Monday, October 29, 2018

Red Sox Excelled In High Leverage Situations This Year, Allowing Them To Win Seven More Games Than Expected Based On Their OPS Differential

Here is a regression generated equation where team winning pct was a function of overall OPS differential. It was based on the years 2010-14. All data from Baseball Reference's Play Index.

Pct = .5 + 1.3246*OPSDIFF

The Red Sox had a team OPS of .792 while allowing their opponents .698, for a differential of .094. The equation estimates they would have a .6245 winning pct. That would be 101 wins. But they actually won 108 games.  Maybe it was because they did so well in High Leverage situations.

Split OPS POPS Diff
High Lvrge 0.854 0.649 0.205
Medium Lvrge 0.801 0.734 0.067
Low Lvrge 0.762 0.689 0.073

They had a .854 OPS in High Leverage cases while allowing .649. Using the same years, here is the regression equation when breaking things down by leverage

Pct = .5 + .306*LOW +.420*MED + .564*HIGH

Where LOW, MED and HIGH are the OPS differentials in the three cases. That equation estimates they would have a .666 winning pct., good for 107.9 wins. So it looks like their High Leverage performance added about 7 wins.

In case anyone is curious, in LOW, MED and HIGH case for all of MLB this year, OPS was .724, .734, .724, respectively. So on average, teams do about the same in all cases. But the Red Sox were much different than that.


Anonymous said...

I'm still amazed that the Sox had 4 players in the top 15 for RE24.

All managers follow the book and play the percentages but I've never seen any manager so richly rewarded (or lucky?) as Cora was this year. Seems like he had the golden touch - every move he made produced runs.

I've seen several comments making the claim that this is the greatest Sox team ever.
We'll never know but I still like the 1915 team with the OF of Lewis, Speaker, Hooper and IF of Hoblitzell 1B, Wagner/Berry 2B, Everett SS, and Gardner 3B. Great positional players and their pitching was the best: Babe Ruth, Joe Woods, Dutch Leonard, Rube Foster, Ernie Shore, Ray Collins, closer Carl Mays, and a young Herb Pennock.

Cyril Morong said...

Those Red Sox won 4 World Series titles back in the 1910s. So pretty darn good. Thanks for reading

Alan D McIntire said...

I enjoyed your article.

If they were EXPECTED to win 101 games, since 101/162=.623,
the VARIANCE in wins would be Npq= 162*.623*.373= 37.645
The Standard Deviation would be the square root of variance, or 6.135 games.
Since a normal curve is continuous, and the number of wins is discreet, the z score of anything over 107.5 wins is the probability that Boston exceeds their 101 game expectancy.

Boston's z score would be (107.5-101)/6.135 = 6.5/6.135= 1.059

Going to this online program

and plugging in a z score of 1.059

I see that there was a 14.48% chance that Boston would exceed their win expectancy by over 7.5 games. It's luck, but not out of the ordinary luck.

Cyril Morong said...


Great analysis. Thanks.