Structural Unfairness In Baseball's Divisions
A couple of weeks ago, I had planned on penning an article for SI.com on MLB's wild-haired proposal to reshuffle the divisions in order to make them more equitable. My thesis was to be that there was little reason to do so. Teams ebb and flow and the shuffling is unnecessary. The record of AL East teams against the other divisions is barely over .500 since 1996, so the AL East isn't that much of a powerhouse anyway. To boot, when looking at 90-win teams that missed the playoffs, the AL East housed fewer of these teams than either of the other two AL divisions. I'm glad I didn't write that article, because I'd have been wrong. Here, I'll show why.
Let it be known, I still think the proposal is a hare-brained scheme. Swapping strong AL East teams with weaker ones would be tantamount to just handing the flag to Boston and New York. Additionally it wouldn't be fair to those "weak" AL teams - after all, maybe they'd surprise people and make a run. Plus the whole thing just seems jury-rigged and unseemly. Still, there is a real question of what structural advantages and disadvantages are built into the current system.
The Effect of Market Size on Winning
Certainly some teams figure to be better than others long-term. Market forces are a very real phenomenon, and the fact is that big-markets and owners with deep pockets can have a strong effect on a team's performance. How those big-market teams are distributed among the divisions can have a strong impact on the game.
As a first step, I ranked all 30 teams based upon "market size", and when I mean market size, I mean not only the size of the market, but also things like ownership's willing to spend money, etc. This was somewhat subjective, however I think my ordering was reasonable. I then assigned each team a market "value" according to the normal distribution, so teams like the Dodgers and Yankees got the highest scores, and teams like the Rays and Pirates got the lowest. I then did a regression to predict WPCT (data pulled from 1995-2009) from this market size variable. As expected, the two were significantly correlated. The predicted WPCT for the biggest team (the Yankees), was .558. That translates to about 90 wins, which I think is a pretty good over-under for a future undetermined future Yankees team. The market size advantage drops off quickly after that. The Red Sox have an average WPCT of .537, translating to 87 wins. Meanwhile, most teams are clustered close to .500. As you can see, market size matters but doesn't hand a team anything. Overall, the WPCT's predicted from market size had a standard deviation of .027.
Now, the standard deviation of team WPCT as a whole since 1996 has been .072. The factors adding up to this .072 SD can be described in the following equation:
Total Variance = (Between Franchise Variance Due to Market Size) + (Within Franchise Variance Due to Other Factors) + (Team Variance Due to Luck)
The "Other Factors" translates to teams' ebb and flow of talent - sometimes the same franchise will produce a good team, and sometimes it will produce a bad team. Since we know all of the other variables except this one, we can easily solve for it and we get the following values:
Total SD = .072
Market Size SD = .027
Within Team SD = .054
Luck SD = .039
And it all adds up: (.072)^2 = (.027)^2 + (.054)^2 + (.039)^2
Knowing all of the factors that go into a team's performance, I set up a simulation to estimate the probabilities of each team making the playoffs. The simulation was set up to play a balanced schedule against each of the other teams in the league, plus a handful of "interleague" games against a .500 opponent (I didn't have time to program in the unbalanced schedule unfortunately, although I think this is a relatively small issue). So, how much structural disparity is there in baseball? Are teams like the Rays really at a huge disadvantage due to playing in the AL East?
Long Term Playoff Probabilities
The following chart shows what happens in the simulation:
Indeed, the Rays are at the biggest disadvantage of any team in baseball. As one of baseball's smallest market teams, and in one of baseball's toughest divisions, they have just a 7% chance to make the playoffs. To clarify, these percentages are for some theoretical year in the future, NOT taking into account the personnel currently on the club, the quality of the management, etc. The team with the biggest advantage is the Yankees, who have a 57% chance to make the playoffs in any given year. Of course, these numbers are quite dependent on the market size ratings I assigned teams earlier. And, my guesses aren't exactly the gold standard.
