rules
ESPN’s Bracketology efforts are focused on projecting an NCAA Tournament field just as we expect the NCAA Division I Basketball Committee to select the field in March. ESPN bracketologist Charlie Kareem uses the same data points that the committee prefers, including strength of schedule and other indicators throughout the season, including network data and team sheet data similar to what is available to the NCAA, in his field projections. Visit the NCAA website for a fuller understanding of NCAA selection criteria.
64-Team bracket
The 64-team bracket is the standard version of the NCAA Tournament field that has been in place since 1994. If the 2021 field is made up of 64 teams, there will be some key differences from years past.
The main adjustment from a regular year is of course playing the entire NCAA Tournament at one site. This eliminates the need for geographical considerations in sowing. Additionally, there will be at least one fewer automatic qualifiers this season, as the Ivy League’s decision to forgo the 2020-21 season reduced the number of AQ entries to 31 for the season.
48-Team bracket
In this projection, the condensed selection process would reduce the field by eight at-large teams and eight automatic qualifiers (the latter still receiving a unit of revenue). The top four seeds in each region will receive a bye into the second round, with four first-round games per region – 5-versus-12, 6-versus-11, 7-versus-10, and 8-versus-9.
16-Team bracket
In this projection, the committee selects and ranks the best 16 teams available. There are no automatic playoffs, although all non-contending conference champions receive an allocated revenue unit.
To maintain some sense of national balance, conference participation was limited to four teams. No region may have more than one team from the same conference.