NCAA Tournament Bids by Conference: A Historical Overview

The NCAA Division I Men's Basketball Tournament, popularly known as March Madness or The Big Dance, is a single-elimination tournament held annually in the United States. It determines the men's college basketball national champion at the Division I level of the National Collegiate Athletic Association (NCAA). First played in 1939, the tournament has evolved significantly over the decades, expanding in size and capturing a prominent place in American sports culture. This article delves into the historical data of NCAA Tournament bids by conference, examining trends, shifts in power, and the factors influencing conference representation in March Madness.

Evolution of the NCAA Tournament

Early Years and Expansion

The inaugural NCAA Tournament in 1939 featured just eight teams, selected from geographical districts. From 1939 to 1950, the NCAA tournament consisted of eight teams, with each selected from a geographical district. Multiple conferences were considered part of each district, such as the Missouri Valley and the Big Seven conferences in one district and the Southern and Southeastern conferences in another, which often led to top-ranked teams being left out of the tournament. Over time, this format led to controversies, as top-ranked teams were often excluded. In 1951, the NCAA doubled the field to 16 teams, adding two additional districts and six spots for at-large teams. Conferences could still only have one team in the tournament, but multiple conferences from the same geographic district could now be included through at-large bids. The number of participating teams fluctuated between 22 and 25 from 1953 to 1974, with some teams receiving byes to the Sweet Sixteen.

The Rise of At-Large Bids and Seeding

A significant change occurred in 1975 when the NCAA allowed multiple teams per conference. To accommodate at-large bids, the tournament expanded in 1975 to include 32 teams, allowing a second team to represent a conference in addition to the conference champion, and eliminated byes. This decision, coupled with a 1971 rule preventing teams declining an NCAA invitation from participating in other postseason tournaments, solidified the NCAA Tournament's prominence. This was in response to eighth-ranked Marquette declining its invitation in 1970 and instead participating in and winning the NIT after coach Al McGuire complained about their regional placement. The tournament further expanded to 40 teams in 1979, adding seeding to enhance competitiveness and ensure better pathways for top teams to the Final Four.

Modern Era: 64/68-Team Format and Beyond

In 1985, the tournament expanded to 64 teams, eliminating all byes and play-ins. For the first time, all teams had to win six games to win the tournament. This expansion led to increased media coverage and popularity in American culture. The field expanded again in 2001 to 65 teams, introducing the "play-in game," and ultimately to 68 teams in 2011 with the creation of the First Four. The 68-team format was adopted in 2011; it had remained largely unchanged since 1985 when it expanded to 64 teams. Before then, the tournament size varied from as little as 8 to as many as 53. The field was restricted to conference champions until at-large bids were extended in 1975 and teams were not fully seeded until 1979. The First Four was created by the addition of three play-in games. Two of the First Four games pit 16 seeds against each other. The two other games, however, pit the last at-large bids against each other. The seeding for the at-large teams will be determined by the selection committee and fluctuates based on the true seed ranking of the teams.

The Selection Process

The tournament consists of 68 teams competing in seven rounds of a single-elimination bracket. Thirty-two teams automatically qualify for the tournament by winning their conference tournament, played during the two weeks before the tournament, and thirty-six teams qualify by receiving an at-large bid based on their performance during the season. The Selection Committee determines the at-large bids, ranks all the teams 1 to 68, and places the teams in the bracket, all of which is revealed publicly on the Sunday before the tournament, dubbed Selection Sunday by the media and fans. The tournament is divided into four regions, with each region having sixteen to eighteen teams. The Selection Committee, which includes conference commissioners and university athletic directors appointed by the NCAA, determines the bracket during the week before the tournament. To make the bracket, the Committee ranks the whole field from 1 to 68; these are referred to as the true seed. The committee then divides the teams amongst the four regions, giving each a seed between No. 1 and No. 16.

Conference Representation in March Madness

Power Conferences vs. Non-Power Conferences

Conferences are not created equal, and March Madness perfectly highlights the stark divide between different conferences. From 2005 to 2025, a total of 32 conferences have been represented in the NCAA Tournament (31 in 2025), each fighting for a spot in the 68-team field. Every conference tournament champion earns an automatic bid, while the remaining 37 at-large spots are up for grabs. Not all conferences see the same level of representation. Of the 32 conferences which have participated in March Madness between 2005-2025, 13 conferences have only ever received one bid per year. These include the Atlantic Sun, America East, Big Sky, Big South, Ivy League, MAC, MEAC, Northeast, Patriot, SWAC, Southern, Southland, and Summit Conferences. At the other end of the spectrum, 6 conferences have never received fewer than two bids in a single year. These are the current and former Power (high major) conferences which include the Atlantic Cost (ACC), Big 12, Big East, Big Ten, Southeastern (SEC), and Pac-12 Conferences. The above graph shows the divergence in distributions of the number of March Madness bids per year by conference. The Power conferences have significantly more representation per conference than non-Power conferences. The only other conferences which typically receive more than one bid include the American Athletic (AAC), Atlantic 10, Mountain West, and West Coast Conferences. These leagues have consistently produced at-large selections.

