February 16, 2008
Steps From Fenway, a Statistician Takes a Swing at the Yankees
Boston — This year’s AAAS meeting is taking place a stone’s throw from Fenway Park, home of last fall’s World Series champions, the Boston Red Sox. So it was fitting that mathematicians presented here new uses of statistics to study the game. And maybe it wasn’t surprising that the results contained unflattering news for the Sox’s archrivals, the New York Yankees.
Shane T. Jensen, an assistant professor at the University of Pennsylvania’s Wharton School, described how he and two collaborators set about to build an improved measure of fielding performance by major leaguers. Baseball statisticians have historically focused mostly on players’ hitting and on pitching, but fielding has been little studied systematically. (A widely cited stat, fielding percentage, measures fielders’ dropped balls. But because these are rare, it is considered a crude gauge.)
Mr. Jensen and two collaborators started by obtaining a newly available, detailed dataset that pinpointed where hits landed on the field during three seasons, 2002 to 2005. Mr. Jensen used these data to develop “probability curves,” showing how well each fielder at a given position chased down balls. He employed the curves to compare the fielding of all major leaguers at that position. He further tweaked the model (dubbed the Spatial Aggregate Fielding Evaluation, or SAFE) to show how many runs each fielder robbed from, or gave up to, opponents over an entire season.
One surprising finding: Alex Rodriguez, the Yankees’ star third baseman, actually was the second-best shortstop in the majors when he played that position for the Texas Rangers, before they traded him to the Yankees in 2004. The Bronx Bombers then assigned him to third base because they didn’t want to move their star shortstop, Derek Jeter. But Mr. Jeter, according to Mr. Jensen’s number-crunching, was actually the worst in the majors at that position.
On balance, Mr. Jeter has earned his pinstripes as a Yankee star because his batting prowess helps him score more runs for the Yankees than his underwhelming fielding gives up to opponents. However, Mr. Jensen said, some teams might find that they’d win more games if they invested more selectively in great fielders instead of sluggers, who are usually paid more.
Of course, statisticians stay awake at night thinking how to eliminate bias in their numbers, so, just to make sure all bases were covered, we asked Mr. Jensen to name his favorite team. He revealed without hestitaion that it was indeed the Red Sox. But, he added with a smile, “My co-authors are Yankees fans, so I think we’re fair and balanced.”
As further evidence of that, Mr. Jensen pointed out that his model ranked Manny Ramirez, one of the Sox’s top sluggers, as the second-worst left-fielder. Hey, there’s always next year — spring training begins later this month. Until then, Mr. Ramirez will have to console himself with his two World Series rings.
Jeffrey Brainard | Posted on Saturday February 16, 2008 | PermalinkComments
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Any baseball study that does not begin, “The Cubs are the greatest, therefore …,” is bogus and worthless. You’d think the AAAS would know that.
— S. Britchky Feb 17, 02:04 PM #
This is where the analysis of complicated data sets and a simple fan’s observation converge. Listening to Yankee games the phrase “hit past a diving Jeter” will be heard over and over ….
— Michael Feb 17, 02:29 PM #
Must be the four world series rings that weigh down the poor guy (i.e. what arrant nonsense!).
— Dennis Feb 18, 04:10 PM #
Finally after about 90 years they win a couple of World Series and they start thinking they’re good. And now a couple of guys with slide rulers want to provide them with “evidence”. Try winning 26 World Series!
— L. Perez Feb 18, 09:27 PM #
Red Sox & Yankee nation:
You only do well because of your money.
Give the Pirates or Devil Rays your money and they’d do well too!
Bubba (Go Braves!)
— Good ol' Bubba Feb 19, 08:45 AM #