For those that follow the debate around Michael Lewis’ Moneyball and its effect on front office strategy there is a fantastic article over at The Hardball Times. For the uninitiated, Moneyball follows Oakland A’s General Manager Billy Beane during the summer of 2002 as the team attempted to implement a different strategy to make his small market team competitive against the financial juggernauts of the league. The general idea: teams traditionally overpaid for and rewarded the wrong types of offensive skills by using the wrong kind of metrics to measure player value (e.g. Batting Average, Runs-Batted-In, etc). To become competitive with less resources, Beane and the A’s would instead focus on signing cheaper players with a more efficient and productive skill set.
Now, there is an entirely separate debate whether Beane and his approach actually work. Instead, the article focuses on whether publicizing Beane’s approach had a significant effect on the way GM’s built their teams. The basic hypothesis is that teams should place greater value on hitters with higher On-Base-Percentages than other, traditional offensive statistics, such as Home Runs (HR) and Runs-Batted-In (RBI). If the correlation between player compensation and OBP increased while correlations with traditional benchmark statistics decreased that would point to the potential influence of Lewis’ book on the game.
So what actually happened?
The year 1997 may be an outlier in this case, but the correlation between the two [salary and OBP] was .31 in that year. We see that in the late ’90s and early oh-ohs, the correlation danced between .40 and .50. In 2001, one year prior to Moneyball, it was at .44. By 2004, it was .64. The strength of the correlation (as measured by R-squared) about doubled. Coincidence? Maybe. But maybe, just maybe, the people who actually make the decisions in baseball actually read and accepted the conclusions in Moneyball.
Note that in the years before Moneyball, HR and RBI clearly drive the market much more clearly than does OBP. By 2004, the jump in OBP’s popularity had pulled it even, partly because HR and RBI fell in their correlative power. In 2005, OBP was actually the better correlate of salary. Chicks may dig the long ball, but apparently nerds were running the front office of your favorite MLB team. Look what happens after 2005 though. There’s a general downward trend for all three stats. It’s likely that OBP did have its day in the sun, but why would HR and RBI, so long dominant, also fall?
It is an interesting analysis. My skepticism lies in the fact that while we see some interesting correlations it is hard to parse causation out of this. It is clear that the market began to correct itself and alter how it values certain skills. But was this the direct result of Lewis’ book? Or was Lewis simply providing an anecdote representative of a larger, growing trend around baseball? There does seem to be a general trend upwards (if you smooth out the yearly volatility) in terms of salary and OBP even prior to 2002. (Of course, I would be curious to see the data set–are there a few powerful outliers driving the results? Were there a few, big market teams overspending on these types of players?) Also, a number of Beane acolytes went on to run their own ball clubs while the Red Sox hired a young, Moneyball-minded GM names Theo Epstein in 2002 as well as sabermetric godfather Bill James in 2003 (the two would build the team that would eventually win the World Series in 2004 and again in 2007). Likely it was a bit of both–an already growing trend within the game given additional validation and exposure via Lewis’ brilliant book.