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Why You Should Care About Playoff Odds

This morning, David Appelman announced our new Playoff Odds section on FanGraphs, which provides forecasts for the rest of the season and turns those into the chances of each team advancing to each level of the postseason, whether it be capturing the wild card, advancing to the division series, or winning each round of the playoffs. It’s a pretty nifty tool, and there’s a lot to be gleaned from the data, so I wanted to use a few examples from the current playoff odds page to illustrate some of the features now included on the site.

The Importance of Remaining Schedules

Since we rolled out our new Standings page earlier this year, we’ve had expected rest-of-season winning percentage for each team all season long, which is a nice way to look at the relative strength of each team. And since we had a rest-of-season forecast and we already knew what teams had done in the past, it wasn’t that difficult to combine them into an updated final win total. However, there was a piece missing; the actual schedules each team would play over the rest of the year.

A few months ago, that wasn’t a big deal, as the variance in strength of schedule over half a season isn’t going to be very large. However, with just a month to go, there are certainly teams that have much easier competition down the stretch than others, and this difference really begins to show up when looking at the new Playoff Odds data.

For instance, on our Standings page, the Nationals rest-of-season Win% is .539. The Steamer/ZIPS projections haven’t given up on Washington as an above average team, but it sees them as a mid-tier good team, not any kind of huge standout, and unlikely to be able to make up enough ground to make a serious playoff push.

However, on our new Playoff Odds page, the Nationals rest-of-season Win% is .582, the third highest mark of any team in baseball. At first, when saw that gap, we figured there was probably some kind of error in the data, or something had gone wrong in writing the code. However, that really just reflects the fact that the Nationals schedule the rest of the year is a cakewalk.

Here is the expected winning percentage for each match-up the Nationals have over the rest of the season:

Vs Marlins (9 games): 63.2%
Vs Mets (7 games): 59.2%
Vs Phillies (6 games): 57.2%
Vs D’Backs (3 games): 53.7%
Vs Braves (3 games): 50.6%
Vs Cardinals (3 Games): 48.4%

22 of their final 31 games come against three of the worst teams in the National League. This is the easiest schedule any team has to play the rest of the year, and once these specific match-ups are accounted for, the Nationals expected winning percentage goes up significantly. As a result, our FG projection mode gives them a 13% chance of capturing one of the spots in the wild card play-in game, probably a much higher chance than you might expect given their current situation. While we might all be used to looking at games back and games remaining and doing the math in our head, the strength of schedule is a real factor that can make a difference, and that’s a significant advantage of using these playoff odds figures.

Is Making the Wild Card Game Equal to Making the Playoffs?

CoolStandings has been displaying playoff odds for years, and the term has always been kind of self explanatory, since there was no real differentiation in between a division title or a wild card berth once the post-season began. Now, however, there is a huge difference between winning your division and having to play a winner-take-all elimination game for the right to advance to the division series, and it’s a fair question to wonder what “playoff odds” should actually be. Previously, they’ve just been the chances of winning the division added to the chances of winning the wild card, but now, those two things are not equal in value. But, at the same time, the wild card game is part of the playoffs; it could be looked at as a best of one series instead of a best of five, and I don’t know that we want to start using series length to determine what is and what is not considered the postseason.

So, we’ve split the baby and decided to show playoff odds several ways. On the Playoff Odds page, you’ll find POFF, which is just the standard way of showing playoff odds, adding a team’s chances of winning the division and winning the wild card together. However, we also have DOFF, which is a team’s chance of making the division series round, so the math includes the chances of winning the division plus the chance of winning the wild card play-in game, not just reaching it. This is what would have been considered “playoff odds” before the addition of the wild card game.

The changes to the playoffs have made it so that the term “playoff odds” isn’t quite so easy to define, so we’ve just gone ahead and provided the answers to both questions that could theoretically be described as asking what a team’s playoff odds are. And then, for good measure, we’re also showing a team’s chances of winning each subsequent round, so that you can also reference a particular team’s chances of winning their Division Series, Championship Series, and World Series.

Choose Your Methodology

As David noted in the roll-out, there are three different methods to calculating Playoff Odds on the page. The primary method, which is the one I’d imagine most of us will use as our default, is the FanGraphs Projection method, which includes forecasted data from the Steamer and ZIPS projection systems and combines it with updated depth charts maintained daily by our FG authors. This method provides not only the largest sample of data for each player and team, but also includes all recent changes to a team’s roster, whether it be from a new acquisition or an injury that will force the team to reallocate playing time.

However, we also are carrying over the two prior modes from coolstandings, which they’ve set up to run throughout almost all of baseball history. Season to date mode — called “Smart Mode” in their parlance — only uses 2013 data as the inputs, and creates a pythagorean expectation of a team’s true talent level, with recent performance weighted more heavily. If you think that teams should only be evaluated on what they’ve done this season, and not on any prior season data, then this is the mode for you.

We also have Coin Flip mode — what “Dumb Mode” was called on coolstandings — which is exactly what it sounds like. Every match-up, even a Tigers/Astros game, would award 50-50 odds of winning to each team. We probably won’t be using it for analytical purposes much, but it’s there if you want to see how things would play out in a universe where every team was exactly the same.

We hope you enjoy these new playoff odds, and find them as useful as we do. We’re excited to have them on the site, and you can expect to see them referenced pretty frequently over the rest of the season.