There are a lot of other threads on this, but I'll go ahead and talk about Yale. Yale has a pretty relaxed atmosphere, and the usual attrition is 1 (max 2) per year, out of a class of about 22.
Until this past year, that is. In a real shock to us, 4 of our 21 will be leaving. I am inclined to think that this is a one-time deal and not a regime shift. Overall, the pressure we feel here is fairly low, I'd say.