Give it until the end of February. If you are still waiting on interview notification in March, then it's probably not going to happen this cycle. The reason I say that is that schools typically go through 3-4 applicant review sessions. They'll meet twice before New Year's and twice afterwards. It's not always this way since some schools have more than 4 meetings or only 3, but that's a ballpark number to go by. February is not the time to worry. March and onward is when it gets dicey because they have either finalized the class already or you will be in the last group of interviews. You must nail the interview and impress with your EC's at that point because stats will not be a strong point if it's that late in the game.