URL for this frameset: http://www.elynah.com/tbrw/tbrw.cgi?1998/pairwise.shtml
In this enlightened age, the NCAA Division I hockey tournament is seeded largely by statistical analysis. So in principle college hockey fans should be able to predict on their own how the tournament will be seeded in advance. Problem is, the selection process has been changing slightly every year, and in the past it's been difficult to find out the current rules in advance. After the tournament pairings were announced last March, Selection Committee chair Joe Marsh provided a detailed explanation of how it was done to Adam Wodon of US College Hockey Online, a web site devoted to college hockey. And the NCAA Division I Men's Ice Hockey Committee decided in July to retain the selection criteria from last year. Thus, with the occasional inquiry to the NCAA for fine-tuning, we are able to say with some confidence how things will be done this year.
First of all, from the NCAA's point of view, only official games played between established programs with 20 games against Division I teams on their schedule count towards the selection process. This season those teams are all the members of the WCHA, CCHA, ECAC and Hockey East, plus Independents Army in the East and Air Force and Mankato State in the West. Exhibition games, and games against Canadian or Division II or III teams are irrelevant. Games against Division I teams not playing a full Division I schedule, such as Niagara and Holy Cross, or the "developing program" Nebraska-Omaha, in its first year of NCAA operation, do not contribute to any of the selection criteria, although they can count towards the 20 games to qualify a team for the tournament. (the fine print)
The underlying principle behind the current selection process is the pairwise comparison. One team is compared to another team based on five criteria:
A team wins one point towards the comparison for each of the first four criteria, and one point for each head-to-head game in which they defeated the other team in the comparison. Whichever team gets more points wins the comparison, and if it's a tie, the team with the higher RPI wins.
Every Team Under Consideration is compared to every other TUC in this way. The total number of such comparisons won is called the Pairwise Rating (PWR). (The current PWR is also available on USCHO.) This number can be used to rank the TUC, and in the past it was believed that the teams were seeded in the order of these Pairwise Rankings, but that is not precisely how it's done. The PWR is used to get a rough sense of which teams are in contention for which spots, but then those teams are placed according to the pairwise comparisons among or between them. For example, if you're battling it out for the twelfth and final spot in the postseason, it doesn't matter how you compare with the fifth-rated team. Thus a two-way tie is impossible, since one team will always win the pairwise comparison. If three teams end up in an unresolvable tie (rock-scissors-paper), we go to the RPI to resolve the deadlock.
The NCAA tournament consists of twelve teams, divided for the first round and a half into two regionals, East and West. In each regional, two teams receive first-round byes while the other four play on the first night. On the second night of the regional, the two bye teams play the two first-round winners, with the two survivors from each regional then advancing to the national semifinals the following weekend. The selection and seeding process can be divided into the following steps:
The regular season (the fine print) and tournament champions in each of the four conferences receive automatic berths, which accounts for between four and eight of the twelve teams. The remaining four to eight at-large teams are selected according to the pairwise method. There is the one stipulation that each conference must have at least two representatives in the tourney.
Here's how the procedure was actually applied to seed the 1998 tournament, and here's a summary of how it's gone for the last three years. To follow through the procedure yourself, try this script.