A Different Look at Post Season Odds

Just getting set to score the Rockies/Dodgers game tonight at Coors Field with Derek Lowe up against Rodrigo Lopez. Lopez has pitched surprisingly well this season giving up 2 runs and 6 hits in 7 innings against Arizona on April 4th and one run on 5 hits in 6 innings against the Dodgers on April 10th. We'll see what he has tonight.

Since we're early in the season and the discussion at this time of year always turns to small sample sizes I thought I'd take a different look at post season odds than the one we use on Baseball Prospectus where the system uses our adjusted standings and runs simulations of 1,000,000 seasons to determine the probability of each team winning their division, taking the wild card, and making it to the postseason. There are also ELO and PECOTA adjusted versions and overall that approach is similar to the kinds of simulations I've run in the past for looking at postseason odds.

What I did here was different and is instead rooted in sort of the inverse of the uniformitarian philosophy embodied by the phrase "the present is the key to the past". In other words, it's a view from the historical record.

The first table below compares each 2007 team's record as of this afternoon to all other teams who have ever had that record and then includes two pieces of information - the average final winning percentage of all of those teams and the percentage of the time those teams reached the post season.

 W  L Teams FinalPct PSPct  Teams
10  4   149   0.560  0.302  Dodgers
 8  4   266   0.545  0.282  Mets
 9  4   198   0.559  0.278  Braves
 8  5   327   0.529  0.248  Blue Jays, Twins
 8  6   368   0.528  0.209  Reds, Padres
 6  4   416   0.526  0.207  Indians
 7  5   393   0.521  0.201  Red Sox
 9  6   312   0.529  0.196  Tigers, Diamondbacks
 5  4   493   0.520  0.185  Mariners
 7  6   403   0.514  0.154  Brewers
 7  7   359   0.504  0.131  Orioles, A's
 6  6   425   0.503  0.118  Yankees, Astros,Pirates
 6  7   362   0.490  0.099  Rangers,Marlins, Cardinals
 5  7   371   0.475  0.078  White Sox
 6  8   349   0.475  0.074  Devil Rays, Angels, Rockies
 5  8   335   0.463  0.060  Cubs
 3  9   143   0.438  0.049  Phillies
 4  8   241   0.450  0.046  Giants
 4 10   149   0.438  0.040  Nationals
 4 11   110   0.428  0.027  Royals

So here we see the Dodgers at 10-4 have the highest probability of reaching the post season at 30.2% (our basic report on BP has them at 41.2%) and teams in their position have gone on to play .560 baseball over the course of the season equivalent to 91 wins. On the opposite side the Royals have a 2.7% chance of reaching the post season (BP has them at 7.8% which seems extraordinarily high to me) and teams have come in at 69 wins (.428).

But of course this technique doesn't take into consideration the fact that more teams reach the playoffs given the current format. The following table takes this into account by looking only at seasons since 1995 when the three division format and wild card were introduced.

 W L Teams Final PctPSPct Teams
 9 4   25  0.555   0.480  Braves
10 4   23  0.545   0.435  Dodgers
 8 4   49  0.544   0.429  Mets
 8 5   66  0.530   0.394  Blue Jays, Twins
 9 6   58  0.529   0.379  Tigers, Diamondbacks
 8 6   66  0.523   0.364  Reds, Padres
 7 5   70  0.515   0.357  Red Sox
 5 4   84  0.519   0.345  Mariners
 6 4   68  0.520   0.338  Indians
 7 7   65  0.500   0.292  Orioles, A's
 7 6   65  0.501   0.262  Brewers
 6 7   70  0.496   0.243  Rangers,Marlins, Cardinals
 6 6   75  0.503   0.227  Yankees, Astros,Pirates
 5 7   56  0.476   0.179  White Sox
 5 8   54  0.480   0.167  Cubs
 6 8   64  0.481   0.156  Devil Rays, Angels, Rockies
 4 8   44  0.465   0.136  Giants
 4 11  20  0.446   0.100  Royals
 4 10  24  0.447   0.083  Nationals
 3 9   20  0.448   0.050  Phillies

The smaller sample here illogically puts the Braves at 9-4 ahead of the Dodgers at 10-4, but as you can see the odds of those teams reaching the post season goes up quite a bit since approximately 28% of all teams have made the playoffs since 1995.

Mostly what this tells us is that it is a long season and unless your team is 4-11, 4-10, or 3-9, based on history they still have a chance to make some noise.