NCAA POWER INDEX CALCULATION METHOD

Overview - "the quick version"

The NCAA Power Index (NPI) is a method the NCAA has developed to rank teams for determining at-large qualifiers for its Division II and III championship tournaments. Currently, it is also used as a replacement for the old "Pairwise" method in determining teams for the Division I men's and women's ice hockey championships.
The method takes into account win/loss records, which themselves are adjusted for home advantage (so an away win may be counted more than a neutral win, which in turn may be counted more than a home win), strength of schedule, and "quality wins."

The Dials

There are a number of settings, or "dials," which presumably get their name from the fact that you can "turn each dial" to change that setting, used in NPI:

Record/Strength of Schedule (SOS) - this determines how much of the rating is based on wins and losses, and how much on SOS, which is the ratings of the team's opponents. Note that the sum of these values is 100 (e.g. 25/75, or (100 x 1/3)/(100 x 2/3)).
Home/Away - if a neutral site win counts as 1 win, how much should a win at home, or an away win, count? If there is no home advantage, then these are both set to 1; otherwise, the home value is set to a value less than 1, and the away value is 2 minus the home value (e.g. 0.9/1.1, or 0.8/1.2).
Overtime Win/Loss - should an overtime win count the same as a win in regulation, and if not, how much of a win (and how much of a loss) should an overtime win be worth? For example, if the dial is 80/20, then an overtime win is counted as 0.8 of a win and 0.2 of a loss to the winner, and 0.2 of a win and 0.8 of a loss to the loser.
Note that this is combined with home/away; for example, if home/away is 0.9/1.1 and overtime is 0.8/1.2, then a home win, which is normally worth 0.9 wins to the winner and 0.9 losses to the loser, is treated as 0.8 of a home win and 0.2 of a home loss, which is 0.9 x 0.8 = 0.72 wins and 0.1 x 1.2 = 0.12 losses for the winning (home) team, and, correspondingly, 0.12 wins and 0.72 losses to the losing (away) team.
NOTE: For whatever reason, Division I ice hockey does not calculate it this way. It uses home/away of 0.9/1.1 and overtime win/loss of 60/40, but the "overtime portion" is not subject to home/away adjustment; as a result, a home win counts as (0.9 x 0.4 + (0.6 - 0.4)) = 0.56 wins and (1.1 x 0.4) = 0.44 losses, and an away win counts as (1.1 x 0.4 + (0.6 - 0.4)) = 0.64 wins and (0.9 x 0.4) = 0.36 losses.
Quality Win Minimum Rating/Multiplier - a win against a team with an NPI greater than the Quality Win Minimum Rating dial receives a bonus for that game, which is calculated as the amount by which the opponent's NPI exceeds the Minimum Rating Dial, multiplied by the Multiplier dial. For example, if the Minimum Rating value is 54 and the Multiplier value is 0.5, then a win against a team with an NPI of 56.2 receives a bonus of (56.2 - 54) x 0.5 = 1.1.
Minimum Wins - this is not the minimum number of wins a team needs to be ranked. Normally, a win will not be included in that team's NPI calculation if the opponent had such a low rating that it would cause the team's NPI to go down. However, there must be a certain number of wins included in the calculation, as indicated by this dial. Note that it is possible to count a win partially; if, for example, the Minimum Wins setting is 5, the team has already counted 4.4 wins in its calculation, and the next win has a weight of 0.9, then only (5 - 4.4) / 0.9 = 2/3 of that game would be included in the calculation.
Note that if a team has fewer wins then the Minimum Wins value, then all of its wins will be included.

Note that some of the dials can have conditions on their use. For example, in Division III in 2025-26, in ice hockey, only regular season games are subject to the overtime adjustment (this is because regular season ice hockey overtime is 3-on-3, while postseason is full-strength), and in men's basketball, the home/away values are different for conference and nonconference games.
Also, as an example, football overtime could be applied only if a game went into a third overtime (where "dueling two-point conversions" start), or softball overtime only if the game went into the tenth inning (when every half-inning starts with a runner on second base).

Next - Step 1 - Determine Game Values

Acknowledgements

Document produced by Don Del Grande (email don.p.del.grande@gmail.com).
If you notice any problems with the method, or the document in general, feel free to email me.

Thanks to:

The NCAA, especially J.P. Williams and Kevin Alcox, for providing information on the NCAA Power Index, including the dial values for Division III sports as well as Division I ice hockey, and for providing NPI values used to verify my numbers.
Ken Massey, for maintaining results information for a number of sports, which was useful in confirming the calculations.
USCHO.com, for providing information on men's ice hockey, including Division I and III results.
College Hockey News, for providing additional information on the Division I ice hockey overtime calculation method.