Rankings 101

Which team is the best?

How much better is this team than that team?

It's all a matter of either opinion or statistics.

Opinion

Informed opinions for Division I Women's Basketball are expressed in these two weekly polls that rank the top 25 teams:

AP Top 25

The rankings are compiled by polling 40 sports writers or broadcasters across the nation. These are the 2011-12 season voters.

ESPN/USA Today Coaches

The rankings are compiled by polling 31 voters, all head coaches at Division I institutions and members of the WBCA (Women's Basketball Coaches Association). There is one coach from each conference that has at least eight teams. June Daugherty from Washington State is the Pac-12 voter this season. These are the 2011-12 season voters.

When you read, for example, that Stanford is ranked 3/5, it means that Stanford is No. 3 in the AP Top 25 Poll and No. 5 in the ESPN/USA Today Coaches Poll.

These rankings are just a popular way of evaluating teams. They are not a factor in selecting teams for conference or national post-season tournaments.

Statistics, Winning Percentage

Each conference ranks its members by their winning percentage (games won divided by games played). Once conference play has begun, the teams are ranked by their overall percentage within conference percentage. These are the current Pac-12 Standings

The standings are used as seedings for the conference tournament.

Statistics, RPI

The RPI (Rating Percentage Index) is a measure of strength of schedule and how a team does against that schedule, as well as its winning percentage. It is used by the NCAA as one of their factors in deciding which teams to invite to the NCAA tournament and where to seed them.

The formula for the RPI is:
RPI = ((0.25 * WP) + (0.50 * OWP) + (0.25 *OOWP)), where:

WP

is the team's weighted winning percentage against Division I opponents. Games against non-Division I opponents are not included in the RPI calculation.

The calculation of the winning percentage for RPI purposes is changed this season (as it was for the men in 2004-05) to give more weight to road wins vs. home wins. A team's win total = ((1.4 * road wins) +( 0.6 * home wins) + (1.0 * neutral site wins)).

OWP

is the team's opponents' non-weighted winning percentage, excluding results against the team in question. It is also called the team's schedule strength.

OOWP

is the team's opponents' opponents' non-weighted winning percentage, or the team's opponents' schedule strength, excluding results against the team in question.

The RPI and Schedule Strength of the 342 Division I Women's Basketball teams are available on the internet from these organizations:

• NCAA, updated weekly on Monday morning, beginning in late December.
• Collegiate Basketball News, updated weekly on Monday morning.
• Real Time Sports Ranking, updated daily.
• Warren Nolan, updated daily.

The rankings from these organizations vary quite a lot, perhaps because of data errors, perhaps because of slight differences in the formulas they use. No matter — in the end, the only rankings that matter are those from the NCAA.