I applied last year and I would say I was middle of the pack. I applied to 8 schools and got accepted into 3, I was waitlisted at all of the others. I heard from one early January but didn't hear from the others until beginning of February. I would say that generally if you haven't been contacted by March for interviews then you have been waitlisted or rejected. IO does go slower than other psychology fields for grad school applications at some schools.