Carleton: The effects of the shutdown innings

From Russell Carleton at Baseball Prospectus on October 21, 2013:

In the month of October, we’ve been hearing a lot of talk about shutdowns. No, not the debt ceiling thingy. The one that really matters: the shutdown inning. It’s playoff time, during which we often confuse something that players routinely do for an amazing feat of bravery and virtue. This postseason, everyone’s all a-twitter with thoughts of “shutdown innings.” For a pitcher, it’s the half-inning after your team scores (according to some people, it has to be scoring that leads to your team tying the game or taking the lead). Your job, in this most sacred of innings, is to keep the other team from scoring. It’s totally okay to give up runs if your team didn’t score last inning, apparently. Suddenly, that other shutdown seems downright logical.

I get the idea that people are going for. It’s a cousin of the “momentum” argument. By scoring in the last half-inning, one team has “grabbed the momentum.” A shutdown inning is the equivalent of yelling “no backsies!” It’s kind of a sneaky way to argue the existence of momentum within a game, without using the word. After all, who could argue against a pitcher allowing zero runs in an inning? The problem is that there’s a hidden assumption that a “shutdown” inning is more than just a scoreless inning. It is, in some way, more difficult than other innings, and if it is accomplished it adds something extra beyond the fact that the other team didn’t score. And if a pitcher does allow a run, he is somehow a moral failure for ceding momentum back to the other team.

I think the #GoryMath signal just went up.

Warning! Gory Mathematical Details Ahead!
Let’s first define a potential “shutdown” situation. From 1993-2012, I found all situations in which a team had scored in the previous inning and in doing so, had either taken the lead or tied the game. (We will refer to this as the “strict” definition of a shutdown.) I looked at what happened in the following half-inning, when that team took the field. For the purposes of simplicity, I looked only at situations where the starting pitcher was still on the mound.

I scored the inning as a shutdown if the pitcher recorded all three outs and gave up no runs. (Easy enough.) He got a non-shutdown if a run scored on his watch, even if he didn’t get through the inning. He got an incomplete (missing data) if no runs scored on his watch, but he was removed from the game before recording three outs. I used the same basic criteria to code all innings, whether shutdown situations or not, as scoreless or not.

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Originally published: October 21, 2013. Last Updated: October 21, 2013.