...The economists and education researchers tracked thousands of people over the last two decades in Florida, Georgia and elsewhere who had fallen on either side of hard admissions cutoffs. Less selective colleges often set such benchmarks: Students who score 840 on the SAT, for example, or maintain a C+ average in high school are admitted. Those who don’t clear the bar are generally rejected, and many don’t attend any four-year college.
Such stark cutoffs provide researchers with a kind of natural experiment. Students who score an 830 on the SAT are nearly identical to those who score an 840. Yet if one group goes to college and the other doesn’t, researchers can make meaningful estimates of the true effects of college.
And the two studies have come to remarkably similar conclusions: Enrolling in a four-year college brings large benefits to marginal students. Roughly half of the students in Georgia who had cleared the bar went on to earn a bachelor’s degree within six years, compared with only 17 percent of those who missed the cutoff, according to one of the studies, by Joshua S. Goodman of Harvard and Michael Hurwitz and Jonathan Smith of the College Board. The benefits were concentrated among lower-income students, both studies found, and among men, one of them found.