Data from the Baseball Reference Play Index and Retrosheet.
DIFF is the value of the coefficient on OPS differential in the regression. INT is the intercept. Std error is the standard error. Per 162 games is the standard error times 162.
It seems like the relationship has gotten slightly stronger over time if you look at the standard errors, although the DIFF coefficient does not seem to be as strong as it used to be.
Also, for some reason, before the 1960s, the intercept was below .500. You might expect a team with a .000 OPS differential to have a .500 record. But that was not the case for some time. Not sure why. Maybe greater imbalance in talent levels across teams (like those great Yankee teams) meant that if you were just "average" you lost alot more than you would expect when you played those top teams.
|Period||DIFF||INT||r squared||Std error||Per 162 Games|