Duke vs.UNC

I never said it was the only factor, but I guess “major factor” is an overstatement. Nonetheless it wouldn’t be surprising if the difference between Duke Trinity vs UNC was less than the difference between Duke Trinity+Pratt vs UNC.

Logically, I would assume that many Duke alums live and work in DC and NYC, while the majority of UNC alums probably remain in the Carolinas. If that is the case, it stands to reason that Duke alums earn high salaries since the CoL adjustment alone would make up for most of the difference.

OMG, no! Please don’t get that started

I’d suggest reading what students from both colleges have to say at niche and studentsreview websites - and of course visiting both colleges if you can.
Duke is higher ranked, but that doesn’t mean that UNC is far behind - after all, there’s probably little difference if the academic quality of education between colleges in the top 50 (except that some schools focus on certain majors, etc.)
If you plan to work outside the US, Duke is much more likely to be known than UNC.