Applied on 10/6 RD.
Their website says don't expect much news for RD candidates prior to 12/1 but it is worded in a way that will put interviews and decisions to January. Looking at the # of posts from RD candidates who submitted as early as September, I wonder if the backlog is enough to not hear back till December at all.
Personally, since I am re-applicant this year, even though not to Columbia, I don't mind the wait. Last year I spent so much time speculating and trying to figure out what will happen, that nothing went the way it was suppose to. I got interview invites crazy late at places, and got invites crazy early at some.
I know waiting is hard, but there is no method to this madness.
My two cents