First, no interviews for EdD, only EdLD. From what I understand the acceptance rate depends on the concentration, whereby some concentrations have a higher number of applicants than others. While HGSE says they try to take an even number from each concentration, it also in part depends on the number of students each adviser says they can manage. I've read acceptance rates from 6-7% at HGSE on a different websites, too. From what I have been told, 50% of those are people are just applying to Harvard because of the name and/or not really into education. The Admissions Office believes they identify those prospects pretty quickly and toss them. While I do think that there is some sense of pride in selective admissions numbers, I also think the raw number has questionable value, which is really why they don't publish it.