The World Series Strike Zone’s Been Almost Perfectly Even

Yesterday I slapped together an InstaGraphs post about a Jon Lester strikeout of Brandon Guyer. It was a called strikeout on a pitch off the plate, but it was also a strikeout Lester has recorded several dozen times before. That part, I found interesting. But the call was also important in the moment. It changed the Indians’ odds of winning Game 5 by 10 percentage points, and during the game I tweeted that out with a screenshot. I didn’t expect the tweet to blow up like it did.

This isn’t supposed to be boastful. Wow, retweets, all right. Nobody cares. What happened as a consequence of that tweet going around was that countless different people started showing up in my mentions. And wouldn’t you know it, but those people had opinions about the strike zone! Some people were convinced the umpires were in the tank for the Cubs. Other people were convinced the Indians didn’t have any right to complain after calls they’d gotten earlier. More people still accused me of whining for some reason, as if a screenshot and a fact are opinions. The overall response was emotionally charged. Maybe not a surprise, in a World Series elimination game, but people were stirred the hell up.

Guess what! The zone’s been even. The Indians have gotten calls in their favor. The Cubs have also gotten calls in their favor. The World Series isn’t over yet, of course, but through the five games we’ve watched, neither team has really gotten a more favorable zone to pitch around.

As is usual, for this study I chose to trust the numbers pulled from Baseball Savant. I looked at every pitch so far called a ball or a strike, and in total they number more than 800. I assigned something like a rule-book strike-zone box, even though I know that’s not how the zone is actually called. I went hunting for incorrect calls — should-be balls called strikes, and should-be strikes called balls. I hunted in accordance with the rule that a strike needs for just any part of the baseball to touch the zone. A legitimate criticism: I’ve examined everything in two dimensions. The real zone is three-dimensional. I’ve done this for simplicity, and pitches just don’t move that much when they’re over the plate itself. That is a potential failing of this research, but it should be minor, and it shouldn’t favor either side.

As I went through the spreadsheet, I found 73 incorrect calls. That might seem like a lot in just five games, but it means the umpires made calls with 91% accuracy, which is pretty good. And, you know what, borderline calls are just hard to make. I designated the calls that favored the Cubs, and the calls that favored the Indians. Here’s a plot:

What you probably care about: Out of the 73 incorrect calls, I found 36 that favored the Cubs. It follows that I found 37 that favored the Indians, giving them an edge of all of one call through five full games. That’s negligible.

What happens, though, when you consider the situations? Good question! What if one of the teams was getting all of its calls in the most critical spots? For the 36 calls going for the Cubs, I found an average Leverage Index of 1.05, with a median of 0.92. For the 37 calls going for the Indians, I found an average Leverage Index of 1.01, with a median of 0.88. If there’s any difference in there at all, you can just say it cancels out the one extra call for Cleveland. Things have been balanced.

Most fresh in my own memory is the strikeout of Guyer. I didn’t love that call, and it was reasonably important. If you look at the plot above, you see a lot of the more extreme calls outside of the zone going to Chicago. That’s something, sure. But you’re still not talking about very much, and the incorrect call in the overall biggest spot favored Cleveland. When Guyer struck out, for example, the Leverage Index was 1.64. Somewhat high. The most important spot in my spreadsheet occurred in Game 3, with the Leverage Index at 5.40. Cody Allen pitched to Ben Zobrist in the bottom of the ninth, protecting a 1-0 lead. There was a runner on first and nobody out. Allen’s first pitch:

That pitch was called a strike. It was a good pitch! It was basically the pitch that Allen wanted to throw. But the pitch was off the plate. It’s off the plate in the screenshot, and it’s off the plate in the spreadsheet. By a few inches, in fact. I know we’re all accustomed to lefty strikes, but those have been gradually disappearing. And even though this was just the first pitch, as compared to the pitch to Guyer coming in a full count, we all know the first pitch is an important one. Allen this year allowed a .735 OPS after 1-and-0, and a .423 OPS after 0-and-1. Zobrist had a .946 OPS after 1-and-0, and a .703 OPS after 0-and-1. I don’t mean to just dwell on this. Again, overall, the zones have been even. But Zobrist subsequently struck out. The Indians won by a run. Each team has gotten its breaks.

Because the Series isn’t over, there’s still a chance for the final zone to favor someone. That’s going to come down to tonight and, possibly, tomorrow. But we’re here now because the zone has been balanced. Both teams have been hurt, and both teams have benefited. It’s easiest to remember the calls that go against the team you’re pulling for, but that doesn’t mean the other calls never happened. They’ve happened here in almost perfect harmony.