NCAA Basketball Tournament Selection Process - Seeding

Seeding

The selection committee's work to seed the teams is just as vital as their work to select the at-large teams. While the selection process starts before the seeding process, the two often overlap; with conference tournaments not finishing until Selection Sunday itself, and only one hour between the end of the last game (usually the Big Ten Tournament championship game) before the brackets are officially unveiled, the committee cannot wait until after all the games are played to start determining the seeds. While nothing is set in stone until after all the games are played and the brackets are established, the committee may have a good idea of where a team is and where they could rise or fall depending on their showing in the later stages of their conference tournament. The women's tournament has the luxury of an extra day from the end of games on Sunday to prepare its bracket announcements on Monday.

Though the brackets only feature the seed numbers 1-16 in each region, the committee assembles an S-curve of teams seeded from 1-64. In theory, the teams 1-4 on the seed list will all be #1 seeds (the #1 "seed line"), 5-8 will be #2 seeds (the #2 seed line), and so on; however, bracketing rules often lead to some deviation from this. The S-curve is most important for keeping each region balanced, the ideal being that each region will be equally strong. For example, the committee will try to ensure that the number 1 team on the seed list, the national #1 seed, will be in the same region as the weakest #2 seed. The committee tries to ensure that the top four seeds in each region are comparable to the top four teams in every other region. For example, if one region has the best #1 seed (#1 overall), the weakest #2 seed (#8 overall), the best #3 seed (#9 overall), and the weakest #4 seed (#16 overall), its seeds add up to 34, the ideal number. But if a region has the best team for every given seed, its seeds would add up to 28, and a region with the weakest team in every seed would add up to 40, making the two regions very unbalanced. It is extremely unusual that an at-large bid can be lower than a #12 seed, but it has occurred, most recently with Bradley and Air Force being #13 seeds in the 2006 Tournament. While the seeds are almost never perfectly balanced throughout the four regions, the committee strives to ensure that they differ from each other by only a few points. The process is identical for the women's tournament, with the exception that seeding occurs to 64.

The selection committee uses a number of factors to place teams on the S-curve, including record, strength of schedule, the Ratings Percentage Index (RPI), and a team's overall performance in recent games. The RPI rating is often considered a significant factor in selecting and seeding the final few teams in the tournament field, though the selection committee stresses that the RPI is used merely as a guideline and not as an infallible indicator of a team's worth.