Blake Murphy Sports Writing

Title: AL East and NL East Set to Battle for Divisional Supremacy
Date: June 8, 2012
Original Source: The On Deck Circle
Synopsis: This article compared the dominance of both the AL East and NL East ahead of Interleague Play, with the divisions set to play 66 games against each other over the next two weeks.

It shouldn’t be news at this point that baseball is being dominated by an East Coast bias. Of course, I’m not referring to the generally maligned East Coast Bias of media reporting, whereby West Coast coverage falls by the wayside due to time zone differences. No, the Eastern Bias I’m referring to here is the odd but not unfamiliar dominance of Major League Baseball’s two eastern divisions, the NL East and AL East.

If you’ve been following baseball even passively for any amount of time, you no doubt understand the American League East to be a battleground of the utmost talent, the most competitive division in sports, buoyed by the big-spending Boston Red Sox and New York Yankees and the “Extra 2%” ultra-managed Tampa Bay Rays. The Toronto Blue Jays have hung around forever as the 3rd- or 4th-string, seemingly content to finish around .500 and hang their hats on the “if we only played in the Central…” excuse. As for the Orioles, well, their best days are far in the rearview mirror.

Alas, this year has been different – it’s not that the AL East isn’t dominant, it’s that all five teams are great rather than the usual two or three juggernauts plus also-rans. The AL East currently has a winning percentage of 54.2%, even higher than last year’s 52.9%, but even this is misleading as it ignores the fact that these teams all play 44.4% of their games against each other. Basically, the division has 44.4% of games guaranteed to produce a cumulative outcome of .500, since each inter-AL East game must have a winner and a loser. Thus, the dominance in Win% means that last year, those extra wins above .500 were generated in just 55.6% of the schedule. To clarify, that means AL East teams won 55.2% of the time last year against non-AL East teams. This year what it means is that these five dominant AL East teams have won just 50% of their games against each other (obviously), but an astonishing 58.1% against non-divisional opponents.

But like I said, other than the fact that contributions are coming from all five teams rather than “just” three or four, this is old hat for the AL East. This year, however, the National League East has gotten in on the action as well, sporting a nearly identical win-loss record to its AL counterpart.

Last year, the NL East won an impressive 51.9% of its games, but this figure was misleading since the Phillies went 42 games over .500 and the division was home to three sub-.500 teams. This year, though, the division is winning at a 54.2% clip and it’s only the Phillies that are under .500, and by just three games at that. Like the AL East, the NL East can only go .500 against itself, so this dominance comes exclusively from games against opposing divisions, and they’ve produced a 57% win rate against non-divisional opponents in 2012 (this is slightly lower than the AL East because the NL East has played a smaller proportion of inter-divisional games so far).

So, the East divisions are winning a lot. Are people buying in, though, or is it a fluke? Well, Grantland’s Jonah Kericurrently has the East teams ranked 2-3-4-5-9-10-11-12-14-18 in his latest version of The 30, his weekly power rankings segment. ESPN Power Rankings has them ranked 3-5-7-8-9-10-12-15-16-18, essentially agreeing on the distribution and confirming there are no bottom-10 teams to be found. One additional place to look is ESPN’s RPI rankings, a relatively basic attempt at ranking teams based on opponent quality – the formula simply takes 25% of a team’s winning percentage, 50% of their opponent’s winning percentage, and 25% of the opponent’s opponent’s winning percentage. This, in theory, should show a team’s success once controlled for the quality of competition, though it’s obviously not perfect. If we employ this metric, the teams rank 1-2-3-4-5-6-7-11-13-20, so the RPI would suggest that power rankings are actually under-estimating the quality of these teams due to the relative schedule strength they face by constantly having to beat up on each other.

So, the AL and NL East are dominant divisions. It’s taken me 650 words to get there, but you could have found this out by watching a few ball games or looking at the standings yourself. If you think the records are a bit fluky, I’ll direct your attention to the run differentials of the teams (generally a better predictor of future success than current won-loss record), of which six teams have a large positive figure, two have a small negative figure, and two more have moderate negative figures. As a clarification, Expected W-L% projects win rate based on run differential, and this metric has the teams ranked 4-5-7-8-9-12-14-16-18-19, and again, this is without controlling for opponent quality, since it’s strictly a +/- score. So yeah, these divisions are great.

But which one is better? The NL is generally considered weaker, but since both leagues will end up with a .500 record against themselves, Interleague Play is a small sample we can use to try and determine which side has the more difficult path to these ridiculous win rates. The AL has had a winning record against the NL for the past eight seasons, not including a 24-18 record so far this year, so it can be pretty reasonably suggested that the American League is the stronger of the two. It would follow, then, that given similar win totals and run differentials, the AL East is stronger than the NL East, too.

But luckily for us, we don’t have to make that assumption, if we’re willing to accept a 66-game sample as an indicator for the time being.

Starting tonight, the AL East and NL East begin doing battle a great deal over the next two weeks, as Interleague Play rolls out in full force. For five straight series, teams will play opponents from the opposite league (except for two NL teams at a time, since there are 16 NL and only 14 AL squads), and this year the East divisions match up against each other with great regularity. The chart below shows the current records of each division, as well as their Interleague slate for the next five series. The NL East hosts 33 games against the AL East, while the AL East hosts 33 games against the NL East. Obviously, the schedule won’t work out perfectly with each team playing each other both home and away to neutralize imbalances, but a 66-game sample should give us a rough idea of how these two divisions stack up against each other.

Interestingly enough, the weakest team in either division by record, the Phillies, has the easiest slate, only playing three series against the AL East instead of four or five like its divisional counterparts. Similarly, the Mets, Orioles, and Jays get a single-series reprieve against the Reds, Pirates, and Brewers, respectively (not that these are particularly bad teams). Regardless, none of these teams have what you would call an easy couple of weeks.

Interleague Play is always fun just for a different look at baseball and the intricacies of teams playing under slightly different sets of rules in rarely witnessed match-ups. For Jays fans, the chance to see Stephen Strasburg and Bryce Harper is enticing, though you miss your chance at a Roy Halladay sighting this year due to his current injury. Yankees and Mets fans get to wage war (twice), Washington and Baltimore get to engage in their version of a subway series, the Beltway Series, and the Marlins get to welcome two big-name teams to their new ballpark in Boston and cross-state rival Tampa Bay.

There’s something positive for every team here….except, of course, for the difficulty of the schedule. But which side has it worse? We’ll have a better idea in two weeks…in 22 series…in 66 games.