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Run differential, and arguing about how good the 2015 Rangers really are

The Rangers are outperforming projections, which has led to people fighting about what that means

Jerome Miron-USA TODAY Sports

The Texas Rangers were underdogs heading into the season.  Many prognosticators expected them to finish in last place in the A.L. West, and the general consensus was that they were a .500 team at best, especially once Yu Darvish went down for the season.  And even mediocrity seemed ambitious in mid-May, when Texas was 9.5 games back in the A.L. West with a 16-23 record.

Yet, here we are, with two and a half weeks to go in the season, Texas has a 78-67 record, is 1.5 games up in the West, and has a very good chance of being in the postseason this year.

So of course, people are fighting.

Specifically, there is fighting about how good the 2015 Rangers really are.  Texas has allowed 660 runs against 647 runs scored, a -13 run differential that would normally result in a 71-74 record.  Statistical projections and modeling generally anticipate that the Rangers will be roughly a .500 team the rest of the way, with the exact percentage often being a few percentage points under .500.  The reaction by fans, and some in the media, is that the Rangers are being discredited, disrespected, etc. when this is pointed out.

The most common reaction seems to be, "Who cares that there's a negative run differential -- at this point in the season, you are what the record shows you are."

Yes, the Rangers aren't going to get docked wins from their actual record to account for the the fact that their run differential up to this point of the season isn't as good as their record.  The wins and losses happened, and are in the books.  At the same time, though, the actual performances that led to the runs scored and allowed actually happened.  As B-R explains, in explaining Pythagorean Winning Percentage:

The rationale behind Pythagorean Winning Percentage is that, while winning as many games as possible is still the ultimate goal of a baseball team, a team's run differential (once a sufficient number of games have been played) provides a better idea of how well a team is actually playing. Therefore, barring personnel issues (injuries, trades), a team's actual W-L record will approach the Pythagorean Expected W-L record over time, not the other way around.

Part of the resistance to this notion seems to be driven by the difficulty folks have in grokking what is a small sample size...a common response is, well, maybe you'll deviate from this over a short-term, but if you're exceeding your expected win-loss record over the course of a whole season, then it must be because you're really better than what the run differential expects.  The reality is that you're going to have variations over 162 games, and it takes much longer than that for things to even out.  If you have a negative run differential over the course of a season, its most likely an indicator that you've played below-average ball over the course of the season, even if you have a winning record.

But if you have a winning record...who really cares?  Its ultimately an academic retrospective discussion.  When the Rangers' record is worse than what their run differential shows, we talk about it and acknowledge it.  If they are better, it seems it would be hypocritical to stick my head in the sand and pretend that doesn't exist.

Of course, the follow up to that is that this isn't the same team as it was back in April, and that's absolutely the case.  Cole Hamels is here.  Martin Perez is here.  Derek Holland is here.  Sam Dyson is here.  Jake Diekman, Andrew Faulkner, Will Venable and Mike Napoli are here.  The 2015 Texas Rangers have Nick Martinez and Wandy Rodriguez as the #3 and #4 pitchers in innings pitched this season.  The current Rangers team isn't the same as the one we've seen most of this season.

For some reason, though, it seems to upset folks when this issue is discussed.  I had this exchange on Twitter last night:

Apparently, because I think the 2015 Rangers team has, over the course of the season, been an average team, I'm a negative nancy, a whiner, someone who revels in the bad and wants to see the team fail.

And that couldn't be farther from the truth.

Part of what makes this season so awesome is that it is so unexpected, is that, after several years of every break seemingly going the wrong way, the Baseball Gods have been, so far, pretty gracious.  I predicted an 82-80 record before the season, before Derek Holland got hurt, and many folks thought that was wildly optimistic.  The fact that the Rangers keep pulling games out, keep exceeding expectations, keep defying the odds is part of what makes this so fun.

And it is a reminder of how much variation there can be in baseball, of why its so silly to speak in absolute terms about how a team can't possibly contend for X years.  Its a reminder of why there's always reason for hope in the spring.  And its part of why I relish seeing those who went HAM on the Rangers being a lost cause, not just in 2015 but beyond, having to crawfish now.

I feel good about this Texas Rangers team.  I think this team will make the playoffs.  But even if they don't, or even if they lose in a Wild Card game or get swept in the ALDS, this season has been a good one.  We are in a playoff race and leading the division in mid-September, something every one of us would have taken in a heartbeat back in March.  And whether the run differential is negative or whether the "true talent" of the team over the course of the full season isn't what that would describe doesn't change that one bit.

So let's keep having fun.