Kin
New member
Frank E said:http://www.fangraphs.com/library/principles/expected-wins-and-losses/
From the same article:
Regardless, what we need to know for now is that there?s both an empirical and logical relationship between runs scored, runs allowed, and wins, and they agree down to some very small details.
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A team with an expected winning percentage of .500 and an actual record of 77-85 is not ?really? an 81-win team, although it is true that deviations from pythagorean win-loss are subject to regression.[Nik's emphasis]
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If you shouldn?t use pythagorean expectancy to guess at team talent, and you probably shouldn?t refine it to more accurately ?retro-predict? actual wins, what exactly is the point of learning about it?
The quick answer is that you can use it to predict wins given expected runs scored and against, perhaps in a projection system.
Which was all that was being done. I said that regression to something more in line with their pythagorean W-L was a factor in their second half record.