:

    After seeing this paper, I’m starting to like QuesTec more and more. Notice that the people who complain most loudly about QuesTec are umpires (Ever met a man who wants more performance evaluation of his own job?) and veteran, superstar pitchers like Glavine and Curt Schilling, who are used to getting a larger-than-average strike zone. You’ll never hear a rookie like Joey Devine or Martin Prado complain about QuesTec. That’s pretty good evidence that QuesTec promotes fairness.

  11. Rick says:

    Doesn’t this “bias” also fall well within the error rate that Questec has detected. How could there not be any bias against hitters? This study really doesn’t make sense without bias towards them as well.
    You can find some articles on Questec and the strike zone over here

  12. Gordon says:

    “The good news is that the effect of the bias is very small, a little less than one pitch per game.”

    The authors say “less than one pitch per game,” but unless I’m misreading the paper the effect is more like one pitch every FIVE games. They conclude the called strike rate is .0034% higher when pitcher and umpire are same race. About one-half of pitches are called by the ump, so that means about one-quarter of a pitch per game. And comparing 100% to 0% same-race overstates the real effect, since no racial group of pitchers is at either extreme. Add it all up, and a white starting pitcher gains an advantage of perhaps half a run over an entire season.

  13. Phil Steinmeyer says:

    In the data section of the paper, on page 24, you’ll note that there only 93 umpires included, and only 8 of those are non-white (3 Hispanic, 5 black). That seems like a rather small sample set, although admittedly, the number of pitches judged is quite high.