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Friday, September 21, 2007
LEV v LI
Joe Sheehan’s turn to talk about Ned Yost, and echoes what has already been said. (If you want to talk about Ned Yost, go to that thread.) But, that’s not why I’m here. He talks about the “Leverage score” (LEV), and refers to this for Brewers. The correct Leverage Index (LI) are here. LEV is not LI, and no one should confuse the two, nor think that each has some advantage over the other. They don’t. LEV should not be used to discuss leverage of situations as Joe Sheehan is doing. Ever. This was discussed in…
...part 2 of a 3-part series. As readers of this blog knows, at the risk of sounding like Homer Simpson, I have double-dared anyone at BP to justify their Leverage scores over mine. I’ll let you know if a brave soul over there will take me on. I’m always very cordial with all the gang (Dan, Will, Nate, Joe)there when I deal with them one-on-one. But, right is right. The more I see LEV used over there, the more I’m upping the ante.
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An interlude if I may on quality checking:
The BP list that Joe pointed to has a bug in it (which I did report to them… I may have sounded like a jerk up there, but I’m an honest one), whereby the “IP” totals is their seasonal IP, not their relief IP, but their LEV is their relief LEV. Dave Bush has 3 relief innings, and 170 starter innings. Fangraphs has his LI as starter and relief as 0.96, 3.15. BP has his LEV as 5.22.
A second problem is a LEV of 5.22. In Table 2-2.4 of BBTN, the highest possible LEV score is 4.21 (tie game, 2 outs, bases empty). No reasonable person would ever conclude that this situation is the highest possible leverage, so why keep saying that it is? Anyway, how can Bush have a LEV of 5.22, if the highest possible LEV is 4.21?
The BP list seems to have a minimum starter+relief IP qualifier (Aquino is not in the list), which is confusing to have Bush there, but not Aquino. And showing Sheets at all is triply-confusing.
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Back to the comparison. Scott Linebrink has an LI of 1.40 according to Fangraphs (which uses my data), but an LI of 1.08 according to BP’s LEV. Fangraphs has Matt Wise at 0.77, but BP has him at 0.96. The biggest gap is with Manuel Parra: LI of 0.61 and LEV of 1.20. So, LI thinks that Parra has been used in low-leverage situations mostly, while LEV thinks that when he’s been used, it’s been in more critical situations than Scott Linebrink. I’ll do the analysis if someone wants to argue that they believe that BP has it right (just don’t play Devil’s Advocate).