The anticipation is building as the 2025 NCAA Tournament is set to begin. Fans eagerly anticipate the arrival of Selection Sunday every year in order to have the opportunity to examine their brackets and try to identify which teams are capable of making runs to the Final Four — or which top seeds could get upset on the first weekend.
March Madness could be even madder in 2025, as the college basketball season has already delivered a ton of drama. Five teams that began the year in the Top 10 of the preseason AP Top 25 poll entered the final week of the regular season unranked, including Kansas (which started out at No. 1), two-time defending national champion UConn (No. 3), tournament regular Gonzaga (No. 6) and North Carolina (No. 9).
There has been a ton of consternation about the bubble this season as well, with a very weak crop of teams vying for the final at-larges leading to increased debate about how to balance playing a tougher schedule (like the SEC’s bubblers, with Oklahoma serving as the poster child for after entering the final week of the regular season with a 4-12 mark in conference play) against a better overall record (the aforementioned North Carolina and Xavier fit this bill).
How does all of this information get weighed when it comes time to make the official bracket? Read on for a look at how the NCAA Tournament’s selection committee chooses which teams make the field and how they seed the initial bracket to create the fairest possible matchups.
How is the March Madness bracket assembled on Selection Sunday?
Every year, the NCAA Tournament selection committee is assigned with the task of selecting and bracketing the field for March Madness. Of the 68 bids up for grabs, 32 are reserved for the champions of conference tournaments, with each league's tournament champion automatically earning the right to participate in the Big Dance.
The remaining 36 slots are considered "at-large" bids that the committee hands out to, in their opinion, the best eligible teams who did not claim an automatic bid. The committee uses various criteria (such as NET Rankings, strength of schedule, quality wins, etc.) to determine which teams they feel deserve admission to the field of 68.
March Madness bracket criteria
NET ranking is a ratings tool that the NCAA created to help sort teams based on who they played, where they played them, and how they fared in those games. More weight is given to teams who put up good results against teams rated highly in the NET, which is a good indicator of being able to stand up against tournament-caliber competition.
Strength of schedule is also important, because it is harder for a team to get 20 wins playing in the SEC — which has been the strongest conference in the country this season — than it is in a mid-major league like, say, the Atlantic 10. One key criterion that the committee will often cite when discussing why certain teams missed the field is non-conference strength of schedule, which is the strength of games programs played outside of their respective leagues. Some power conference teams have been hurt by this in recent years (think Wake Forest in 2022 or 2024) by failing to challenge themselves outside of league play, leaving questions about whether they are good enough to take on tournament-worthy competition.
Quality wins are tied into the NET ranking calculation and show how often a given team can beat a tournament-worthy foe. More weight is given to good wins that come on the road or at a neutral site, since the NCAA Tournament will not be played at a given team’s home arena.
The final key piece of data is predictive metrics, which include tools like KenPom’s ratings, BartTovik.com ratings, ESPN’s BPI, Wins Above Bubble and Strength Of Record in addition to the NET rankings. Three of these are based on computer calculations designed to determine which teams would be the best in the field on paper, while results-based metrics (like Wins Above Bubble, which counts wins against teams who are safely in the field) can quantify the work a given team has done on the floor in the regular season.
How the committee ranks teams within the March Madness bracket
Once all 68 teams are selected, the committee ranks them from 1 to 68 and then follows various bracketing principles to create the first-round matchups. Top seeds are usually given geographical preference whenever possible, and the committee also tries to avoid creating matchups between teams from the same conference prior to the Sweet 16.
The committee also will try to ensure that the top four seeds in each region are of comparable strength compared to the overall seed list, in order to avoid having any one region weaker than the rest. In an ideal world, the four regions would have their teams broken down like this:
Region 1: 1st ranked team, 8th, 9th and 16th
Region 2: 2nd, 7th, 10th and 15th
Region 3: 3rd, 6th, 11th and 14th
Region 4: 4th, 5th, 12th and 13th
All four regions here would equal a total of 34, which indicates that the bracket is balanced competitively according to the committee’s seed list.
The use of an S-curve (a seeded list of all 68 teams that would be used to break down teams in a similar manner to a fantasy snake draft, where the No. 4 team would be the worst 1-seed and the No. 5 team would be paired with them as their 2-seed) generally accomplishes that goal, but sometimes other principles may lead to a slight alteration of the typical S-curve. Some examples of this include geography, which could involve a team located closer to a regional site (such as placing St. John’s in the East) getting flipped with another potential team on the same line to ensure the Red Storm don’t have as much of a travel burden.
Another example of this alteration can be found with BYU, which does not play games on Sundays due to its religious affiliation with the Church of Latter Day Saints. The NCAA recognizes BYU’s religious exemption and will only schedule them for tournament sites that play games on Thursdays and Saturdays, which could alter their seed line slightly in order to accommodate the exemption.
Another bracketing principle that the committee considers is trying to avoid regular season rematches for as long as possible, which generally means they want to avoid having teams who played each other in the non-conference face off in the Round of 64 or teams from the same conference meet before the Sweet 16. The recent rounds of expansion that have created four mega-conferences (the Big Ten and Big 12 have 18 teams each, while the ACC has 17 and the SEC is at 16) may make it more difficult to follow this specific principle in the future.