NoahChain football ranking system

NoahChain




A pair-wise ranking system for college football teams



There are five steps to this method



The brief explanation



1. Count chains of wins and losses between each pair of teams.

For example consider the following chains which link team A and B



A beats B, Primary Win for A

A beats C who beats B, Secondary Win for A

A beats E who beats F who beats B, Third level win for A

B beats G who beats A Secondary Loss for A



2. Convert secondary and third level and higher level wins and losses to the equivalent number of primary wins and losses. This is based on the probability that each chain represents team A being higher ranked than team B. This requires a parameter “H” which is the probability of the winner of a single game is higher ranked than the loser. This parameter “H” is the key to this ranking system. H is usually around 80%



3. Calculate the likelihood of team A being better than team B This is based on the number of equivalent victories and losses between the two teams.



4. Determine the average likelihood that team A is better than a random team. This is simply the average of the likelihood of team A being better than the other teams. Repeat this for all teams and then rank all teams on this basis.



5. Iterate the expected win percentage until it stabilises. Alter the percentage of games higher ranking teams are expected to win (parameter “H”) until the value equals the actual percentage of games won by the higher ranked team in that season.



For a more detailed explanation see this google doc link https://docs.google.com/document/edit?id=1dePOpGFRW6BqZQIHLLf1J_mOvZci1_F1K1hb-C5Li34&hl=en#

I hope to have this accepted onto the Massey ranking websites once the 2010 season starts.

It is called NoahChain because it compares teams two by two  and looks at chains of victories and defeats.