Factors Influencing At-Large Bids

Several factors influence the number of at-large bids a conference receives:

NET Rankings: The NCAA Evaluation Tool (NET) rankings, introduced in 2018, replaced the RPI with the intention of developing a ranking system that could not be unfairly manipulated by any team. However, evidence suggests that the NET rankings are unintentionally biased in favor of the Power conferences because of the Selection Committee’s emphasis on Quad I wins. Teams in Power conferences naturally have more Quad I opportunities due to stronger schedules. As a result, non-Power conference teams with strong records often rank lower than Power conference teams with mediocre records.
NIL Collectives: The rise of Name, Image, and Likeness (NIL) collectives has enabled Power conference programs to attract top-tier recruits and transfers, giving them a significant talent advantage over the majority of their non-Power conference counterparts. Power conference programs have built multimillion-dollar NIL war chests to attract top-tier recruits and transfers, giving them a significant talent advantage over the majority of their non-Power conference counterparts.
Conference Realignment: The Power conferences are consolidating and absorbing historically strong non-Power conference basketball schools. For example, in 2013, Xavier, Butler, and Creighton all joined the Big East from the Atlantic 10 and the Missouri Valley Conferences. Ten years later, Houston, Cincinnati, UCF, and BYU all joined the Big 12 from the AAC and WCC. This consolidation has strengthened the Power conferences, ensuring that these successful programs now receive Power conference bids rather than non-Power conference bids.

Historical Trends in Conference Bids

Big Ten: Over this 20-tournament span (excluding 2020, when the event was canceled due to COVID-19), the Big Ten leads the way with a median 7 March Madness bids per year. The Big Ten arose as the next juggernaut conference and led all conferences in March Madness bids in 2019-2022. In general, the Big Ten has been on an upward trajectory for the past decade. Between 2005-2014, the Big Ten never sent more than 7 teams to March Madness, but since 2015, there have only been two years in which the conference sent fewer than 7 teams. Every year since 2019, the conference has been one of the top two conferences in representation in the tournament.

Big East: The Big East and Big 12 follow closely behind with a median 6 March Madness bids per year. Before 2013, the Big East was the powerhouse conference, consistently sending the most teams to March Madness. At its peak in 2011, the Big East sent a record 11 teams to the NCAA Tournament-more than any conference in history at the time. However, in 2013, the Big East fundamentally restructured as Syracuse, Pittsburgh, and Louisville departed for the ACC (joined by Notre Dame in non-football sports), Rutgers departed for the Big Ten, and West Virginia departed for the Big 12. While the basketball-focused Big East remains competitive, its representation has declined significantly. Since 2014, the Big East has averaged only 5 bids per year compared to 7.9 bids per year between 2005-2013. This decline has had significant financial implications. Conferences will take home around $2 million each per representative in the Big Dance this season. That represents almost $6 million in lost revenue per year for the Big East.

ACC: The ACC with 5.5. Following the Big East’s decline, the ACC emerged as the dominant conference, reaching its peak in 2017 and 2018 with 9 teams earning bids each year. However, the ACC’s influence has faded significantly in recent years. The post-COVID-19 era has been particularly unkind, with fewer teams selected each year. The 2025 tournament saw just 4 ACC teams make the field-its lowest number since 2013 and the smallest share of Power conference bids since 2011. In fact, many bracketologists postulated that the ACC might only receive 3 bids this year, but North Carolina narrowly avoided exclusion as a controversial choice for the Last Four In.

Read also: Crafting Your NCAA Profile

SEC: The SEC with 5. No conference has risen faster than the SEC, culminating in a record-breaking 14 bids in 2025-the most ever awarded to a single conference. On Selection Sunday 2025, the SEC made history, securing an NCAA record 14 tournament selections to the March Madness field. No conference has ever achieved such a feat. The previous record belonged to the Big East in 2011, when 11 teams from the conference earned a spot in the tournament. The SEC’s growth was not immediate but has been trending upward since 2018, when the league first claimed more than 20% of Power conference bids with 8 teams in March Madness. Prior to 2018, the SEC averaged just 4.4 bids per year, but since then, the number has nearly doubled to 8.1 per year. Not only has the SEC achieved a record number of bids, but it received two of the No. 1 seeds, including the No. 1 overall seed Auburn, and two of the No. 2 seeds in the tournament. With massive financial investments, elite coaching hires, and a thriving NIL landscape, the SEC is positioning itself as the premier basketball conference of the future.

