I think that it is hard to tell. Many interviewers try to make you feel really relaxed, so they are nice to you throughout the entire interview and respond very well to everything you say. You walk out feeling like you did very well but you don't get into the school. Then there are some interviewers you see how you do under pressure and they do not respond well to your answers and you walk out feeling like you want to jump off the closest high building you can find. But you actually get accepted.
Just be yourself and stay confident that you did well no matter how you feel after the interview. The only way to know if an interview, IMO, went well is if you get accepted there.
If they say something like " Now how can we convince you to come here?" as the interview's ending, it's pretty good sign. Or if the interviewer is extremely solicitous and helpful about helping you find your way to wherever you're supposed to be next, saying things like "We wouldn't want to lose you..."
But just going by the feeling you have is pretty unreliable. I got some rejects and waitlists from interviews I thought had gone fantastically last year. Remember, coolwaters, the medschool interviewer is not making the decision alone, but only giving input to the adcom that makes the final decision based on the interview plus multiple other factors.
My reply was an attempt to answer Relatively Prime's question: "How do I know if the interview went well?" I agree with you that there are many factors leading to the final admissions decision. The interview is only one component.
My interviewer at NJMS repeatedly said that my file looks exceptional, great, etc.
and she said she could really see me fitting into the school, and she really wants to see me come here.
And she said, "you should have no problem with NJMS, but don't quote me on that... but I will talk to the admissions committee very soon."
So i'm thinking positively about it.
i hope to hear from them soon!