Here's some more info for you and everyone waiting on Vandy IGP: I work at Vanderbilt and have gotten some info from some IGP graduate students. The committee meets every Tuesday and evaluates small batches of applications each week, so I'd assume interview invites are sent out on Wednesdays and Thursdays. Do not worry if you haven't heard anything!!!!!! I would guess they go through the applications in the order they were received but I'm not really sure about that. But the invites will definitely keep getting sent out gradually, I'd guess even into February. Hope this helps ease some stress:)