How should I compare Duke and UC San Diego’s undergraduate selectivity without relying only on acceptance rates?

Duke is more selective overall for undergraduate admission, even when you set aside a single year’s acceptance rate.

UC San Diego is also highly selective, but as a large public research university it enrolls far more undergraduates and has a distinct responsibility to serve California residents.

Yield is a useful long-term indicator. A school with a very high yield has many admitted students who choose to enroll, meaning it can admit fewer applicants than a similarly desired institution to fill its class. UC San Diego’s yield is strong as well, but it operates in a public-university system where applicants commonly apply to several campuses.

Duke’s process weighs academics, activities, recommendations, essays, and institutional priorities in a small, private-university setting; its Early Decision round also attracts applicants ready to commit. UC San Diego uses the University of California’s comprehensive review process and is test-blind, while demand can vary significantly by major.

Duke should be treated as a high-reach school for nearly every applicant. UC San Diego is also a reach for many strong students, but its competitiveness is more affected by California residency, intended major, and the UC-wide application context.