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%
Central Twins 38% 1% 39% White Sox 24% 1% 25% Tigers 19% 1% 20% Indians 13% 1% 14% Royals 6% 0% 6%
West 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.
Steve's ramblings about baseball can also be found at Beyond the Box Score and Play a Hard Nine or you can follow him on Twitter
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.
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.
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.
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.
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.
Nice methodology. The Wild Card odds just ‘feel’ a little off but I can’t quite come up with a reason why they should be different. Nice explanation of some pretty statsy stuff. I knew exactly what you were talking about which means you explained it very well.
I agree that they do feel a little off too. I think part of it is when the Orioles happen to win 90ish games they are still only in play for the wildcard, but when say the Indians win 90ish games they win the division
Heh I replied to the wrong person, and you just said to him what I said to you 🙂
And thanks for the compliments
I don’t think it would materially change the results, but would you want to include a home field advantage?
Using the example above Team A gets a 0.647 against Team B. Would it be better if that was about a 0.700 when Team A is home and about 0.600 when Team B is at home? I just guessed at the “new” numbers, but home field advantage is pretty well known.
Does home field advantage matter for good or bad teams more? I would guess it would matter more for bad teams, and thus the bad teams might get bumped up some (but not much, and maybe not enough to even round to a different %). Just kind of throwing it out there without any statsy support other than the well known homefield advantage.
This would be a moot point in general, but sometimes a team like the Twins play the Red Sox 4 times at home and two on the road, and a team like the Tigers play them 3 and 3. This could be that one game difference a handful of times per 10,000.
Unless you believe home-field advantage is greater against certain teams than others, the HFA will wash out since no team plays more than 81 home games. Even if there is some effect, it is small and will not be relevant here.
Home field win % is usually around 55%. Even assuming this is the same for each team, if the Team A is a 0.600 true talent, let’s assume they would be about a 0.660 opponent neutral home team and a 0.540 opponent neutral road team. Using these would change the log5 outputs for each game (assuming we don’t double count the effect and do it all statistically appropriate)
Would the effect on the log5 output be the same for all team talent levels?
Maybe I’m missing something here but looking at a team like the Twins or Rangers, how can they have a playoff% of ~40% and then only win the world series ~2% of the time.
If you assume playoff wins are a crapshoot which most people assume is approximately correct since its such a small sample the odds of winning the WS should be higher I think.
For example:
Playoff% = 40%
Odds of winning any series = 50%
Playoff% + winning one series = 20%
Playoff% + winning two series = 10%
Playoff% + winning two series + world series = 5%
The absolute difference between 5% and 1% is pretty small but the relative difference is pretty massive. Just wondering what you think about this.
The WC is winning the wild card. I haven’t done anything on playoffs yet.. although I might
Despite the misinterpretation, 2% sounds pretty damn close. The odds of winning each series are not 50% they’re based on the true talent level of the teams. So as an example, the Rangers may have a 45% chance to beat the Red Sox in the DS, a 40% chance to beat the Yankees in the CS, and a 45% chance to beat the Phillies in the WS. .4*.45*.4*.45=3.2%
just thinking aloud.
“Overall nothing too shocking”?
I think the Angels fans might disagree.
Facts surprise Angels fans all the time.
Projections surprise Angel fans. ‘Facts’ do not.
Although as an Angel fan myself, I am not surprised by the final standings in the FANS AL West. It’s consistent with the impression given by various projection ‘systems’. Interesting stuff, however I look forward to the games being played.
Do you have sufficient evidence to back up your claim?
It’s the same as PECOTAs’ projected standings for the AL West, fwiw.
Does the wild card column take into account the division winning column or something?
How can the Yankees have a better chance of winning the division(53%, 1st) and making the playoffs(80%, 1st) than winning the wild card(27%, 2nd)?
I’m not sure I’m exactly tracking your question. The Div and WC columns are mutually exclusive, you either do one or the other… Basically the Red Sox win the wild card the most because they are in second more than the Yankees.
Does this account for the Nathan injury? Might that make the whitesox favorites in the central now.
I’m going to guess ‘no’ and ‘tied’
As was explained yesterday, bullpen chaining could sap a lot of value out of that Twins unit. But the Twins had a nice lead over the Sox in the Fan standings, so I doubt their positions switched.