How are BCS ranks in NCAA football determined? Is it determined by popular vote and record?
What factors affect a ranking?
The BCS rankings are determined by averaging together two human polls and six computer rankings starting in the 8th week of the regular season. A team's ranking is determined by the following:
Harris Poll - 1/3 of the ranking is determined by the Harris Poll which is a weekly poll of 115 invited sports media members who rank the top 25 of the 120 teams in the NCAA Football Bowl Subdivision. In this poll the media assign each member of the top 25 a value from 1-25 with the top ranked team receiving the value 25. For this reason, the highest possible value that a team could receive (if voted #1 by all voters) would be 2875, so each team's overall score is divided by 2875 with the highest possible ranking being 1.00.
Coaches Poll - 1/3 of the ranking is determined by the Coaches' Poll which is a weekly poll of 59 coaches in the NCAA Football Bowl Subdivision. It is important to note here that most coaches are unable to watch all the teams play each week and will typically have the Sports Information Director at the school create the rankings on their behalf. The same values are applied to each team here as in the Harris Poll, except the highest possible value is 1475 instead of 2875.
Computer Rankings - 1/3 of the ranking is determined by the average of six computer rankings. The six computer rankings are Anderson & Hester, Richard Billingsley, Colley Matrix, Kenneth Massey, Jeff Sagarin and Peter Wolfe. Each computer ranking uses a different formula to rank the teams based on factors like wins, losses and strength of schedule with the highest possible score for a team being 1.00 just like in the human polls. The individual formulas used are largely unknown, but it should be noted that starting in 2004 the BCS prohibited the computer rankings from including margin of victory in their calculation. Since the formulas differ so much (some give more weight to the value of a conference win compared to a non-conference win, for example) the highest and lowest rankings received by the computers for a given team are not used to calculate this average.
These three pieces are then averaged together to create the BCS rankings for the top 25 teams in the NCAA FBS and the teams are ranked in reverse order based on their average score.