Additionally, it's not Bud Selig's fault if the Rays and Pirates are small market clubs. A large part of the reason for the small probability for teams like the Rays is due to their own small-market nature. That's useful to know, but the impetus of the piece was whether the divisions themselves were unfair to certain teams.
Playoff Probabilities Given an Average Team
To take the nature of the particular team out of it, I changed the team in question's long-term average WPCT to .500. For instance, if the Rays were not small market, and instead had an expected WPCT of .500, how often would they make the playoffs? And is that probability higher or lower than it would be in other divisions? Below is a chart showing the probability of making the playoffs, assuming that the target team has an average WPCT of .500.
As it turns out, the Rays are still getting the shortest stick in baseball. Even assuming they have no market disadvantages (or advantages), they have just a 20% probability of making the playoffs in a given year. How does this compare to other teams? The most favorable structural advantage goes to the Los Angeles Angels. Assuming no market advantages, their probability of making the playoffs is 31%. That means that just due to their competition, the Angels will make the playoffs three times for every two times that Tampa makes the playoffs. Not surprisingly, besting the Yankees, Red Sox, Orioles, and Blue Jays is tougher than beating the Rangers, Mariners, and A's. For one, it's easier to beat three other teams than four. And for another, the Red Sox and Yankees are usually tougher to beat than any of the other AL West teams. Those are observations any fan could make, but the effect on the probability of winning is quantified here.
The rest of the AL West is also substantially easier than the AL East. Oakland has a 25% chance of making the playoffs, while the Mariners and Rangers push 30%.
Additionally, the AL Central is a great place to call home. Again, assuming no market advantages or disadvantages for the target team, each team has a 28%-30% chance of making the playoffs. Again, this is a far cry from the Rays' 20%.
How about the Yankees themselves? Again, making their average ability equal to .500, they figure to make the playoffs 26% of the time. These odds are higher than that of the Rays (because they don't have to face a powerhouse Yankee team), but still lower than any AL Central team or most of the AL West. The AL East is tough even for the big dogs.
Now let's move over to the National League. The first thing to notice is that it's generally tougher to win in the NL than the AL. This makes sense because there are more teams to beat in the NL, but the same number of playoff spots. Many of the teams approach the Rays' probability of winning. In the NL East, the Marlins have a 21% chance of making the playoffs, in the NL Central the Pirates have a 22% chance of winning, and in the NL West, the Padres have a 21% chance of winning. However, there is not quite as much disparity among the larger market clubs. Of the large market players, the Cubs have just a 26% chance to make the playoffs, while the Mets have a 25% chance, and the Dodgers have a 29% chance. This is in contrast to the AL, where a number of teams have probabilities approaching 30%. A summary of the average probability of making the playoffs in each division is below.
So what's the conclusion? Yes, some teams face significantly higher hurdles than others. It's not just the Rays that face the problem, but many other National League clubs as well. Paradoxically, because they don't have to play themselves, the large market teams face an easier schedule than their small market counterparts. Situations like these create the imbalances we see here.
The AL East is indeed a tough division, but it's actually about the same toughness as the NL East. It's actually the AL Central and the AL West that are the outliers, in that they are easier divisions than the rest of baseball. If MLB is keen on evening that up, one potential solution is to move Toronto to the AL Central and the Twins to the AL West. That would make the AL East a four-team division and hence easier to win, would toughen the AL Central by adding the Blue Jays instead of the Twins, and would toughen the AL West by adding a fifth team. The NL's division imbalance is solved nicely by having the smaller market teams populate the NL Central. The fact that it has six teams counteracts the fact that the teams are likely to be of a little lower quality, and hence the NL Central is about as easy to win as the West or East.
Is the model perfect? No, because it's difficult to estimate each team's average long-term WPCT. Still, the underlying conclusions, especially regarding which divisions are easiest or hardest, should hold. The teams from the AL East have a legitimate beef, especially the Rays. However, compared to other AL divisions, the National League is also getting a raw deal. These types of inequities are part of the game, but they should be minimized if possible. With these numbers, it hopefully be more clear on how large these inequities really are. Whether baseball will do something about it remains to be seen.