An ingenious FiveThirtyEight article by Michael Lopez, Brian Mills, and Gus Wezerek tries to show that "Everyone Wants To Go Home During Extra Innings — Maybe Even The Umps." They find that in extra innings major league umpires, probably unwittingly, change their patterns of ball and strike calls in ways that tend to end the game quickly.
The authors analyzed a sample of roughly 32,000 pitches thrown between 2008 and 2016. They obtained data using Bill Petti’s baseballr package, scraping pitch locations from Baseballsavant.mlb.com.
I love the fact that they undertook this work, and their nifty data graphic, but I wish it were clearer what question each result answers.
At one point the main question is presented as a) How much umpires tend to favor calls that would hasten an ending, comparing certain extra-inning scenarios vs. ordinary scenarios.
At another point it's stated as b) Strike rates in certain extra-inning scenarios for "teams that are in a position to win vs. teams that look like they’re about to lose."
A third and more complex comparison is implied by c), How umps "changed their behavior in these situations between 2008 and 2016," but I doubt this is what the authors intended to say.
Comments to the article abound, but until we know for sure what each finding means....Finally, not that statistical significance is the be-all and end-all, but it wouldn't have hurt to run a significance test or two, to let us know just how unusual the differences cited would be if one supposes they occurred by chance.
Roland B. Stark