How are Women’s Basketball Teams Ranked?
March 28, 2018
Last weekend, the Mercer Bears faced off against the Georgia Bulldogs in the first round of the Women’s NCAA Basketball Tournament. The Bears had a season record of 30-3, while the the Bulldogs had a record of 26-6. Judging solely on the season records of the two teams, one would assume that the Bears had a higher ranking, but that was not the case. Leading up to the game, Mercer was ranked 13 and Georgia was ranked 4. So what exactly goes into determining NCAA rankings?
The NCAA Basketball Committee uses a Rating Percentage Index or RPI to determine team rankings.
The formula is as follows:
RPI = (WP ✕ 0.25) + (OWP ✕ 0.50) + (OOWP ✕ 0.25)
WP = Winning Percentage
OWP = Opponents’ Winning Percentage
OOWP = Opponents’ Opponents’ Winning Percentage
Based on the formula, team records only account for 25 percent of their ranking. The portion that weighs the most in rankings is the winning percentage of the team’s opponents. In other words, how tough is the team’s schedule. Georgia competed against tougher teams than Mercer. Their opponents had a higher winning percentage than Mercer’s opponents. Because this accounts for 50 percent of the ranking, this is the primary reason the Mercer Bears were ranked lower than the Georgia Bulldogs, despite Mercer’s better record.
The graph gives the data for two hypothetical teams. Team 1 has a better record than Team 2, but Team 2 has tough opponents than Team 1. For the purposes of the example, the Winning Percentage of the Opponents’ Opponents’ is the same for each team.
The calculations for the RPIs are as follows:
Team 1 = (4 ✕ 0.25) + (2 ✕ 0.50) + (3 ✕ 0.25) = 2.75
Team 2 = (2 ✕ 0.25) + (4 ✕ 0.50) + (3 ✕ 0.25) = 3.25
Although Team 1 had a higher winning percentage, Team 2 had a tougher schedule. This resulted in Team 2 being ranked higher than Team 1. This is why Mercer was ranked lower than Georgia.