Baseball Events != Isolated and Guaranteed

There are a few aspects of baseball broadcasting that really irk me, including the presentation of data for a player against a specific team in his career, batter-pitcher matchups being treated as gospel (especially with under 10 such occurrences), and definitive claims based on small sample sizes. I mean, does it matter that Jamie Moyer has an XXX ERA vs. the Milwaukee Brewers over his 400-year career, when there were dozens of different iterations of the Brewers lineup? Does Alfonso Soriano going 4-7 off of Doug Davis mean anything at all if the seven plate appearances are spread over five seasons? The one that bothers me the most, though, is the idea that every event in a baseball game is isolated, and therefore guaranteed to occur regardless of the preceding circumstances.

Consider this example: Jimmy Rollins on first, Ryan Howard up to bat. Rollins gets caught stealing, Howard hits a homer. The announcers are bound to say something like – “Well, if Rollins stayed put, the Phillies would have scored two on the Howard homer.” Fans do it all the time as well, buying into this idea that Rollins being caught seemingly had nothing to do with the subsequent pitch selection, location, or anything else along these lines.

Forgive me for going all Butterfly Effect, but Rollins being caught in this example changes everything. For starters, the pitcher is throwing out of the windup rather than the stretch. With nobody on, he might be able to concentrate more on the hitter. He may decide to throw a steady supply of heaters as opposed to breaking pitches. We could go on and on about the different types of strategy inherent when such a situation shifts, but the point is that the situation DOES shift. I don’t care if Howard has a better or worse chance of hitting a homer if Rollins does/does not get caught in this hypothetical because the point remains that the situation has changed. The plate appearance is not the same, and Howard is in no way, shape or form, guaranteed to hit the home run if Rollins was not caught on the bases.

The worst part is that this is not even a tough concept to grasp, yet it gets ignored by almost everyone. It is way too easy to fall into this trap, thinking that events are not tied together, but they are, and need to be treated as such. This isn’t like trying to get announcers to use wOBA instead of BA, but rather trying to get them to understand simple logic. Events in a game are not isolated. They might not be completely, 100 percent, dependent on surrounding circumstances but they are certainly not isolated and guaranteed to occur no matter what.

Eric is an accountant and statistical analyst from Philadelphia. He also covers the Phillies at Phillies Nation and can be found here on Twitter.

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14 years ago

I get your point, but I feel like the Rollins example isn’t a great one. When you have a speedy runner on first base, the pitcher will a) be pitching out of the stretch; b) have some part of his mind concentrating on holding the baserunner; c) probably throw more strikes to avoid having runners on 1st and 2nd; and d) throw fewer breaking balls. All of these things would seem to actually increase Howard’s chance of hitting a HR in your example. Meanwhile, stealing 2nd (even successfully) I would imagine lowers that chance, because now the pitcher won’t be so worried about giving up a walk and putting a slow baserunner on 1st.