"We absolutely aren't trying to discourage people from going to college," said John Schmitt, a senior economist at the Washington-based Center for Economic and Policy Research who coauthored the study. "College degrees do have value. But what we are trying to show here is that this is not about individuals, or individual effort. There is simply overwhelming evidence that discrimination remains a major feature of the labor market."

Schmitt pointed to a series of studies that have in recent years found that when trained sets of black and white testers with identical resumes are sent on interviews, white men with recent criminal histories are far more likely to receive calls back than black men with no criminal record at all.

In fact, the center's study found that even black students who majored in high-demand fields such as engineering fare only slightly better than those who spent their college years earning liberal arts degrees. Between 2010 and 2012, 10 percent of black college graduates with engineering degrees and 11 percent of those with math and computer-related degrees were unemployed, compared with 6 percent of all engineering graduates and 7 percent of all those who focused their studies on math and computers.

College-educated blacks are also more likely than all others with degrees to confront underemployment, which the study defined as working in jobs that don't require a four-year degree. The proportion of young African-American college graduates who are underemployed has spiked since 2007 by fully 10 percentage points to a striking 56 percent. During that same period, underemployment among all recent college graduates has edged up only slightly to around 45 percent.

The study also found that among older college graduates, the gap in the unemployment rate narrows but doesn't disappear. Bureau of Labor Statistics data indicates that in 2013, 3.5 percent of all white college graduates were unemployed while nearly 6 percent of all black college graduates sought work but could not find it.

Many studies have found that workers unable to find steady employment during their first years in the labor market often pay long-term costs. During the first five years after school, people try on, discard and pick up better-fitting careers, develop key skills, typically make major income gains, and begin to plug into the professional networks that provide training, contacts, and new job opportunities in the future. When unemployment disrupts that process it can permanently alter the trajectory of a worker's lifetime earnings, economists have concluded.

The situation for other minorities falls somewhere in between that of blacks and whites, according to federal data. In 2013, the share of all college-educated Asian-Americans who were unemployed roughly equaled the proportion of whites: 3.6 percent. All Hispanic college graduates faced a 5 percent unemployment rate, more than whites but less than African-Americans.