The 2015 NL East was the worst division in a decade, despite sending a team to the World Series
Given the assorted other advances in the game, it's a little weird we're still talking about divisions. Divisions have been there all along, so it's not like they're some unusual concept, but a perfectly balanced version of baseball doesn't have them. It's because of the divisional structure that we had the Cubs and the Pirates forced into a wild-card showdown despite finishing second and third in the National League standings. There's a good argument to be made that divisions should be completely abolished.
But, you know, that's not on the horizon. Divisions are presumably here for a while. There are practical considerations that get in the way of idealized baseball. Our reality is one with divisions, and with unbalanced schedules. Sometimes that helps a team, and sometimes that hurts a team. The hope is that in the long run it all evens out.
As long as there are divisions, the makeup of the divisions is going to matter. And as long as there are divisions, they'll be easy enough to analyze. For example, what follows is a plot of 2015 divisional strength. I thought about doing this in a more advanced way, by, say, folding in WAR or something, but I settled on comfortable simplicity. There are six divisions, yes? In the plot, you'll see each division's overall winning percentage, and also each division's winning percentage in games against opponents from outside the division. Within, the teams always go .500, by necessity, so that reduces the spread.
The order is probably about what you expected. The NL Central looks the best -- despite having a pair of pushovers. It sure does help to also have the three best overall records in baseball. The AL East trails by a decent margin, then things kind of flatten out until the end. Very obviously, the NL East was bad. We knew the Phillies and Braves would be terrible, but both the Marlins and the Nationals underachieved. Though the NL East wound up represented in the World Series, the division was comparatively terrible. Outside of the East, those five teams won fewer than 43% of their games. All right, none of this is new to you.
I decided it might be of greater interest to try to put this in context. So the NL East was bad. How bad was it, historically speaking? I could've gone back to the introduction of six-division baseball, but instead I just went back to the dawn of interleague play, to somewhat take into account any league disparities. So that gives me six divisions over 19 years, for a total sample of 114. Here are the 10 worst divisions, in ascending order of overall winning percentage:
10 Worst Divisions, 1997 - 2015
| Season | Division | Win% |
| 2002 | AL Central | 0.453 |
| 2003 | AL Central | 0.457 |
| 1999 | AL Central | 0.457 |
| 2005 | NL West | 0.459 |
| 2015 | NL East | 0.462 |
| 2008 | NL West | 0.463 |
| 1998 | AL Central | 0.465 |
| 2006 | NL Central | 0.467 |
| 2002 | NL Central | 0.468 |
| 2012 | AL Central | 0.468 |
There is but a single entry from this most recent season, there in fifth. The worst division observed is the 2002 AL Central, where the Twins won 94 games, and no one else was over .500. The AL Central actually gets credit for the three worst divisions of those we've looked at. But at least by this measure, this year's NL East was baseball's worst division since the 2005 NL West. So by a slim margin, that covers a whole decade.
If you look at winning percentage outside of the same division, then the NL East slides into fourth-worst. At .428, it's no match for the 2002 AL Central's .412, but it does dip past the 1999 AL Central's .439. I feel like I don't need to keep hammering this. The division was bad. It was probably the worst in 10 years. In the season ahead, it's likely the Phillies and Braves will once again struggle. The Nationals will lose some personnel, and the Mets could lose both Daniel Murphy and Yoenis Cespedes. It's way too soon to try to forecast how the division will play in 2016, but the probability is that the best team in it will benefit from a relatively soft schedule.
In case you're curious about the other side, the NL Central was strong, but it ranks tied for 11th in the interleague era. It was the strongest division in two years, since the 2013 AL East. The No. 1 strongest division was the 2002 AL West, with a very slim lead over the previous season's AL West. (In third place: a different season's AL West.) In fact, the top nine divisions all come from the American League, but that's not a total surprise, given the AL's run of league superiority. This is of little consolation to the Reds and the Brewers, who are looking up at their rivals and wondering what hope they have. If there are two teams in baseball that could stand to try to start over, it would be those. The Brewers have arguably already begun.
Just for the sake of a few closing thoughts: Over the 19 years, the AL Central has never once been baseball's strongest division. This past year was the first time in the window that the NL Central ranked No. 1. And this was the first time that the NL East ranked No. 6. A year ago, we saw more parity between divisions than we had since at least 1996. There was very little spread in divisional quality. This year was a bounce-back in that regard. Or an anti-bounce-back, depending on your perspective on parity. There was less parity, basically. That's all.
So, we're coming off a recent first for the NL Central. And we're coming off a recent first for the NL East, which was just the worst overall division baseball has seen in a decade. This has all been a reflection, but in the process of writing this, I saw that the Mariners and Rays completed a six-player trade, so now it's officially time to look ahead. Contained within is information about the 2015 baseball season. That season won't be bothering you anymore.
