"I think in the last five years ago it's really picked up. People are talking about it. Managers are talking about it. And I think that comes from the fact that baseball people themselves are looking at different ways to measure their team, or other team's, success," Bill Arnold of the Sports Features Group, who created Beyond the Box Score, told MLB.com last season.
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There is a debate over its value as a predictor, however. Some believe that a team with a big edge in scoring but a poor record will soon turn the corner. Or that the breaks will eventually even out for a team that is winning a lot of close games.
Others simply point to the 2012 Orioles. Baltimore scored just seven more runs than it allowed that season. Its Pythagorean record, according to an equation developed by sabermetrics godfather Bill James and based on run differential, should have been 82-80. Instead the O's won 93 games. The reason: They were a remarkable 29-9 in games decided by one run.
So, with the playoffs about to begin, let's take a look at the correlation between run differential and postseason success.
If outscoring opponents by a wide margin was the only criterion for winning the World Series, the Blue Jays could have their parade right now. Toronto is +221 for the season, and nobody else is even close.
Here's how this year's playoff teams ranked:
- Blue Jays, +221
- Cardinals, +122
- Astros, +111
- Pirates, +101
- Royals, + 83
- Cubs, + 81
- Dodgers, + 72
- Mets, + 70
- Yankees, + 66
- Rangers, + 18
In the last five years, though, only one team that has led the Major Leagues in run differential has even made it to the World Series. That would be the 2013 Red Sox.
One of the others was knocked out in the Wild Card Game (2014 Athletics), two lost in the Division Series ('12 Nationals, '11 Yankees) and one advanced to the League Championship Series before falling ('10 Yankees).
Conversely, the 2014 Royals had only a +27 in the regular season and took the World Series all the way to the ninth inning of the seventh game. While winning world championships in '12 and '14, the Giants finished eighth among the 10 postseason teams in that category.
However, in the eight years prior to that, four of the teams that led in that category went to the World Series, and three of them won it all.
Here's a look at the last three postseasons, since MLB added a second Wild Card in each league:
- Athletics, +157 -- Wild Card
- Angels, +143 -- Division Series
- Nationals, +131 -- Division Series
- Orioles, +112 -- League Championship Series
- Dodgers, +101 -- Division Series
- Tigers, + 52 -- Division Series
- Pirates, + 51 -- Wild Card
- Giants, + 51 -- WON WORLD SERIES
- Royals, + 27 -- World Series
- Cardinals, + 16 -- League Championship Series
- Red Sox, +197 -- WON WORLD SERIES
- Cardinals, +187 -- World Series
- Tigers, +172 -- League Championship Series
- Athletics, +142-- Division Series
- Braves, +140-- Division Series
- Reds, +109 -- Wild Card
- Indians, + 83 -- Wild Card
- Dodgers, + 67 -- League Championship Series
- Pirates, + 57 -- Division Series
- Rays, + 54 -- Division Series
Nationals, +137 -- Division Series
Yankees, +136 -- League Championship Series
Cardinals, +117 -- League Championship Series
Rangers, +101 -- Wild Card
Braves, +100 -- Wild Card
Athletics, + 99 -- Division Series
Reds, + 81 -- Division Series
Giants, + 69 -- WON WORLD SERIES
Tigers, + 56 -- World Series
Orioles, + 7 -- Division Series
And here's how the run differential leader fared in the decade prior to that:
- 2011 Yankees, +210 -- Division Series
- 2010 Yankees, +166 -- League Championship Series
- 2009 Yankees, +190 -- WON WORLD SERIES
- 2008 Cubs, +170 -- Division Series
- 2007 Red Sox, +206 -- WON WORLD SERIES
- 2006 Yankees, +163 -- Division Series
- 2005 Cardinals, +171 -- League Championship Series
- 2004 Cardinals, +196 -- World Series
- 2003 Braves, +167 -- Division Series
- 2002 Angels, +207 -- WON WORLD SERIES
There is a one recent trend that will be good news for Blue Jays fans, though, if Toronto advances to the World Series. In seven of the last eight years, the Fall Classic has been won by the team with the better regular-season run differential.
Just like in 1960 when the Pirates (+141) beat the Yankees (+119).