The tournament’s selection committee plays a role in upsets, too. East Tennessee State came into the 1989 tournament with impressive wins over Mississippi State and Wake Forest, two major-conference teams. According to Sports Reference’s Simple Rating System, which measures a team’s strength of schedule and margin of victory, the Buccaneers were the eighth-worst team in the field, meaning they were closer to a 14 seed than their 16.

East Tennessee State ended up losing to Oklahoma by one after leading by 17. “It’ll take a mistake on the committee’s part,” said Les Robinson, the Buccaneers’ coach at the time. “They hadn’t done their homework on us.”

No. 16 seeds also have found success with another equalizing basketball strategy: zone defense. In zones, defenders are responsible for areas of the court instead of specific players, which prevents offenses from driving and causes them to shoot more three-pointers. This can make great teams mediocre: This year’s No. 1 seeds shoot 35.9% on three-point attempts, only slightly better than the national average, and shot 27.2% in their losses.