The N.C.A.A. tournament opens Tuesday in Dayton, Ohio.
But with a bumper crop of underwhelming at-large entrants, the defining quality of this year’s bracket on Selection Sunday was the weakness of the teams whose bids were in doubt, including those like Iona, North Carolina State and California that made it.
Part of the reason for the glut of marginal teams is the tournament’s recent expansion, which increased the pool of at-large teams from which the committee could choose, to 37 from .
Last season, the field expanded to 68 teams from 65, setting up one opening-round game in each region to complete the bracket. In those games, the last four at-large teams are matched against the last four automatic qualifiers to vie for the four No. 16 seeds.
Among the eight teams playing to get into the field of 64 will be Western Kentucky, Vermont and South Florida.
Iona was among the biggest surprises in the field of 68. The Gaels, who will face Brigham Young on Tuesday in the West Region’s opening round, had no wins against teams in the top 50 of the Ratings Percentage Index, four losses to teams outside the top 100 and a strength of schedule that ranked 144.
The Big East, which placed a record 11 teams into the tournament last year, led all conference with nine teams in the field.

The New York Times