All season, discussion about the men’s hockey team has focused on its ranking in the national polls, which are determined by votes from various coaches and hockey journalists. Those experts made Yale the No. 1 team in the country for over two months this season. They have since dropped the Elis to No. 3, but their slight is meaningless where it matters: the NCAA tournament.

Soon after the ECAC playoffs end on March 19, the NCAA Tournament Committee will decide on and seed the field that plays for the national title. The committee will base its decisions not on its personal opinions of teams, but on a complex computer metric called the PairWise Rankings.

In those rankings, Yale remains No. 1.

Sixteen teams make the NCAA tournament. Six of those are the winners of their respective conferences’ postseason tournaments. The rest are the 10 other teams with the highest PairWise rankings. Due to its high ranking in this system, Yale is virtually guaranteed a spot in the NCAA tournament, whether it wins the ECAC playoffs or not.

PairWise is a computer system that ranks teams based on four criteria:

1) The Ranking Percentage Index (RPI): The RPI is a complicated statistic that adjusts for the strength of a team’s schedule (it’s impossible to directly compare the records of two teams that play completely different schools. Thus the RPI is used as a metric to turn those different schedules into a number that is comparable). The RPI is determined by three components: a team’s winning percentage accounts for roughly a quarter of its RPI; the average of its opponents’ winning percentages accounts for roughly a half; and the average of its opponents’ percentages accounts roughly for the last quarter.

2) Record against “Teams Under Consideration:” A Team Under Consideration is a team with an RPI above .500. Currently, 30 Division I teams are under consideration. This metric is the one that is able to cause some of the biggest sudden shifts in the PairWise rankings. If, for example, Yale has a stellar 4–0 season record against Quinnipiac, and both are under consideration, Yale will get a big boost. But if QPac’s RPI suddenly drops below .500, Yale will take a hit in the PairWise because those four wins no longer help it in this metric.

3) Record against common opponents: Since top teams from different regions — like Yale and North Dakota — rarely play each other during the regular season, record against common opponents is a useful comparison. This season, Yale is benefiting from its 5–1 rout of Colorado College in November.

4) Head to head record: If you can beat the No. 1 team in the country consistently, it’s going to look good to the computer.

Five years ago, the Yale team would not have paid any attention to the intricacies of the PairWise rankings: the team had no hopes of anything close to the NCAA tournament. Pick up the latest issue of the magazine to explore how the Elis have risen to national prominence in recent years.