Jenna Robinson’s latest Martin Center column addresses a critical issue for the nation’s historically black colleges and universities.

Earlier this month, the Triangle Business Journal revealed that graduates from North Carolina’s Historically Black College and Universities (HBCUs) are lagging their peers in terms of median salary after graduation. As the state bolsters its efforts to attract more students to its public HBCUs, it’s especially important to discover the cause of such disparities and determine how to close the gap.

The Triangle Business Journal’s findings are a good start. Using data from the Department of Education’s College Scorecard tool, TBJ analyzed the median earnings of students who received federal financial aid ten years after starting their education at each of the ten HBCUs in the state. They discovered that students who attended North Carolina’s public and private HBCUs earn $4,055 less than the national median, and significantly less than most students who attended predominantly white UNC system schools.

Data from NC Tower, a website using government data to track the employment outcomes of public college and university graduates, mostly confirm TBJ’s findings. These data, which come only from students who have graduated by the time of data collection and are employed in North Carolina, show that five years after graduation, most HBCU graduates earn less than those who attended many of the predominantly white institutions (PWI) in the state.

But the disparity between HBCUs and PWIs isn’t cut and dried. To be sure, graduates of UNC-Chapel Hill earn, on average, $20,000 more than graduates of Elizabeth City State University five years after graduation. But these two extreme cases tell only part of the story. Graduates of UNC School of the Arts and UNC Greensboro, both PWIs, earn significantly less than the median for all UNC schools ($33,750). And students at NC A&T, a land-grant HBCU in Greensboro, falls nearly at the median. The income of graduates who stay in North Carolina after leaving school tells an even more complicated story, with graduates of UNC School of the Arts at the bottom and Winston Salem State University at the top. (It is unclear why data from NC Tower and the College Scorecard are so dissimilar for WSSU graduates.)