Thursday, March 12, 2009 | 2 a.m.
Pythagorean Winning Percentage
Popularized by author Bill James, Pythagorean winning percentage in baseball is a way to estimate a team’s likely record based on the number of runs it has scored and allowed. Fans or bettors might use it to determine which teams have been “lucky,” or playing over their heads; or “unlucky,” or underachieving vis-a-vis their win-loss record. The original formula for Pythagorean winning percentage (inspired by mathematics’ Pythagorean theorem) was: runs scored squared divided by the sum of runs scored squared and runs allowed squared. The traditional formula has been modified by using an exponent of 1.83 rather than 2. Some baseball stats freaks have refined it even further, but geez, we have to draw the line somewhere.
2009 Major League Baseball Regular-Season Victory Over/Unders
Lines from the Las Vegas Hilton (subject to change)
- Arizona Diamondbacks — 86 1/2
- Atlanta Braves — 84
- Baltimore Orioles — 72 1/2
- Boston Red Sox — 94
- Chicago Cubs — 91 1/2
- Chicago White Sox — 78
- Cincinnati Reds — 79 1/2
- Cleveland Indians — 85 1/2
- Colorado Rockies — 78
- Detroit Tigers — 82
- Florida Marlins — 75 1/2
- Houston Astros — 74
- Kansas City Royals — 76
- L.A. Angels — 87 1/2
- L.A. Dodgers — 84
- Milwaukee Brewers — 81
- Minnesota Twins — 84
- New York Mets — 89
- New York Yankees — 95 1/2
- Oakland Athletics — 82 1/2
- Philadelphia Phillies — 88 1/2
- Pittsburgh Pirates — 69
- San Diego Padres — 71
- San Francisco Giants — 80
- Seattle Mariners — 73
- St. Louis Cardinals — 82 1/2
- Tampa Bay Rays — 88 1/2
- Texas Rangers — 73 1/2
- Toronto Blue Jays — 79 1/2
- Washington Nationals — 71 1/2
Take a look at the regular-season-victory over/under figures for the Tampa Bay Rays as they were posted in Las Vegas sports books for the past four seasons.
In 2005 the number was 71 1/2. They actually finished with 67 victories.
In 2006 it was 68 1/2. They won 61 games.
In 2007 it was 67 1/2. They won 66 — a third consecutive dismal season, a third consecutive ticket cashed for “under” bettors.
It was a shame about the Rays.
In 2008 the over/under was set at 75 victories. Oddsmakers had the right idea in adjusting Tampa’s total upward. They just didn’t go far enough, as the Rays won 97 regular-season games and the American League pennant.
Their breakout performance a year ago is the primary reason the Rays’ over/under in total victories for 2009 carries the largest differential in baseball as compared with 2008 preseason figures.
When the Las Vegas Hilton sports book posted its opening numbers for the 2009 baseball season, Tampa Bay’s total was set at 88 1/2. That’s 8 1/2 fewer games than the Rays won last season, but a major-league-high 13 1/2 more than last year’s preseason over/under.
The New York Yankees (over/under 95 1/2 victories) and the Boston Red Sox (94), both perennial favorites in this form of wagering, sit atop the board at the Hilton sports book. The Red Sox won 95 games last season to the Yankees’ 89. The Yankees’ projected total for 2009 is actually lower than it was heading into 2007 (97 1/2), 2006 (97 1/2) or 2005 (101 1/2).
Compared with their actual victory totals in the 2008 regular season, the three teams expected to show the greatest improvement this year are the Atlanta Braves, Seattle Mariners and Washington Nationals.
The Braves, 72-90 last year, opened with a season victory total of 84 after adding Derek Lowe, Javier Vazquez and Kenshin Kawakami to their starting rotation.
The Mariners finished 61-101 last season, the worst record in the AL. They opened with an over/under of 73 for 2009, thanks in part to the return of Ken Griffey Jr. via free agency and the addition of Franklin Gutierrez and Endy Chavez in the outfield. Seattle also beefed up its department of “sabermetrics” (defined by author Bill James as “a search for objective knowledge about baseball”) by hiring Tom Tango as a consultant in statistical analysis.
The Nationals were 59-102 last season, the worst record in the majors, yet their over/under for 2009 opened at 71 1/2 victories. Some of the increase can be attributed to the notion that things cannot get much worse for the Nats, and some to the offseason signing of slugger Adam Dunn to a two-year contract.
Speaking of sabermetrics, bettors who subscribe to the theories of influential professional handicapper Pythagoras (who had one name only, before it was cool) will take a hard look at playing the Toronto Blue Jays “over” 79 1/2 victories. Toronto finished with 86 victories last season, though its Pythagorean winning percentage (see sidebar) suggested 92 victories. The Jays’ lowered expectations for 2009 are largely a result of the loss of right-hander A.J. Burnett, who signed a five-year deal with the Yankees in December.
The three teams projected to sustain the biggest drop-offs are the Los Angeles Angels, Houston Astros and Chicago White Sox.
The Angels won 100 games last season, tops in the AL, yet opened with an over/under of 87 1/2 for 2009 after losing Mark Teixeira and Francisco Rodriguez to free agency. It didn’t help that their Pythagorean record last season was just 88-74.
The Astros won 86 games in real life but just 77 in the realm of Pythagoras, so they could be headed for a fall. The Hilton oddsmakers opened them at over/under 74.
The White Sox were 89-74 last year — precisely their Pythagorean record as well — but they could suffer from a lack of cohesion after revamping their roster during the offseason. Their over/under has been installed at 78 victories for 2009.
By the way, the Rays’ Pythagorean record last year was 93-69 — impressive, but a challenge to match.