The 68 teams are divided into four regions and organized into a single-elimination ' bracket', which pre-determines – when a team wins a game – which team it will face next. These 'at-large' teams are chosen by an NCAA selection committee, then announced in a nationally televised event dubbed Selection Sunday. The tournament teams include champions from 32 Division I conferences (which receive automatic bids), and 36 teams which are awarded at-large berths. Many handicappers and pundits also offer advice for winning their own bracket. Employers have also noticed a change in the behavior of employees during this time: they have seen an increase in the number of sick days used, extended lunch breaks and even the rescheduling of conference calls to allow for more tournament watching. Mainstream media outlets such as ESPN, CBS Sports and Fox Sports host tournaments online where contestants can enter for free. It has become extremely common in popular culture to predict the outcomes of each game, even among non-sports fans it is estimated that tens of millions of Americans participate in a bracket pool contest every year. Played mostly during March, it has become one of the biggest annual sporting events in the United States.

The tournament was created in 1939 by the National Association of Basketball Coaches, and was the idea of Ohio State coach Harold Olsen. The NCAA Division I Men's Basketball Tournament, branded as NCAA March Madness, and commonly known as simply March Madness, is a single-elimination tournament played each spring in the United States, currently featuring 68 college basketball teams from the Division I level of the National Collegiate Athletic Association (NCAA), to determine the national championship. NCAA Division I Men's Basketball Tournament Current season, competition or edition:Ģ023 NCAA Division I Men's Basketball Tournament For CBS & Turner Sports' coverage of the tournament, see NCAA March Madness (TV program).

Ncaa basketball tournament