I interviewed with the DGS at Stony Brook. It was a scripted interview with predictable questions (e.g. what are your research interests, what is your preparation in methods and statistics, Stony Brook is a unique and small department, why do you want to go here? etc.). DGS said "if it's good news from us or a waitlist, you'll hear by the 2nd week of February." DGS said rejections don't come out until later.