The Baseball Graphs Blog
Thursday, December 09, 2004
Shortstops and Defensive Win Shares
The outstanding Blue Jays’ blog, battersbox.ca, has a nice review of shortstops by Mike Green. Mike and the pursuant commentators do a particularly good job of discussing the measurement of a shortstop’s fielding impact.
Bill James put boundaries on fielding Win Shares, at both the team and individual player, because he didn’t fully trust the output (I think). This makes it hard to use fielding Win Shares to evaluate really good (and bad) fielders in any given year or career. This is a significant issue that should be kept in mind when discussing some of the great ones, like Ozzie Smith.
Thursday, December 02, 2004
Win Shares Replacement Level
Last year, we spent some time developing a baseline Win Shares level for each player, and we implemented the methodology at the Hardball Times during the year. This baseline is equal to the number of Win Shares an average player would achieve, given that specific player’s playing time. This then led to “Win Shares Above Average,” an important way to interpret Win Share totals.
At the time, I felt this was an important step toward establishing replacement levels for individual players, and I sort of made a promise to myself that I would tackle the issue when I felt ready. See, replacement level is a very complex issue with no right or wrong solution; Bill James admitted as much in his Win Shares book. I believe his next version of Win Shares will include the concept of “Loss Shares,” which is different from Replacement Level, though it also provides important context to Win Share totals.
Now, I’m not claiming that I all of a sudden have great insight into this replacement level thing. But I do now have two years’ data to play with—enough to take a meaningful stab. So I’ve decided to go for it.Click for more...
Wednesday, December 01, 2004
JC, who runs the Sabernomics blog, recently attended an economics conference that included, among other things, presentations of baseball economics. One paper in particular, An Economic Evaluation of the Moneyball Hypothesis, is fascinating for two reasons:
First, the authors set out to prove that major league teams truly did undervalue OBP before the publication of Moneyball—and they make their case very well. But to take it a step further, they also show that the baseball “market” subsequently valued OBP correctly after Moneyball’s publication—proving that General Managers really did read and learn from the book (despite the widespread disdain shown toward it).
Second, they used Win Expectancy/PGP analyses of the 1999 and 2000 seasons to prove a number of things that have been discussed before. For instance, they show that OBP really should be valued twice as highly as SLG. And they developed their own set of Linear Win Weights for each event on the baseball field (closely following a set already developed by Tangotiger).
This is geeky stuff, but the article is very readable, and I highly recommend it to my fellow baseball geeks.