Why so many get waitlisted?

Thread		Replies	Views
Is it true that WUSTL waitlists a lot of people? Washington University in St. Louis	13	48	April 17, 2021
% of Applicants Waitlisted for WUSTL Washington University in St. Louis	5	47	April 17, 2021
How Many Admits from Waitlist Washington University in St. Louis	4	43	April 16, 2021
Does Wash U's wait list = rejection Applying to College	13	60	April 16, 2021
Waitlist Washington University in St. Louis	12	52	April 17, 2021