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From: djb@cbosgd.UUCP
Newsgroups: net.sport.football
Subject: Mathematical ranking methods
Message-ID: <513@cbosgd.UUCP>
Date: Wed, 2-Nov-83 07:16:40 EST
Article-I.D.: cbosgd.513
Posted: Wed Nov  2 07:16:40 1983
Date-Received: Sun, 6-Nov-83 03:59:22 EST
Organization: AT&T Bell Laboratories, Columbus
Lines: 33

About once per week USA TODAY publishes a ranking of college football
teams done according to a mathematical algorithm developed by a
mathematics professor at Penn State.  According to the blurb printed
along with the ratings, the algorithm gives a team one point for each 
win and one-half for a tie, compares schedules (somehow) and produces a
logarithmic power indicator (0.00 being a super-team, with values of around
12.00 for the weakest teams).  In addition, the method allows extrapolation
of what the outcomes would be if all the listed teams played each other.
This metric is expressed in terms of the percentage of games each team
would win.  Teams are ranked according to their power factor.  The current
standings are quite interesting, with several notable differences between
power ratings and the coaches/wire-services poll.

My question is, does anyone know how this algorithm or others similar
to it are implemented?  The idea seems to be to derive a mathematical
way of characterizing the toughness of a team's schedule, with some
weighting factors for individual game outcome.  (If you lose to a tough team,
you don't get penalized as much as if you lose to a weaker team.  Conversely,
if you beat a tough team you get more than if you beat a weaker team.)
The logic is basically obvious, but the translation into mathematical
terms seems considerably less clear.

I would like to have some crafty scheme to rank teams analytically,
even if it does oversimplify in places.  If I can't find out how the
existing ones work, I'll take reasonable suggestions on how to develop
one myself.

	David Bryant   Bell Labs   Columbus, OH   (614) 860-4516
	(cbosg!djb)

ps: Any of you folks from Penn. State out there?  I can dig up the
    name of the professor there (as I remember, his last name starts
    with a 'J') if it'll help.