The real ED-vs-RD admit rate gap exists because binding ED commitments lock in a large share of the incoming class before Regular Decision opens at all -- and Northwestern's Class of 2030 is a real, sourced example of just how large that share can get.
The real example: more than half of Northwestern's class, before RD even opened
Northwestern's own student newspaper, The Daily Northwestern, reported directly that more than half of the Class of 2030 was admitted through Early Decision -- consistent with recent cycles, where ED admits have made up roughly 55% of the incoming class. That's a concrete confirmation of what the ED-vs-RD gap data implies more abstractly: at a school locking in that much of its class early, the Regular Decision round is competing for what's left of an already-shrunk number of seats, not a fresh, undiminished pool.
The honest limit on this number
Northwestern has not officially published an exact Early Decision admit rate for the Class of 2030 -- the "more than half the class" figure is the paper's own confirmed reporting on class composition, not the same thing as a precise admit-rate percentage. Third-party estimates put the rate near 18-19%, based on application volume and historical patterns, but treat that specific number as an estimate, not a school-confirmed figure -- the same distinction the main ED-vs-RD breakdown already draws for Dartmouth and Columbia's undisclosed numbers.
A related, growing pattern: schools that stop publishing round-level data at all
Northwestern still confirms the broad shape of its ED class share, even without an exact rate. Other schools have stopped disclosing round-level admissions data entirely -- Dartmouth and Columbia, already covered in the main breakdown, and the University of Pennsylvania, which stated directly for its Class of 2030 results that it "did not disclose a regular decision acceptance rate, continuing its policy of withholding detailed admissions results since 2022." That's a real, growing pattern worth tracking on its own: as more schools stop publishing exact round-by-round numbers, real, current, school-confirmed data like Brown's, Vanderbilt's, and Duke's becomes more valuable, and any specific figure for Dartmouth, Columbia, or Penn should be treated as a third-party estimate rather than a confirmed number, regardless of how confidently it's stated.
What this means for you
- The admit-rate gap and the class-fill share are two sides of the same mechanism -- a school locking in 55% of its class through ED, like Northwestern, has structurally fewer seats left for the RD pool, which is a real part of why RD admit rates run so much lower.
- Don't treat "more than half the class" and "an exact 18.75% admit rate" as equally solid -- one is Northwestern's own confirmed reporting, the other is a third-party estimate built from incomplete public data.
- Add Penn to the list of schools no longer publishing round-level rates, alongside Dartmouth and Columbia -- any specific ED or RD percentage you see for these three schools is an estimate, not a number any of them has confirmed.
- This reinforces why the main data set only uses schools with real, current, direct disclosure -- see the full school-by-school breakdown for why Brown, Vanderbilt, Duke, and Emory's numbers specifically are trustworthy in a way estimates for other schools aren't.