>Could be a lot of things happening. It could be something like, fewer Black people are accepted to university in the first place, which means that the work ethic and skill level or aspirations of many of those few who are accepted are equivalent to the top 25% (arbitrary number) of white candidates, for whom college is a given, so they are more likely to continue as a group.

If that was a leading factor, we would see a similar trend for hispanics, but we observe the opposite.

>It could be cultural. Both the feeling that you have to be a "good" representative of your race, and the fact that most of your peers of the same race feel the same way will push you to achieve more/avoid "failure". It could also be the reasons that they are choosing university in the first place. Social work, Healthcare, education, and so on are fields where getting a masters is often necessary. I don't know if there is specific pressure from parents of high performing Black students to go towards specific fields or not the way there is for Asian students to go into engineering or medicine.

That's an interesting hypothesis. It would be interesting to see a comparison of the fields of study for different racial ethnicity to verify this hypothesis. If blacks do indeed disproportionately choose fields of study that require a master's degree it could support your hypothesis.

>It could also be that recently graduated Black students find themselves unable to find the same caliber of job opportunities as their white peers so have to continue education to find good jobs in their field.

Unlikely considering the data for other ethnicities and for African born black immigrants.