JC Bradbury – of Sabernomics fame and the author of forthcoming book The Baseball Economist – noted in an interview with Baseball Digest Daily that he was a fan of DIPS. For those who have not heard of this, DIPS is a metric used to evaluate the productivity of a pitcher in baseball. Voros McCracken invented this measure, which he explained in a Baseball Prospectus article in 2001.
In the course of explaining his measure, McCracken made the following observation about pitchers.
“There is little correlation between what a pitcher does one year in the stat (hits per balls in play) and what he will do the next. In other words, what Eric Milton’s hits per balls in play was in 2000 tells us next to nothing about what it will be in 2001. This is not true in the other significant stats (walks, strikeouts, home runs). Walks and strikeouts correlate very well and homers correlate somewhat well.”
“This is a crucial fact. One of the more critical aspects of statistical analysis is determining how well a statistic reflects an ability. It’s the test given to clutch hitting, catcher game-calling, pitcher won/loss records, and so on. One of the first things asked when addressing this is “Does the stat correlate well with itself from year to year?” One reason clutch hitting is questioned is that the “clutch hitters” change from year to year, which indicates that it probably isn’t the hitter as much as it’s other factors. The answer to whether hits per balls in play correlates well from year to year is a fairly solid “no.””
Why are hits per balls in play not consistent across time for pitchers? It is because how many hits a pitcher allows depends upon the ability of the eight players surrounding the pitcher on defense. In other words, part of what is credited to pitchers is actually a reflection of his teammates.
The point McCracken makes about pitchers is quite similar to a point we have made about quarterbacks in football. As noted in The Wages of Wins, in a recent post to this forum, two weeks ago by Martin Schmidt in The New York Times, and this past weekend in my own New York Times Keeping Score column (okay, we told this story more than once), quarterbacks are quite inconsistent across time.
Why are quarterbacks so inconsistent, especially with respect to turnovers? Again the answer is that the statistics we credit to quarterbacks depend upon the actions of the quarterback’s teammates.
Here is the odd part of the story. In the sports of baseball and football, wins and losses are often credited to individual pitchers and quarterbacks. Basically, the two positions whose performance in their respective sports depends crucially on the actions of others, are given full credit – and blame – when their team is victorious – or not.
Given what we now know about the performances of these athletes, how long will it be before people stop evaluating these players in terms of wins and losses?
— DJ
Wages of Wins Journal 
disappointmentzone
September 12, 2006
The general public will never stop evaluating pitchers in terms of wins and losses. Quarterbacks, maybe.
Travis
September 12, 2006
Since pitchers and QB’s have the ball the most their performance probably has the most to do with the outcome of a game. And from a fan’s point of view assigning wins and losses to specific players, like QB’s and pitchers, makes it more fun.
Maybe a wins and losses should be attributed the owners. Since it’s the owners who decide who plays for a given organization and who doesn’t one could make the argument that they have the biggest impact on the outcome of a game.
Jason
September 12, 2006
Baseball has employed rate statistics for quite some time. While wins and losses for pitchers probably won’t go away anytime in the foreseeable future, at least in terms of what a pitcher commands on the market, I suspect that ERA, something he has more control over, is more important.
That said, many fans and, I suspect, some front office people believe that wins capture some of the “intangibles” and that guys who win have a tendency to do so independent of statistics that otherwise correlate with performance. While it’s likely that this is simply the result of the distribution of stochastic events, the popular perception is tough to shake. Bartolo Colon, last year’s AL Cy Young award winner was not as statistically dominant as Johan Santana, though Colon has 21 ‘wins’ to Santana’s 16. Colon gave up more runs but got better support from his bullpen and offense and, in essence, got lucky. It didn’t fool the Sabermetric folk, but it certainly fooled most of the writers who voted overwhelmingly for Colon as top pitcher in the league.
Kevin Pelton
September 13, 2006
“Why are hits per balls in play not consistent across time for pitchers? It is because how many hits a pitcher allows depends upon the ability of the eight players surrounding the pitcher on defense.”
I don’t think this is quite an accurate way to represent batting average on balls in play. If the defense was the main factor in season-to-season variation, we would expect players on the same team to have very similar BABIPs. This isn’t the case, however.
Look at the 2004 highest and lowest BAPBIPs. There are eight teams represented in the 10 lowest group, nine teams in the 10 highest. There are even two sets of teammates with one player posting one of the highest BABIPs and the other one of the lowest.
It seems to me the single biggest factor in the variability of BABIPs is randomness or small sample size.