Thursday, March 11, 2021

Leverage and the 1959 White Sox

They won the pennant and it seems like they did it partly on the strength of their performance in High Leverage situations because their overall OPS differential was not that impressive (all data from Baseball Reference and Stathead).

 Rk Tm W L W-L% OPS OPSA OPS Diff 1 CHW 94 60 0.610 0.691 0.671 0.020 2 CLE 89 65 0.578 0.729 0.693 0.036 3 NYY 79 75 0.513 0.721 0.680 0.041 4 DET 76 78 0.494 0.735 0.721 0.014 5 BOS 75 79 0.487 0.721 0.738 -0.017 6 BAL 74 80 0.481 0.655 0.678 -0.023 7 KCA 66 88 0.429 0.716 0.761 -0.045 8 WSH 63 91 0.409 0.688 0.711 -0.023

They had only the third highest OPS differential yet finished 5 games ahead of the Indians. Here is what the Sox did by Leverage:

 Situation OPS OPSA OPS Diff High Leverage 0.763 0.623 0.140 Medium Leverage 0.641 0.689 -0.048 Low Leverage 0.702 0.681 0.021

Here is how many PAs they had in each case, both for and against:

 Situation PA OPA High Leverage 1320 1370 Medium Leverage 2298 2305 Low Leverage 2437 2343

Given these numbers, if you combine the Medium and Low cases, they would have a negative OPS differential.

How much difference might this performance in High Leverage situations mattered?

Here is a regression generated equation where team winning pct was a function of overall OPS differential that I have found.

Pct = .5 + 1.32*OPSDIFF

This predicts the Sox would have a .526 winning pct and win 81 games. It predicts that Cleveland would win 84.

But another regression equation, broken down by leverage is

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

That predicts that they would have a .565 winning pct and win 87 games, six more than before (although still 7 less than what they actually won). The same analysis for the Indians would give them 87.9 wins.

What accounts for the Sox winning the pennant? Maybe the three leverage categories are not refined enough, with maybe the Sox doing even better in more extreme leverage cases. But that might not be easily found.

One thing I did find was that in head-to-head games, the Sox had a much better OPS differential in High leverage cases than the Indians than in Low and Medium cases. I will discuss that below

But first, the Sox went 15-7 against the Indians, going 5-2 in their 1-run games (overall, the Sox were 35-15 in 1-run games). So outside of head-to-head games, the Indians were 82-50 while the Sox were 79-53 (also, if the Indians had gone 5-2 in those 1-run games they would have won the pennant by one game).

The Sox had an overall OPS differential of .020 but against the Indians it was .077 (.710 - .633). Their OPS differential against everyone else combined was about .011.

The Indians OPS differential was .036 overall but against everyone else it was about .054 combined. So we could say that the Indians were .043 better than the Sox (.054 - .011).

That means in their head-to-head games there was a swing of .120 (.077 + .043). It looks like the Sox won the pennant because they did unusually well against their main competition.

And they were even better when it really counted. This table shows how each team did in OPS by leverage in their games against each other (data from Stathead).

 Split Sox Indians Sox Differential Low 0.676 0.584 0.092 Medium 0.689 0.674 0.015 High 0.819 0.630 0.189

That .189 differential in High leverage situations is close to the OPS differential of the 1927 Yankees (.196 according to Retrosheet, .200 according to Baseball Reference). Sure, that is the Yanks differential for the whole season, but by being close to it in High leverage situations, the Sox may have given themselves the pennant.

In late August, the Sox went into Cleveland with a 1.5 game lead and swept a 4 game series. The closest the Indians got after that was 3.5 games when in late in September the Sox came to Cleveland for one game (the Sox had 4 games left including that one and the Indians 5). The Sox won 4-2.

So just like with their performance in High leverage situations, the Sox won what might be considered the High leverage games late in the season.

Update March 12. Below is something from a post I did in 2009.

Let's look at how they did in "clutch" situations vs. other situations. The table below shows how the Sox hitters did in various situations.

Now what the Sox pitchers did.

Now the differentials followed by some discussion.

The total line, of course, refers to all plate appearances. The Sox had modest differentials here. They batted .250 while the Sox pitchers held their opponents to a .242 AVG. With no runners on base, the differentials are even lower. But now look at their differentials with men on. For AVG, it is .013, much higher than the .005 with none on. For OBP, the differential jumps from .009 to .023. SLG goes from .001 to .010.

With runners in scoring position (RISP), they had a .040 differential in AVG!. It was actually negative in nonRISP situations. Sox pitchers held opposing batters to a .221 AVG with RISP. Their OBP differential jumped from .007 to .040 while SLG jumped from -.014 to .063. Incredible. Their hitters' SLG went up .032 with RISP while the pitchers lowered it by .044.

Moving to close and late situations, the Sox outhit their opponents by .024 while it it was only .005 in nonCL situations. The OBP differential rose from .010 to .043 while for SLG it went from -.012 to .076. Another stunning swing. The Sox hitters actually had an SLG of .400 in close and late situations, by far their highest for any case.

So it is pretty easy to see what happened that year. I have not looked at other teams, but the case of the 1959 White Sox must be very unusual.