Fein: Measuring the Accuracy of Baseball’s Win-Percentage Estimators

There are several formulas out there that can be used to estimate a team’s “real” record: Pythagorean Formula, Pythagenport, Pythagenpat, etc. Some use run differential and some use a run-to-runs-allowed ratio.

The question is: Which is the most accurate? The least?

Using the Lahman Database, I ran tests of 13 different methods on every team since 1921 (the end of the Dead-Ball era) to find the most accurate way to measure a team’s expected record, with 1981 and 1994 excluded for obvious reasons.

...What’s funny is that Clay Davenport, inventor of Pythagenport, denounced his method in favor of Pythagenpat, yet it is in reality the best method when compared to actual record.

Earnshaw Cook may have been the first to create a win-percentage estimator, and the Double Edge method created by Bill James was never actually used, so their finishing near last can both be forgiven.

The Kross method, on the other hand, cannot be, as it was supposedly a precise way to estimate winning percentage.

Thanks to Son of Samos.