[ View Thread ] [ Post Response ] [ Return to Index ] [ Read Prev Msg ] [ Read Next Msg ]

MLB Forum

Schedule correlation effect

Posted By: James
Date: 28 Aug 01, 3:08 pm

This is a followup to Colin's season simulation thread below.

Colin had estimated each team's chance of making the playoffs by simulating the remaining season, basically flipping a coin for each team's remaining games. (He ran two simulations, one flipping fair coins, and the second flipping biased coins to incorporate his power ratings.)

This ignores the anti-correlation between competing team's records caused when they play each other. For example, at the very end of the season, the Dodgers and Arizona play 3 games, and obviously they can not both win 3 games. This effect becomes larger as the season gets shorter because the common games become a larger fraction of the total games played.

I just ran a quick test to see how large this effect might be.

Currently the NL West standings are:

Arizona 75 55
SF 73 58
LA 72 59

I did not include any power ratings, assigning each team a 50% chance of winning all their remaing games.

Using Colin's original approach, flipping 32 coins for Arizona, 31 for SF, and 31 for LA, I got the following probabilities of each team winning the NL west:

Arizona 65%
SF 22%
LA 13%

I then modified this to take into account the common games, for example 7 of the coins flipped for Arizona were also used for the Dodgers (so LA wins when Arizona loses). The new playoff probabilites are:

Arizona 62%
SF 23%
LA 15%

So it looks like this is not a very big effect yet with 30 games left in the season.

The probabilities above are intended only as investigations of simulation methodology, and not meant to be predictions of the final NL West results.

Password:

Messages In This Thread

Schedule correlation effect -- James -- 28 Aug 01, 3:08 pm
Effect is a little bigger than I expected -- Colin Caster -- 28 Aug 01, 6:01 pm
Sim size -- James -- 28 Aug 01, 11:19 pm
Value of a game -- James -- 31 Aug 01, 11:11 am
Nice analysis -- thanks. (nt) -- Colin Caster -- 31 Aug 01, 12:14 pm

 


Post Response
Your Name:
Your E-Mail Address:
Subject:
Picks Post?
Message:

If you'd like to include a link to another page with your message,
please provide both the URL address and the title of the page:

Optional Link URL:
Optional Link Title:

If you'd like to have the option of deleting your post later,
please provide a password (CASE SENSITIVE!):

Password:

If you'd like e-mail notification of responses, please check this box:

 

 

[ View Thread ] [ Post Response ] [ Return to Index ] [ Read Prev Msg ] [ Read Next Msg ]

MLB Forum is maintained by Pi Yee Press