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Tuesday, November 08, 2011
Who surprised Vegas?
Xeifrank has a great post on his blog. He converts all the game-by-game odds of Vegas into a win probability for each team (and tracked it by starting pitcher). Then, he simply compared how many games the team actually won to how many Vegas expected that team to win, with that pitcher.
For Felix Hernandez for example, Vegas had no surprise: the Mariners won exactly as many games as Vegas expected. The DBacks, with Kennedy on the mound, won alot more. Tigers/Verlander as well.
Basically, either it took time for Vegas to catch up to the change in the estimate in the true talent level of Kennedy, Verlander, etc, or, there was alot of good luck in the wins of Kennedy and Verlanders, etc.
How to tell? Well, compare the differences between actual and expected, and see if that matches to what you’d expect from random. If it’s an exact match, then we know that the differences were all luck. (i.e., expect Vegas to not change their estimate in true talent level for Kennedy, Verlander et al). If on the other hand the differences are wider than expected, then Vegas was a little slow in adjusting for the estimate in change in talent levels.
blogspot is blocked at the office, so I will rely on a Straight Arrow reader to help us out.