Saturday, October 1, 2011

MLB Post Season: RedSox out, Rays in

Last Wednesday was surely a crazy day for baseball. It looked like the RedSox had a post season birth all sewn up, but it wasn't to be with the Rays coming back to win from 0-7 in the 8th innings and the RedSox blowing the game needing only one more strike in the 9th.

Yahoo have quoted the chance of the Rays making the playoffs as 1 in 278 million. They don't say from what position (ie mid year, Monday night, Tuesday night, etc). They do rely on (in their words), 'noted statistician Nate Silver' who provided the odds from a NYTimes blog. Here is the maths behind his estimate ...

The following is not mathematically rigorous, since the events of yesterday evening were contingent upon one another in various ways. But just for fun, let’s put all of them together in sequence:

  1. The Red Sox had just a 0.3 percent chance of failing to make the playoffs on Sept. 3.
  2. The Rays had just a 0.3 percent chance of coming back after trailing 7-0 with two innings to play.
  3. The Red Sox had only about a 2 percent chance of losing their game against Baltimore, when the Orioles were down to their last strike.
  4. The Rays had about a 2 percent chance of winning in the bottom of the 9th, with Johnson also down to his last strike.
If you read the NY Blog or the Yahoo comments, there are a number of people who rip into this maths as wrong ... just plan wrong. Firstly, he says that the chance of the RedSox not making the playoffs is 0.3% (3 in 1000) ... but then a few lines later, he says it is 1 in 278 million. Secondly, #1 and #2, #3 or #4 are not independent. #2 thru #4 are how #1 occurred. Thirdly, #2 and #4 are also not independent.

I am sure that Nate Silver knew or was aware of this ... however, Yahoo picked it up and has been repeating it as the truth ever since ... even after their first story on it got ripped in the comments.

For my take, the RedSox melting down was pretty unlikely, but it has happened before (mets a few years ago, Atlanta Braves this year) ... 3 in 1000 sounds a little low to me. Closes blowing saves (even Bapelbon ... gee, when was the last time he blew a save? Oh ... 8 days before this one on 9/20). Teams escape from losing even when they are down to their last strike (it happened twice on Wednesday night ... Rays and RedSox!).

Before the games started on Wednesday, I would have put the RedSox at a 60/40 to go through - they are playing a poor team while the Rays were playing a good team (but that team was resting its best players). Sure, I would have lengthened the odds when the Rays went down 7-0, but not out to 1 in 10,000 and certainly not to 1 in 278m.

To me, the most amazing thing in this situation was that I could switch between the RedSox game (see them lose), flip over to the Rays game and see the crowd react to the news and then (a few minutes later) see the Rays win.

1 comment:

  1. I was just watching the defensive highlights on MLB.com and saw the Os get a double play off a very slow roller (that must be about a 5% chance) and then throw a RedSox runner out at the plate (another 5% chance) ... that blows the 1 in 278m out a few more decimal places .

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