From SABR member Sean Forman at NYTimes.com on August 20:
This season, the surprise team is the Arizona Diamondbacks, who at the start of play on Thursday held a two and a half game lead in the National League West over the defending champion San Francisco Giants. The Diamondbacks at 69-54 had already exceeded last year’s total of 65 wins. Last season’s surprise team, the Cincinnati Reds, has backslid from a 91-71 record to a 60-63 record this season.
It seems apparent that the Diamondbacks are playing at a higher level than the Reds, but a look at their pitching staffs and batting orders muddies the analysis. The Reds are second in the N.L. in runs per game at 4.68 with the Diamondbacks just behind them at 4.56. The Reds’ pitching and defense, which has been their Achilles’ heel this year, is 10th with 4.34 runs allowed per game, but the Diamondbacks are in 11th at 4.39. So if the Reds are scoring more runs and allowing fewer runs why are they nine games behind the Diamondbacks?
Bill James noticed similar cases while he was writing his landmark series of Baseball Abstracts. In response, he developed a runs-based win-loss estimator called Pythagorean Winning Percentage (pW-L%).
Read the full article here: http://bats.blogs.nytimes.com/2011/08/20/looking-past-mere-wins-and-losses/
Originally published: August 22, 2011. Last Updated: August 22, 2011.