Every school does this differently, but for us we do things on a rolling basis. The most obvious decisions are made first. For instance we might reject a few hundred applications, then next week admit 20 students, and so on. We generally start in Feb, but it goes all the way to mid March. Admissions decisions are made by a committee of professors, so as you can imagine we do have a few other things to take care of
The last decisions to get made are the ones on the edge of acceptance....
So, we made a few more decisions today, and I think within a week we will have everyone accepted, rejected, or wait listed. We are also offering wait listed students the option of coming for an MS degree without support, which I realize isn't exactly what people applied for, but best to give people whatever options we can. My personal feeling is that we won't be taking anyone off the wait list, but we won't know until somewhat after the April 15th deadline for the current admits to give us an answer.
Again, thanks for applying, I know it is stressful.