FANS Playoff Probabilities – AL Version

Last week David posted projected standings generated from the FANS projections. I thought it would be interesting to dig a little deeper and investigate what it means for example to have the Yankees projected at 98 wins and the Red Sox at 94. My metric of choice will be playoff probabilities and my method will be simulation.

Before I get to the results of the simulation for the AL, let’s get into the nuts and bolts a little bit. In order to run the simulation needs the season’s schedule and each teams true talent win percentage. The simulation is a simple Monte Carlo that determines the winner of each game using random draws bounced up against log5 based winning percentages. For example, if we want to simulate the outcome of a game between Team A that has a 0.600 true talent win percentage and Team B that has a 0.450 win percentage, we first calculate the probability that A beats B using the log5 equation linked above. That calculation says that Team A should have a 0.647 winning percentage against Team B.

To simulate a game between these teams then, the simulation draws a random number between 0 and 1 and if the number is less than or equal to 0.647 then Team A wins, otherwise Team B wins. This process is repeated for all of the games for the entire season. Run the simulation for 10,000 such seasons and you have your results. Also built into the simulation is some up front uncertainty about the true talent win percentage. Before each of the 10,000 simulated seasons, the true talent win percentages for each team are varied slightly by using a random draw from a normal distribution centered at the input win percentage (which is based off of the projected standings) with a standard deviation of 0.030. For example, some seasons the Yankees will simulate as a 0.605 team, sometimes a 0.600 team and sometimes a 0.610 team. The standard deviation was derived through testing (read trial and error) and some of the comments in this thread at The Book Blog.

Now on to the results, starting with the East

East       Div Win %    WC Win %   Playoff %
Yankees          53%         27%         80%
Red Sox          26%         31%         57%
Rays             20%         28%         48%
Orioles           1%          3%          4%
Blue Jays         0%          0%          0%
Twins	         38%         1%          39%
White Sox	 24%         1%          25%
Tigers           19%         1%          20%
Indians          13%         1%          14%
Royals            6%         0%           6%
Rangers          38%         2%          40%
Mariners         27%         2%          29%
Athletics        19%         2%          21%
Angels           16%         1%          17%

and finally some other useful data points compared to historical data

Division        Avg. Wins      2002-2009 Avg Wins
East             101           99
Central           89           93
West              90           96
Wild Card         94           96

Overall nothing too shocking. According to the FANS all of the divisions should offer plenty of intrigue be it in the form of a dogfight for the division title with likely no Wild Card safety net (the West and the Central) or the powerhouses taking it to each other all season (the East).

Next up I’ll do the same with the NL.

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Anyone else think it’s sad that the Orioles have a better shot at the Wild Card than every team in AL Central and the AL West.

The A Team
The A Team

Without diving into things, I would chalk that up to some over-optimism in the data. That Orioles team has no shot at being better than two of the Yankees, Red Sox, and Rays.

Tobias F.
Tobias F.

Yeah that’s pretty messed up. They’re basically saying that they think the Orioles are better than everyone of those teams which I simply can’t buy.(especially considering all the games they’ll have to play against the AL East)

I also don’t buy the fact that the Rays have a better chance to make the playoffs than the Twins even though I do think they are a better team. I just think it’s much more likely that the Twins would finish better than the Tigers and White Sox than the Rays finishing ahead of the Yankees or Red Sox.


The Rays were a very good team last year (that underperformed) and they’ve only gotten better.

Tobias F.
Tobias F.

True the Rays are a good team and if they were in any other division in baseball I would say they would probably be the favorites in that division but there in the AL East and I would still say they are a step below NY and Boston and I think the chances of them being better than them is rather slim. Even though they did get better they still finished 11 games behind 2nd place Boston last year and were 90 runs behind them in terms of run differential, so needless to say they were a ways behind them. Yes I know 2009 isn’t a constant but that is a really big gap to make up.

And even though Tampa is improved I think Boston maybe improved as well or at the very least stayed the same. They improved their defense greatly with the additions of Scutaro and Cameron, they improved their rotation with Lackey and if Dice-BB is throwing as good as people claim he is he could help them out too.

So it’s really not much of a knock on Tampa, I think they maybe the 3rd best team in baseball but unfortunately for them the best 2 reside in the same division. I would say that Boston and NYY are definitely better than TB but I wouldn’t say any other team in the Central is definitely better than Minnesota which is why I think the Twins have a better shot to get in the playoffs than them.

Sky Kalkman

If the Orioles have a crazy good year, they probably still won’t win the division, but might win the wild card.

If an AL West team has a crazy good year, they’ll probably win the division, but not the Wild Card.

If you look at the projected standings from David’s post last week, the Orioles are behind each of the AL West teams.