Bobo the Monkey

Posted on 10/07/2010 by


Once in a while, I like to take a look at incoming links for the site and go off to visit far away forums to see what they’re saying about what I write.


Courtesy of


This can be a very rewarding and frustrating experience. Rewarding in that you get to see what the great zeitgeist of the internet spits out when you feed it an idea. Frustrating because well, it’s the internet.


Always remember 1990


As an old grizzled veteran of the boards, I have to fight my natural instinct to fight back, feed the trolls and contribute to kitten cruelty.
But a comment I read somewhere in the great wilds of the net has inspired a response. The gist of the comment was that the Wins Produced model (see here for detail) was as accurate as just using games won last season. Rather than give the typical internet reaction:

I decided to break out the excel. I was reminded of a post that was shared with me by a certain svengali like presence in my life that has me in his thrall. The piece is from advanced nfl statistics and in it they look at the predictions from Football Outsiders versus some very simple models (just predicting 8 wins or a basic regression to the mean model which is jokingly called Koko the Monkey). So I decided to do something similar.

Using data from 1979, my models to compare are:

  • Wins from Previous Year
  • Regression to the Mean: (Wins from LY -41)/2 +41 (or Bobo the Monkey)
  • Wins Produced

If I look at the results in terms of regression it looks like this:

The difference is stark. If I look at the average error (RMSE) it looks like:

So 94% percent correlation versus 41% percent and an RMSE of 2 versus 8 wins. Bobo the monkey indeed.


This is what we call a measured response


A final note, this blog is now the proud sponsor of a Basketball Reference player page. A No-Prize (name your own post) to whoever guesses the Player on the comments. (I will be sans internet till tomorrow night so get cracking!)

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