<p>Google the nytimes choice blog from yesterday; it has some ED figures from various universities.</p>
<p>I don’t know why a university wouldn’t try to lock in as many ED’s as possible. Lock in full-pays, protect your yield, make it so that there is less guessing work in May about who will come and who will won’t, less chance of either having unfilled beds or having to rent a room at the local hotel to deal with the overflow. Frankly I’m surprised that some reasonably-top university hasn’t decided to do the prisoners-dilemma thing and move towards all decisions by December 31 (or so).</p>