We use Pythagorean Record to determine if a baseball team (or any team, really) is underperforming or overperforming. Runs scored and runs against tend to be truer predictors of a team’s actual quality than their win-loss record, and over time a team’s record tends to reflect their run differential.
Pythagorean record is generally a good predictor, and under normal circumstances this would not bode well for the Milwaukee Brewers. They have currently outscored their opponents 534-498 (+36) and their Pythagorean record sits at 64-57. They’re actually 70-51 and they’ve played about 6 wins better than you would expect.
The Cardinals, on the other hand, have outscored their opponents 574-521 (+53) and have a 66-55 Pythagorean record, and a 65-56 actual. That’s about right.
At some point, some smarty-pants may say to you “Look good sir, your Brewers may be flying high right now, but I have spent many a fortnight studying the intricacies of our various Pythagorean records, and I say to you verily that your arrogant but whimsical group of brewmeisters are in for some serious comeuppance.”*
So what’s wrong with this assertion? That would be Interleague Play.
The NL Central was lucky enough to face the best division in baseball in form of the AL East (which to some extent is only fair because the NL Central also gets to face the Astros and Cubs a bunch of times), and since you can’t play every team in a division during interleague play, some unfair imbalances always show up.
The Cardinals played 3 road games each against the Baltimore Orioles (46-72) and the Tampa Bay Rays (64-55). While that was going on, the Brewers played two 3-game road series against the two best teams in baseball; the New York Yankees (72-46) and the Boston Red Sox (73-46). The Cards struggled against the Rays losing the Series 2-1, but swept the pathetic Orioles, outscoring them 20-9. They’re overall RS-RA in these two series was 29-25. The Brewers, taking on Baseball’s juggernauts managed to eke out one win against Boston, but in every other game they were absolutely slaughtered. Their RS-RA in these two series was 15-46. While the Cardinals outscored their two opponents by 4, the Brewers were outscored by 31.
If you remove these games from the Cards and Brewers schedules and recalculate their Pythagorean records, things start to make more sense. The Cards are still 66-55, but the Brewers jump up to 68-51, much more in-line with their actual performance.
You are probably already thinking that it’s unfair to remove a game just because it was especially bad, and normally that’s true, but in this case I think it’s pretty defensible. Interleague play is a strange business. It creates unequal schedules, and it’s not as if the Brewers (or the Cardinals) face any of those teams again. The fact is that the Brewers were so manhandled by the big boys from the East that they managed to cram several extra losses into their run differential, but it was only a one-time thing.
10% of the total runs scored against the Brewers so far this season were scored against them in their 6 road games against the AL East. This was very significant. Cherrypicking and outright ignoring data is almost always a bad idea, but remember that this stat is supposed to be predictive. Interleague games in no way reflect what will happen down the stretch, and I would argue that how each team has played against the rest of the NL is going to be much more illuminating than some huge outlier created by a funky schedule.
*This is, of course, a Cardinals fan using the most respectful tone possible, and in no way besmirching the game. You should back away slowly and not make eye contact, and as you inch closer to the door you should mention that this assertion lacks context and is deeply flawed.
Then you should break into a full out sprint before he throws a baseball at you.