@JBStillFlying
“UChicago has had loads of early applicants relative to other schools for a long time, not just after introducing ED last year.”
You misunderstood my point. UChicago had loads of early applicants for a long time because it had, and still have, EA. What changed is it now also has ED. ED helps UChicago improve its YIELD significantly while keeping admit rate low with its EA program.