Pac-12: The Pac-12 with 4. Meanwhile, the Pac-12 struggled to keep pace. From 2017 to 2024, the league averaged just 3.7 bids per year, the lowest share of any Power conference. With realignment gutting the Pac-12 in 2024, UCLA, USC, Oregon, and Washington left to the Big Ten, and Arizona, Arizona State, Colorado, and Utah left to the Big 12. It remains to be seen what the future holds for the historic conference. This season, both Oregon State and Washington State played in the West Coast Conference.

Big 12: Unlike other conferences that have risen or fallen, the Big 12 has been a model of consistency. Since 2014, the conference has received between 6 and 8 bids every year, never leading all conferences but always among the top contenders.

Conference Performance in the 2025 NCAA Tournament

SEC: The SEC getting 14 out of its 16 teams into the field shattered the Big East’s previous record of 11 bids. After going a dreadful opening round (3-5) in 2024, the SEC improved slightly with an 8-6 record in 2025. Although the top seeds mostly advanced outside of Missouri’s loss to Drake, the bottom six seeds in the SEC went 1-5 in the first round. Final Four runs by the SEC’s six top-four seeds will dictate the postseason success of the league.
Big Ten: Massive start for the Big Ten with all eight teams winning in the first round. Eight wins already surpasses six wins from two years ago and positions the league to have more than 10 wins from last season. It also matches the first round win total with the SEC - with the Big Ten having six fewer bids. The addition of Oregon and UCLA earned the Big Ten two additional wins with opportunities to advance to the second weekend. Big Ten teams had the better seed in all eight matchups in the first round.
Big 12: The new-look Big 12 saw Kansas lose and the rest of the conference advance to the Round of 32. With a very solid 6-1 mark, the Big 12 is off to a great start in the 2025 NCAA Tournament. With four stronger seeds in second round matchups, the Big 12 has a chance to make some noise after only Houston and Iowa State made the Sweet Sixteen last season.
Big East: A 4-2 first round is solid. St. John’s is the only stronger seed in the second round, however as the Big East lacks a lot of true title threats. UConn’s NCAA Tournament win streak reached 13 with its win over Oklahoma as the defending champions are still a dangerous No. 8 seed.
ACC: After going a ridiculous 8-1 during the opening weekend of the 2024 tournament, the ACC saw Clemson and Louisville lose to weaker seeds while North Carolina ended its disappointing season with a first-round loss to Ole Miss.
Mountain West: The Mountain West rebounded on Friday after a sluggish start. Double-digit seeds New Mexico and Colorado State winning was a nice bounce-back from San Diego State and Utah State both suffering blowout losses.
WCC: The WCC made a positive impact in the first round with a 2-0 record - with both wins coming against the juggernaut SEC. For the 16th consecutive NCAA Tournament, Gonzaga advanced to the Round of 32 following its blowout win over Georgia. Saint’s Mary’s reached the Round of 32 for the third time in four years with its comeback win over Vanderbilt.

Individual Teams and Tournament Success

Throughout the history of the NCAA Tournament, certain teams have consistently demonstrated excellence. UCLA holds the record for the most championships with 11, followed by Kentucky with eight, and North Carolina and UConn with six each. These programs have not only secured multiple titles but have also consistently earned bids, reflecting their sustained success.

Impact of COVID-19

The COVID-19 pandemic significantly impacted the NCAA Tournament. The 2020 tournament was canceled outright. Initially, the NCAA discussed holding a shortened version with only 16 teams in the Final Four host city of Atlanta. In 2021, the tournament was held entirely in the state of Indiana to reduce travel. This was to date the only time the tournament was conducted in one state. As a COVID-19 precaution, all participating teams were required to stay in NCAA-provided accommodations until they lost. The schedule was adjusted to provided extended time for COVID-19 evaluation before the tournament began, with the First Four occurring entirely on Thursday, the First and Second Rounds pushed one day back to a Friday-Monday window, and the Sweet Sixteen and Elite Eight pushed to a Friday-Monday window as well. Teams ranked 69-72 by the Selection Committee were put on "standby" to replace any team that withdrew from the tournament due to COVID-19 protocols during the 48 hours after the brackets were announced. Only one game was declared a no contest due to COVID-19, with Oregon advancing to the second round because VCU could not participate due to COVID-19 protocols. VCU was not replaced by one of the first four teams out because the COVID-19 infections started more than two days after the brackets were announced.

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