The Playoff Season Part 1

This is the first of a multi part series describing the playoff season which can be very different from the regular season.   Mediocre players become superstars and superstars can play mediocre in the playoff season.

This data model treats all playoff games from 1903 – present as a single season.  This creates a large pool of playoff data to draw averages from.  We treat all playoff games as of equal stature.  There are many more playoff games in the modern era so guys like Babe Ruth and Lou Gehrig will suffer but that’s just how it has to be.   This data pool is still very small even with all playoff games.

In part 1 we’ll illustrate the size of this pool by showing a deltaWAA lookup table we compiled for regular season.  The regular season from 1970-present consisted of 86,000 games.  There are only 1500 playoff games for the playoff season dataset.

Here is the deltaWAA table for playoffs from 1903-2016.  DeltaWAA is the win/loss record from the regular season.

Category # Games Total % Home % Away %
1-3 271 0.531 0.527 0.536
4-6 213 0.526 0.555 0.495
7-9 183 0.541 0.552 0.531
10-12 156 0.564 0.543 0.594
13-15 137 0.474 0.487 0.459
16-18 88 0.523 0.533 0.512
19-21 71 0.380 0.385 0.375
22-24 58 0.466 0.417 0.545
25-27 38 0.579 0.636 0.500
28-30 24 0.708 0.786 0.600
31-33 28 0.464 0.231 0.667
34-36 16 0.312 0.500 0.000
37-39 10 0.500 0.833 0.000
40-42 20 0.600 0.538 0.714
43-45 7 0.714 0.667 0.750
46-inf 159 0.516 0.511 0.521

The number of games tapers off as the difference in win/loss records (deltaWAA) increases which should be expected.  When we get into very low number of games outliers are going to affect the measured win%.  The three total win% highlighted in tan show a wide variation.  Obviously a team who is 35 wins ahead of its opponent isn’t at a 0.312 disadvantage.   Outliers are a problem with not much data so let’s consolidate.

Below is a consolidated version of the above table creating larger sets of games.

Category # Games Total %
1-9 667 0.532
10-21 452 0.500
22-inf 360 0.522

What does this table tell us?  Not sure.  Between 10-21 the win% drops to even steven which doesn’t make sense.  The 22 – infinity category is almost the same as the 1-9 category.  This may indicate that regular season win/loss records may slightly increase win%, perhaps 0.52 – 0.53, but it remains constant with deltaWAA.   This means, on average, the  team with the best record in MLB only has a slight advantage over the  team with the worst record in MLB during the playoff season according to the compilation of all historical playoff game results.

A slight advantage is better than no advantage.  During the regular season our lineup-pitcher combo tables seemed secondary to the deltaWAA table.  According to the above findings, the opposite may be true in the playoffs.

We’ll pursue this more later.  Lineup/pitcher combo tables part 3 coming.  Until then….