Something I learned from this thread, which is a change from the last time I had looked, some years ago, is that the numbers for Duke’s ED and Princeton’s SCEA have practically converged, with Princeton admitting just under 20% of its early applicants and Duke admitting just over 25% of its early pool. It’s really interesting that they are so close; I would have thought Duke’s rate would be more like twice Princeton’s – because Princeton is more popular (but Duke gets meaningfully more applications overall), because EA schools tend to get more applications than binding ED schools (but the SCEA schools have not had huge growth in early applications, and Duke has), and because Duke enrolls a larger class than Princeton (but it only takes slightly more ED).
I wonder whether part of the difference isn’t explained by Duke not using ED to admit its recruited athletes. If one hypothesizes that Duke is bringing in a couple hundred athletes via an NLI process and not counting them in ED, and adjusts Princeton’s numbers accordingly (since Princeton almost certainly is running most of its recruited athletes through ED), the gap between their early admissions rates would be 10 percentage points, not 5.