Mathematics Of Football Upsets

[Almighty Colin]

This is pretty interesting if you follow the point spreads or participate in the pools. The chances of an upset in a game fall exponentially as the point spread increases.

Here is a table that demonstrates the likelihood of an upset.

Points Upset%
1 47%
2 44%
3 42%
4 39%
5 35%
6 33%
7 31%
8 28%
9 26%
10 24%
11 21%
12 19%
13 18%
14 16%
21 6.7%
28 2.3%

A 7 point underdog wins 31% of the time.
A 14 point underdog wins 16% of the time.
A 21 point underdog wins 6.7% of the time.
A 28 point undersog wins 2.3% of the time.

You can see the effect of doubling the spread from 7 to 14 decreases by about 1/2 the chance of an upset. It decreases by about another 1/2 when the spread goes from 14 to 21.