An at-large bid is a bid or berth in a sporting tournament granted by invitation, not right. This term is most commonly used in the United States to refer to berths that the NCAA grants in its annual Division I men's and women's basketball tournaments, although at-large berths are granted in almost all championship tournaments the NCAA conducts.
The NIT, held for the best teams that didn't make the NCAA Tournament, was at one time an entirely at-large event; new regulations, however, offer automatic bids to teams regular season conference champions which failed to win their post-season conference tournament.
This article focuses mainly on the most common use of the term, in reference to the basketball tournaments. However, a similar procedure applies in most other NCAA-sponsored tournaments, and in other tournaments that use an NCAA-style system.
Each year, the NCAA grants automatic berths in both the men's and women's Division I basketball tournaments to the winners of 31 conferences. In all cases, the conference's automatic berth is granted to the team that wins its conference postseason tournament, with the sole exception of the Ivy League, which has never conducted a postseason tournament. The Ivy League berth is granted instead to the regular-season champion.
The NCAA has established Selection Committees for both the men's and women's tournaments. Teams that did not win their conference tournament may be eligible to earn an at-large berth. At-large berths are determined by record, ranking, strength of schedule, and many other factors. A key factor in determining at-large berths is the Ratings Percentage Index, popularly referred to as the RPI. One absolute rule is that a team with a losing record after the conference tournament (or regular season in the case of the Ivy League) is barred from consideration for an at-large berth.
The fields of 68 teams that participate in the men's tournament, and 64 for the women's tournament, are filled as follows:
After all automatic berths are filled, the teams that did not win their conference tournaments are studied to see if they can make the tournament anyway. Once conference tournaments are complete, the Selection Committee need not consider conference affiliations in determining at-large berths, making it free to select as many teams from one conference as it deems correct. Most mid-major conferences or smaller conferences will receive no at-large berths, and only the winner of the conference tournament will advance to the NCAA Tournament, making for some heartbreaking moments in the tournaments of smaller conferences.
The conference tournaments of major conferences are generally less important, as most losers will make the "Big Dance" via an at-large bid, but often lesser big conference teams will sneak in using the conference tournament, stealing a bid from a deserving mid-major team in the long run.
At-large berths are not necessarily lesser teams than automatic berths. They simply did not play well enough at the time of their conference tournaments. Often, at-large berths will get higher seeds than the teams that beat them in the conference tourney, because the Selection Committee judges base their judgment on the entire season.
Division I independents do not play a conference tournament and therefore do not have an automatic berth, and can only receive an at-large bid to the tournament, which rarely happens in today's game. Sometimes, a team that is otherwise deserving of a bid may be ineligible for the tournament due to an NCAA post-season ban, applied only as a punishment for egregious violations of NCAA rules in that school's program in that sport.
With a 68-team field (64 for women), and 31 automatic berths, the Selection Committee must pick the 37 (men's) or 33 (women's) most deserving teams that are left, which ends up being a long difficult process, which culminates in one of the most intense days in U.S. sports, Selection Sunday. Selection Sunday is a televised event where the brackets are revealed. There are almost always interesting arguments about who should be in and who should be out because there are often more than 34 teams that could be considered deserving of a bid. Many final teams that make it, and final teams that are cut are often thought of as interchangeable. This ends up resulting, sometimes, in major surprises of who makes the tournament as at-large teams. At-large teams often will win the tournament.
The conferences that are known for many at-large bids are generally the six BCS conferences: the ACC, Big Ten, Big 12, Big East, Pac-12, and SEC. ("BCS" refers to Bowl Championship Series, the current system used to determine the championship of Division I-A football.) Those conferences, which contain most of the marquee schools in college basketball, typically receive many at-large berths. They usually get at least four at-large bids, despite the lack of an official rule requiring this allocation. While these schools often win their conference tournament, they equally often do not, and therefore usually make the NCAA Tournament via at-large berths.
Other conferences that receive multiple at-large bids on a regular basis are the Atlantic 10, Missouri Valley, Mountain West, WAC and Conference USA (although since the loss of many of that conference's top teams to the Big East and A-10, this may change). In recent years, the Horizon League, Mid-American Conference and West Coast Conference have also received more than just the automatic berth several times.
Certain conferences have never, and probably will not in the near future, get an at-large bid, simply because no team in the conference can ever be one of the best 68 teams in the country, and even if one does, two at the same time would be virtually unheard of. Therefore, it is also often argued that these very small conferences do not even deserve their one automatic bid and it should be given to a more deserving large conference team. Most argue that this would take away from the point of the 68-team large tournament style, that always gives the underdog the chance for an upset. These conferences include the Big Sky Conference, the Metro Atlantic Athletic Conference, and the Southwestern Athletic Conference. One of these conferences recently made an argument for their best team to make the tournament, even though it lost in the conference tourney. Oral Roberts of the Mid-Continent Conference blew through their conference in the regular season but lost in the conference tournament, ending with a conference record of 17-1. They did not make the tournament, and Oakland University won the bid. Utah State and Holy Cross also had arguments like this recently. A new way to solve the problem is to attempt to switch to a more prominent conference, which Utah State did in 2005 (Big West to the Western Athletic), or Central Florida did in 2005 (Atlantic Sun Conference to the C-USA).
Arguments such as this continue and there will always be much controversy surrounding at-large bids.