Advice on wait list situation?

[2017]

So I was wait listed at my top program in the beginning of March. I was told that my chances of being offered a spot off the waitlist are "very good", and that while I couldn't be told my exact ranking on the list, it is "very, very, very high". 

I've been in contact with many of the people who were accepted to this program, and one of them just recently turned down an offer and informed the program a few days ago. Knowing that I'm high on the waitlist and that April 15 is quickly approaching, I contacted my POI and asked if there might be any update with regards to my application status. He just responded, saying that they "are not yet at a point where [they] can move to the waitlist" and that the waitlist is  "a frustratingly complicated process, the details of which I’ll spare you". He then went on to say that it's still very possible that they will move to the waitlist and that they are "hoping and trying to get to it". 

His evaluation of the waitlist process as being a "frustratingly complicated process" and that the department is "trying to get to [the waitlist]" is making me wonder if there is some kind of university-wide blockade in the place that the department has to maneuver around before the graduate school allows them accept and fund waitlisted applicants. Does anybody have any idea if this is common or even a thing? I suppose it's also possible that more than one person needs to decline an offer before the department can move to the waitlist, although my sense is that this is less likely to be the case, as the department accepts 7 students and hopes to enroll 7. So, for every declined spot, there should be a waitlist acceptance. I'm sure waitlist processes differ vastly from school to school, but does anyone have any potential insight on this?

[fuzzylogician]

Well, there are several options.

One is that they made more offers than they want students in their cohort. That's actually extremely common, even among the most competitive programs. You'll make n offers and expect a yield of m<n as a result. If you don't get enough students after this first round, you might go to the waitlist, but you will want to wait until you have a better idea of the size of the cohort, it's not enough for one student to decline. 

Another is that the waitlist is not strictly ranked, so there will be some politics that goes into who is offered a spot off the waitlist. If so, this will depend on internal complex power struggles. It will possibly matter not only that someone declined, but also what their field was, to try to accept someone else with similar interests to keep a balance.

Yet another is that there needs to be an official department meeting or some other official and complex bureaucratic shenanigan that needs to happen before the department can move to the waitlist, usually involving several people, some of whom busy and/or slow. (This is actually quite likely.)

It might be that some student was offered more money to try to attract them to the program, but that holds up more money so even though someone else declined, they're still waiting to figure out the money situation. 

I don't think it's common for this to depend on some university-level decision making at this point, although it is of course possible that changes in budget will affect how many students can be funded this year -- but that should have been decided long ago! It could still be that something changed in the funding situation, but I don't think that's likely the case.