Monday, June 14, 2010
FanGraphs: Angels are getting lucky
By Matthew Carruth, FanGraphs
Despite the generally accepted wisdom, a team’s win-loss record is not always the best measurement for how well it has been performing during a season, especially early on. Statisticians prefer to do whatever they can to increase the sample sizes of their measurements, and while each game yields just one win and loss, it involves roughly 75 plate appearances and hundreds of pitches. Therefore, a team’s record is more prone to fluctuation than its overall hitting and pitching stats are. Evaluating teams based on the more numerous plate appearances provides a more sound measure of a team’s performance to date.
One such method of evaluation along those lines is BaseRuns, which is a formula used to predict how many runs scored and allowed a team should incur based on the number of hits, walks, home runs, stolen bases and total bases. Those predicted run totals can then be put into another well-tested equation, called Pythagorean Record, to produce how may wins and losses a team should have based on those more stable predictors.
We can compare that predicted record to a team’s actual record to find out which teams have been especially lucky or unlucky. Three teams stick out from these results as being especially lucky, Pittsburgh being one. It probably is surprising to hear Pittsburgh regarded as lucky, given its 23-40 record, but consider that the Pirates' run differential is minus-140 runs, by far the worst in baseball. The Pirates should hold MLB’s worst overall record, but instead, they sit six games ahead of the Orioles. The Astros have similar benefits, having MLB’s third worst run differential but a record about six games better than expected. Trumping all teams, however, the Los Angeles Angels sit as baseball’s luckiest team by this measure.
It is not atypical to find the Angels considered a “lucky” team by analysts. Quite often, their difference in actual wins over predicted wins is chalked up to savvy baserunning, a reliable bullpen and steady guidance from manager Mike Scioscia. Skeptics of these write-offs have extra reason to scoff this season, as the Angels have been successful on just 40 of 61 stolen base attempts (66 percent) and their bullpen has a 4.79 ERA, which is third worst in the AL.
Projected over a full 162-game season, the Angels are on pace to win a whopping 16 more games than BaseRuns indicates they deserve. As it stands now, they are 36-30 and own a .545 winning percentage, which would be good for about 88 wins. Yet they've scored exactly as many runs as they’ve allowed, and based on their overall profile, BaseRuns says the Angels would be lucky to even be .500 and that their record should be 29-37, which would give them 72 wins over a full season. Angels fans might be flying high right now with their team’s recent success, but they would do well to exercise cautious optimism for the rest of 2010.
Matthew Carruth is a writer for FanGraphs.