Tuesday, December 27, 2011

Regular Season Records Say Nothing About Post-Season Success

I often hear fans say something along the lines of: "The Tigers are good enough to get into the playoffs, but they don't have enough to win the World Series."  This suggests that the Tigers might have enough talent to win 90 games and a division title, but are not strong enough to beat a stronger team from another division.  Recent history has shown, however, that it doesn't take a dominant team to win the World Series.

Two examples of teams with modest regular-season success winning the World series happened the last two times the Tigers were involved in the playoffs.  When the 95-win Tigers won the American League pennant in 2006, they went on to lose the World Series to the Cardinals, a team which won just 83 games during the regular season.

This past season, the Cardinals miraculously seized the wild card spot on the last day of the season with 90 wins.  The Red Birds proceeded to eliminate the Phillies (winners of 102 regular season games) and eventually won the World Series again.

Despite the examples above, one would think that the most dominant regular-season teams would win most often in the post-season.  To test this theory, I looked at every playoff team since 1996.  This includes all years since the expanded playoffs began except the strike-shortened 1994 and 1995 seasons.

The results of all 128 playoff teams between 1997-2011 are shown in Table 1 below.  The ninth row of the table is read as follows: There were 12 playoff teams with 90 wins during the season, four got past the divisional series, three won the pennant and one was the world champion.  The tables tell us that the regular-season win totals of the 16 world champions were: 83, 87, 90, 91, 92, 92, 92, 92, 92, 96, 98, 98, 99, 99, 103, 114.  Just looking at the win totals of the World Series winners makes it appear as if their not a strong association between winning in the regular season and winning the World Series.

An examination of the divisional series and pennant columns reveals a similar story.  In fact, the correlation between regular season wins and post-season success is only 0.11 and is statistically insignificant.  In other words, how often a team wins in the regular season tells us nothing about what they will do during the playoffs.

Table 1: Post-Season Performance by Regular Season Win Totals

Regular Season Wins
Teams
Divisional Series
Pennant
World Series
82
1
0
0
0
83
1
1
1
1
84
2
1
0
0
85
1
0
0
0
86
1
1
1
0
87
2
1
1
1
88
7
4
0
0
89
4
2
1
0
90
12
4
3
1
91
9
2
1
1
92
10
6
5
5
93
5
2
1
0
94
7
3
1
0
95
16
10
3
0
96
10
5
3
1
97
12
6
1
0
98
5
4
3
2
99
3
2
2
2
100
4
1
0
0
101
5
3
1
0
102
3
0
0
0
103
4
2
2
1
105
1
1
1
0
106
1
1
0
0
114
1
1
1
1
116
1
1
0
0
Totals
128
64
32
16

Data from Baseball1.com

To illustrate the above correlation (or lack thereof) more clearly, regular-season win totals can be divided into categories: < 90 wins, 90-94, 95-99, 100+.  Table 2 below shows the data for all 128 playoff teams.  The first row is read as: 19 teams with less than 90 wins, 10 (53%) took the divisional series, four (21%) won the pennant and two (11%) were world champions.

You can see that the percentages don't change very much as you move up the ladder from teams with fewer than 90 wins to 100-plus-win teams. The results in row are fairly close to what you would expect if every series were a coin flip: 50% chance of winning the divisional series, 25% chance of winning the pennant and 12.5% chance of winning the World Series.

Table 2: Post-Season Performance by Regular Season Wins Category

Regular
Season
 Wins
Teams
Divisional Series
Pennant
World Series
< 90
19
10 (53%)
4 (21%)
2 (11%)
90-94
43
17 (40%)
11 (26%)
7 (16%)
95-99
46
27 (59%)
12 (26%)
5 (11%)
100+
20
10 (50%)
5 (25%)
2 (10%)
Data from Baseball1.com

Post-season success is looking even more random than I expected, but let's do one more thing.  Instead of just taking win totals across seasons, we can rank the post-season teams within each season. For example, the following ranks would be assigned to NL teams in 2011: (1) Phillies 102 wins, (2) Brewers 96, (3) DiamondBacks 94, (4) Cardinals 90.  

The results for all years are shown in Table 3 below.  The first row reads as follows: There were 36 teams ranked first in wins (including ties), 21 (58%) took their divisional series, 10 (28%) won the pennant and 5 (14%) were world champions.  As in Table 2 above, there is not a lot of variation from row to row.  The bottom ranked teams are as about as likely to win post-season as the top ranked teams. Again, the results are similar to what you would see if the series were determined by coin flips. 


Table 3: Post-Season Performance by Regular Season Rank

Regular
Season
Rank
Teams
Divisional Series
Pennant
World Series
First
36
21 (58%)
10 (28%)
5 (14%)
Second
32
14 (44%)
8 (25%
5 (16%)
Third
33
13 (39%)
7 (21%)
3 (9%)
Fourth
27
16 (59%)
7 (26%)
3 (11%)

Data from Baseball1.com
 

So, it seems clear that regular-season win totals give us no indication of what to expect in the playoffs.  That's not to say that the playoffs are a total crapshoot and that there is no difference between a World Series contending team and a playoff-contending team that doesn't win the World Series.  It's entirely possible that certain types of teams have a greater likelihood of success in the playoffs regardless of win totals.  Perhaps, teams with very wide run differentials (more so than their wins would indicate) or teams with strong pitching or any number of other types of teams have a greater likelihood of success in post-season.  I'll explore some of those possibilities in the future.

Still, the total lack of correlation between regular-season wins and playoff wins is pretty remarkable.

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