As we analyze the Yankees’ season, we often focus on the role luck plays in a baseball game. For those not used to the concept, though, it can be confusing. This isn’t the luck that leads you to find $10 in the washing machine, but it is more akin to the luck that leads you to just catch your train in the morning one second before the doors close. That still doesn’t answer the question what exactly luck is in a baseball context.
For that answer, we can turn to a three-year-old Wall Street Journal article by Russell Adams. In it, the author explores concepts and analysis surrounding luck. Using ample data points from the rich history of baseball, leading analysts both inside baseball’s front offices and outside of them can determine whether a player’s performance is lucky or a sign of a different shift.
Luck can take on a few different forms in baseball. On an individual level, the most obvious example is Batting Average on Balls in Play (BABIP). The average player’s BABIP will generally hover somewhere around .290. A player with a BABIP of .250 may be unlucky; he isn’t hitting them where they ain’t. He also may be popping up more and hitting fewer line drives, both negative factors on the ol’ BABIP. By looking at outcomes and results, statisticians can weed out bad luck from good.
On a team level, luck manifests itself in the form of win-loss records. Generally, history has shown that teams’ records track with their runs scored and runs allowed. This is known as the Pythagorean expectation. Teams that score a lot of runs without allowing as many generally win a lot of games, but one-run games or blowouts — the so-called “random” events — can impact the perception of how good or bad a team actually is. (For more on team-based luck, check out J.C. Bradbury’s take. He has written extensively on the topic.)
This year, the Yankees have, by one measure, been lucky. Based purely on their +60 run differential — they’ve scored 60 more runs than they’ve allowed — they should be 49-39 rather than 51-37. That calculation, however, doesn’t account for various factors, such as strength of schedule, Chien-Ming Wang‘s problems and the early-season blowouts. Another calculation, however, should give comfort to Yankee fans.
Using a complex statistic called base runs that attempts to calculate expected runs scored and expected runs allowed while controlling for strength of schedule, Matthew Carruth at FanGraphs has the luck breakdown of every team in the Majors. In this calculation — one Carruth admits is subjective, as are most complex concepts of team luck — the Yanks have a luck factor of -1 and the Red Sox are at 6. Tampa is at -9. In a perfect world, these would all balance to 0, and the AL would continue to be a three-way race between Tampa, New York and Boston.
(As an aside, a few FanGraphs commenters had some issues with Carruth’s methodology. Take a gander through the feedback there if you’re interested. My point will remain the same.)
So, where does this leave us? Well, as I said, we could take comfort in the luck factor. The Yanks were a bit unlucky and are still the Wild Card leader. Sounds good to me. But Tampa is a dark horse. If their luck evens out and Boston’s does as well, they could jump ahead of the Sox and Yanks in the standings.
In the end, then, we’re left where we started. We can understand the role luck plays in baseball; we can blame it for some of the Yanks’ failings; but we will be subjected to its whims this summer. As the 2009 season hits its second half, the two teams in the AL East who are the luckiest will probably be the ones playing in October while the third will go home.