Thursday, February 24, 2011
How many teams in MLB playoffs? Part 2
All data is from Stanley Cup seasons 1987-2010, when the NHL had 4 rounds of best-of-7. Excluded is the 1995 Cup 48-game season (and naturally the lockout year). That gives us 22 Stanley Cups.
In each season, I ranked the teams by points (1 through 30). In all 22 seasons, the Stanley Cup was won by a team that finished in the top 8 in the standings. The team that led the league in points won 7 of the 22 Cups, or 31.8%.
Let’s focus on the teams that led the league. Here’s how many rounds they won:
4: 7 times (and won the Cup)
3: 1 times (lost in Finals)
2: 5 times (lost in Final 4)
1: 4 times (lost in Final 8)
0: 5 times (eliminated first round)
Boring stuff to skip
Suppose the #1 team has a 75.1% chance of winning each series. The chance of them winning 4 consecutive series is 75.1% ^ 4 = 31.8%. So, given 22 seasons, we’d expect 7 Stanley Cups, just like it really happened.
The #1 team made the Cup finals 8 of 22 seasons (or 36.4%). In order for that to happen, they’d have to have a chance of winning each series 71.4%.
The #1 team reached the Final Four 13 of 22 seasons (or 59.1%). In order for that to happen, they’d win each series 83.9% of the time.
The #1 team won at least one series 17 of 22 seasons (or 77.3%). That is its chance of winning that first series.
Putting it together, the #1 team has around a 77% of winning each series.
A three-round Cup run
If the NHL was down to a 3-series Cup run (8 teams, or 12 teams with byes for the top 4), the #1 team would need to win 3 series of 4-of-7. That would imply they’d win the Cup .77^3 = 46% of the time according to the boring stuff above.
An alternative way to look at it is that the 17 times that the #1 team entered the playoffs in the Final 8 round, they won 7 times. 7/17 = 41%.
Conclusion
An NHL fan is suggesting that the #1 team should win the Cup 32% of the time if they want a 16-team playoffs, and 41% of the time if they want an 8- or 12-team playoffs.
My question: how many MLB teams would you need in the playoffs in order to get a 32% or 41% chance of the #1 team in MLB of winning the World Series? How many in the NBA? The NFL?
Who wants to do the legwork on presenting the matching data for these sports?


I think I remember reading that Tiger Woods won one-third of his tournaments at his peak?
How often did Federer and Nadal and Sampras win?
Is it fair to say that we want the #1 team to win about one-third of the time?