One of the easiest ways to get a sabermetrician riled up is to tell him or her that so-and-so is the best hitter because he always gets it done in the clutch. People throw around the term “clutch hitter” for guys like David Ortiz and Derek Jeter, but the truth is, it’s awfully hard to prove that good performance in crucial situations is really the result of some innate “clutch” ability. It’s clear that there are clutch hits, but whether or not that’s a result of player ability or pure dumb luck is the matter in question. Most of the existing baseball research suggests that clutch hitting does exist for individual players, but at such a small level that it falls well below a standard range of error. In other words, it looks like it’s there, but there’s no way to tell.
You could call me a sabermetrician, and I would embrace that label. A significant part of my interest in sports involves understanding the way the game works beneath the surface, beyond the conventional wisdom. So, naturally, the clutch hitting debate is one of the baseball issues I always fall back on in my thoughts. When I combine that with an interest in win probability-based statistics (which have a distinct clutch component), I end up thinking about it a lot.
I probably won’t be answering anyone’s burning questions about clutch hitting with the small bit of analysis here, but I have been looking at an interesting wrinkle in the existing Clutch component of WPA:
When you look at WPA alongside its sister statistic, Leverage Index, you can theoretically remove some of the statistical “noise” of WPA and make it more meaningful. The idea is that WPA/LI gives you a better indicator of the part of a player’s performance that the player actually controls, regardless of the situation in which he is used. The end result is that you have WPA/LI, which is the leverage-neutral performance, total WPA, and what we have simply called Clutch – the difference between the two.
I’d like to suggest today that there’s more to this Clutch statistic than performance above or below what is expected in a given situation. Let me first show you a table of the Braves’ regular hitters this year, with WPA, WPA/LI, Clutch, and their per-plate-apperance rate stats. Hitters are a good study for this, since they have a small variation in pLI (Leverage Index per PA) compared to pitchers – the result of the manager not having much control over which hitters to use in crucial situations because he’s confined to a specific order.
Pete Orr is really the only player Bobby Cox has chosen to use only in less-crucial hitting situations, a conscious decision by the manager from the bench. Everyone else has basically been subject to where they are in the lineup, with a pLI between .9 and 1.1.
The problem with Clutch as an encompassing measure of clutch hitting is that it actually measures more than that. We know that the part of WPA that is influenced by the leverage of a situation can be factored out, and we get WPA/LI as a result. However, it’s also important to realize that Clutch, the resulting difference between WPA and WPA/LI is itself a product of Leverage Index.
Let me offer an example:
If Kelly Johnson always came to the plate when the LI was 1.19, as it was in the fifth inning of Saturday’s game, and he tripled in every at-bat (as he did then), his WPA would always be +.119, his WPA/LI would always be +.100, and his Clutch would always be +.019. This is not entirely the result of Kelly’s own “clutch ability,” though. To put it differently, if his “real ability” is +.100 in WPA/LI, you would actually expect him to get +.119 in WPA and +.019 in Clutch every time he came up to the plate, as long as the LI is 1.19.
It would seem reasonable, given that example, to conclude that a certain part of a player’s Clutch rating is to be expected, given his “real” WPA/LI performance and the leverage index at that juncture of the game. Clutch is, therefore, a function of both the player’s innate clutch ability (however large or small that may be) and the leverage he has faced.
Now, let me try to separate those two factors of Clutch. Seeing that Johnson’s pLI for the season is 0.91, we can “expect” a clutch rating of 9% (1.00-0.91) of his “real” WPA/LI performance below zero. Why below zero? If his pLI were exactly 1.00 in every plate appearance, his WPA/LI and WPA would be identical, therefore resulting in a zero clutch rating, regardless of his actual clutch ability. With a below-average pLI, he would have a negative expected clutch. In effect, because his plate appearances have come at less crucial times on average, his clutch rating has been penalized. Taking -9% of his WPA/LI out as “expected clutch” performance, we can then find his actual clutch performance. Let me present another table of the hitters below, this time with Expected Clutch (EC) and actual Clutch Performance (CP).
The last two columns represent the two pieces of Clutch: Expected Clutch and Clutch Performance. Notice that Kelly’s Clutch rating of +.245 is actually made up of -.112 of EC and +.356 in CP. Since he has had fewer than the normal amount of clutch PAs, his actual positive clutch performance is better than his Clutch rating. The opposite is true of Pete Orr, whose poor clutch performance has been masked somewhat by Bobby Cox’s relative unwillingness to use him in key situations.
Looking at the team totals for CP, Braves batters are +.667 for the season, while pitchers are +.687, for a total of about 2.7 wins above average in clutch performance alone. When you consider that the Braves are currently playing 3 games better than their Pythagorean expectation of 35 wins, that’s an interesting correlation. I don’t know if the two are related, but it seems like they could be. It makes more sense than saying they’re over 5 games above average based on Clutch.
Having explained all that, all of these numbers could be meaningless, because we don’t really know if the residual Clutch Performance/CP number is actually the result of the batter’s innate clutch skill or if it is simply luck. Research suggests it may be a little of both, so this doesn’t get us any closer to answering that Big Sabermetric Question. It’s all just part of the search to find meaning in these numbers where we didn’t know it existed. I’ll add CP and pCP (Clutch Performance per PA, kin to pWPA) to the tables that I post each week, and perhaps I can look at it in more detail in the future.