Does run differential matter for Mets?

July, 11, 2014
NEW YORK -- Sandy Alderson has asserted that the Mets' run differential, currently plus-four, suggests the Mets have underperformed. Or, at least, the GM indicated the Mets should perform better the remainder of the season because their run differential is positive.

Do historical numbers bear that out as the Mets enter Friday's series against the Marlins at 42-50?

Here are the Mets' run differentials after games of July 10 for every season since 2002. Next to it is the winning percentage the remainder of that season. If Alderson's theory holds, then the positive post-July 10 winning percentages should be tied to the positive run differentials during the first portion of the season.

2006: +69 .603
2010: +46 .427
2008: +28 .586
2004: +25 .355
2007: +23 .533
2012: +20 .368
2011: +11 .437
2002: +8 .432
2005: +6 .527
2013: -26 .459
2009: -39 .390
2003: -74 .380

Only 2002 is directly analogous to the 2014 Mets -- a team with a losing record through July 10, but a positive run differential at that point. In 2002, the Mets were 43-44 after their July 10 game despite a plus-eight run differential. They went 32-42 the remainder of that season.

Statistically, there's a term known as correlation. Boiled down, two things that move in perfect harmony have a correlation of 1. Two things that move in exactly the opposite direction are minus-1. Most things fall in between.

The correlation between the Mets' run differential through their July 10 games and their winning percentages the remainder of those seasons is .497 for the seasons since 2002.

That means they move in the same direction, but not perfectly. And that, frankly, should be expected.

It stands to reason that teams that outscored their opponents during the first portion of the season would have better records during the remaining games than the Mets editions that were outscored in the opening portion. That .497 correlation falls in the middle range of what is defined as a "strong positive relationship."

Want to know what's at least an equal -- if not marginally better -- indicator of winning percentage after July 10? Winning percentage before that date.

The first percentage below is the Mets' winning percentage through games of July 10. The second is the winning percentage the remainder of that season.

2006: .596, .603
2008: .522, .586
2007: .552, .533
2005: .500, .527
2013: .455, .459
2011: .505, .437
2002: .494, .432
2010: .540, .427
2009: .471, .390
2003: .433, .380
2012: .535, .368
2004: .512, .355

The correlation between record before and after the games of July 10? It's .535 -- a hair better than run differential.
Adam Rubin has covered the Mets since 2003. He's a graduate of Mepham High School on Long Island and the Wharton School of the University of Pennsylvania. He joined ESPNNewYork after spending 10 years at the New York Daily News.
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BAD. Murphy .289
HRL. Duda 30
RBIL. Duda 92
RD. Murphy 79
OPSL. Duda .830
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SOZ. Wheeler 187