If one carefully looks at 2018-2019 common dataset, 46% of the class received need based financial aid (930 out of 1931). Another 82 received non-need based financial aid (this is probably $2,000 a year aid for national merit finalists, I am not sure what other forms of non-need based aid NU offers). And another 109 received athletic scholarships.
It still does not add up to 61% – it is possible that `financial assistance’ to 61% might include loans offered to some who were full pay after EFC calculations.
I agree that NU is very generous, and these 46% are getting 100% of their need taken care off. Still, the question remains whether there is absolutely no accounting of who has need and who can be full pay when admission decisions are made. Here are the number of students receiving need based financial aid over years
Fall 2018: 930 out of 1931
Fall 2017: 947 out of 1901
Fall 2016: 905 out of 1985
Fall 2015: 982 out of 2017
Given these numbers, I will suspect that some level of profiling goes on in making sure that more than 50% of the class is full pay andNU stays within its financial aid budget. It could be achieved through various means … a large number of ED acceptances probably helps, and there may be other tricks in play (private school attendees, legacy, some idea from profession of parents etc.).