The probability of making the baseball playoffs

The other evening I heard that the Washington Nationals had a two percent change of making the playoffs. Naturally I wondered how someone had computed that probability. That led me to the site coolstandings.com where all the numbers for all the teams are laid out for everyone to see. What is really nice is the educational aspect of what they have done.

They set up two models for computing the probabilities – the “smart” model and the “dumb” model. The “dumb model assumes that each team has an even chance of winning a given game. The “smart” model takes into account the past performance of each team.

And the really nice feature is that you can compare the results from the two models over time. The differences are quite big. Currently, as of Sunday morning, September 22, the odds of Tampa Bay making the playoff is 63.6% under the “smart” model, but a much better 76.8% under the “dumb” model. On the other hand Cleveland has a 78.3% percent change under the “smart” model and only 65.8% under the “dumb” model. Why the differences. It all comes down to which teams they will play over the final week of the season.

Play with the data a bit. Look at the trends. Oh, and the Washington Nationals, their chances are now at 1.3% dispute having won every game since I first heard that they had a 2% chance the other evening. Their problem in short that they have to win just about every game while either Pittsburgh or Cincinnati collapse in this final week.