Calculating Umpires’ Stats, Home Plate Edition

If there’s one thing baseball fans can agree on this postseason, it’s that the officiating has been below par. From calls getting blown down the line, on the bases, and over the plate – just about everywhere a call can be blown, really – the umpires have made a number of high-profile mistakes in these first two rounds. Some of these mistakes have been more damaging than others, of course, in terms of their impact on the final score, but that does not make any of them any more forgivable. For those of us who expect to see the best teams and best umpires working in October, it has been disheartening to say the least.

With each bad call, the umps have invited more and more scrutiny upon themselves: Who are the guys making the calls? How did they get chosen? Now that they’re on the biggest stage, are they making the right calls? These are questions that we just can’t get out of our heads. We baseball fans are a demanding bunch and when we fixate on an issue, we’ll dig deep in an effort to understand and analyze it.

Which brings me to this post: there’s been a lot of talk, especially in the past week, about looking at umpires’ performance through their stats. Or, more accurately, through the stats the players on the field put up while that particular umpire is working. With all of the information available at our fingtertips in this day and age, it’s almost surprising that we can’t break down an umpire’s performance on an individual basis. So I set out to change that this weekend. This is a huge problem to take-on, however, so it’ll have to be done in stages. My first step was to look at the stats of the current home plate umpires.

(View the Home Plate Umpire dataDownload the Home Plate Umpire data.
Click “Read More” to continue reading.)

Using the current Retrosheet database (which still only goes through the 2008 season), I found all umpires who worked the plate 10 or more times last year. I then went through the database and gathered all relevant stats from the games the each umpire worked behind the plate between the years of 1998 and 2008. These are the “Umpires’ Stats“. Why did I only go back 11 years? Well, besides the fact that I didn’t want to wait three weeks for all 55 years of Retrosheet data to be calculated, I wanted to make sure that the data were showing modern umpire tendencies. With MLB’s expansion to 30 teams in ’98, the increased offense, the bandbox stadiums, the tight strike-zone, QuesTech, and the umpire strike of 1999 (which resulted in 22 umps getting canned), among others, a lot has happened in the last 10 or 12 years to affect the way umpires call games. It seemed to make sense, then, to focus only on those years.

With the “umpires’ stats” calculated, we could now take a look at an individual umpire to see how many plate appearances he umped per game, or how many balls and strikes he called per plate appearance. Without more information, though, we wouldn’t be able to do much with it. How could we know, for example, that Umpire X’s tendency to rack up a lot of strikeouts per nine innings was a result of a wide strikezone and not merely because he was behind the plate for too many Tim Lincecum and Justin Verlander starts? Without knowing the performance of the pitchers that Umpire X saw in games that someone else was behind the plate, there are very few conclusions that we can draw. So I went ahead and made those calculations. For every pitcher that a particular ump called in a given year, I went through the database and gathered all relevant stats from the games in which the pitcher pitched in and in which Umpire X was not behind the plate. These are the “Pitchers’ Stats.”

I invite everyone to take a peak at these stats, or download them for yourself. I’m not the most sophisticated statistician – I have no doubt that there’s a lot more that can be done with this data than I’m doing here. If you have the means, I hope you do just that. I just thought it’d be nice to give everyone the data to work with. (View the Home Plate Umpire data. Download the Home Plate Umpire data.)

Here’s a sample of the data. Like I said, I’m confident others can figure out better ways to look at this, but this is what I can show you right now.

MLB announced their six-man crew for the World Series late last week. Here’s the data from 1998 through 2008 for each of those six umpires’ time behind the plate, compared to the pitchers’ stats from that time:

[[This table screwed up the formatting much more than I realized (in Firefox, at least… it’s manageable in IE and Chrome), so I’m removing it. You can see the World Series umpires stats comparison here. Sorry for that. I wish there was a better way for me to display bigger tables.]]

There’s a lot of information there, I know. But take a few minutes to compare some of these umps’ stats. Joe West, for example, gets much fewer strikeouts per nine innings from his pitchers than they normally throw (6.46 vs 6.84), while Brian Gorman gets nearly identical stats all the way across the board (K/9, BB/9, AVG, OBP, SLG, ERA). What strikes me most about this is how consistent the average number of balls and strikes per plate appearance are, as well as the average number of called, swinging, and foul strikes are. The biggest discrepancy in those columns belongs to Gerry Davis, who sees 0.58 called strikes per PA while his pitchers are used to seeing 0.62 called strikes. It’s not big, but it’s the best we have. It might be something worth watching during the World Series.

I’m going to leave it there for now. If you’re interested in downloading the data for your personal use, please feel free to. I’ll be playing around with all the data on my own, but I’m still anxious to learn what others might find. I want to gather this same kind of data for umpires at each of the other bases, but I’m a little uncertain on what data I should collect (balls/PA doesn’t mean much for the second-base ump, you know). If you have any thoughts on that – or on the data I have been able to gather – I’d be happy to hear them. You can always leave a message on this post or email me at This is merely a first attempt, after all. There’s bound to be ways to improve it. Thanks, and happy sabering!

Larry Granillo

About Larry Granillo

Larry Granillo has been writing Wezen Ball since 2008 and has dealt with such touchy topics as Charlie Brown's baseball stats and Ferris Bueller's day off. In 2010, he got the bright idea to time every home run trot in baseball; he has been missing ever since.