In 2005, the National Basketball Association mandated that future draft prospects must be at least 19 years old and a year removed from high school before they can become eligible for the NBA draft. Thus, the prep-to-pro era of professional basketball reached its end.
Prior to the rule change and after the NBA/ABA merger, however, 39 players were drafted to the NBA straight out of high school. Of those 39, 36 went on to play at least one game in the pros. PointAfter, a sports data visualization site that's part of Graphiq, set out to rank every prep-to-pro player from worst to best.