Ashes Update

England won the fourth test. Our belief before then was 3:4:3.


Under the England strong model, the odds of the win were 1/2
Under the equal model, 1/3
Under the Australia strong model, 1/6.

So the numbers get multiplied by those probabilities.

3/2:4/3:3/6

or

9:8:3

We now consider England the stronger team in 9 universes out of 20.

Ours. And in 17 universes out of every 20, they probably should be.

What's our prediction for the fifth test?

Well, in 9 of the 20, England have a half chance.

In 8 of the 20, they have a 1/3 chance

In 3 out of the 20, they have a 1/6th chance

Our estimate of England's chances of winning the fifth test are:

(9/2+8/3+3/6)/20 = (27+16+3)/120 = 46/120

Slightly more than the 1/3rd we'd assign if we thought the teams were even.

We've now seen England win twice, Australia once, and we're starting to expect that trend to continue.

And of course, if they do, we'll update again!