I had a PD tell me that I do not necessarily have a legitimate shot at some places, even if they have offered me an interview. I respect the guy, but I'm still surprised to hear it.
Do programs really interview applicants that may not have a legitimate shot at their program?
I can most certainly say that, unless you are a terrible human being, try to sleep with the PD's wife, or get arrested for prostitution DURING your interview, you will be on the rank list. The point is, only EXTREME circumstances get you "not ranked."
That being said, most programs interview for 5-10 times the number of slots they have. 30 spots, 300 interviews. 5 spots, 25-50 interviews. 5 being the usual, 10 being probably too many. What that means is that if you are in that bottom 5x, you are not likely to match in that program. People who are in the top 1x are guarenteed acceptance, people in the 3x range will more than likely get in, and people in the 5x generally do not.
So... "you don't have a shot necessarily" means that you interviewed, but ended up in the 5x slot on their rank list. Possible? Certainly. Worrisome? Nah. The point is that if you manage to get a UCSF interview, but then all your others are community programs or second-tier categoricals, you're probably going to be UCSF's 5x. If you get Duke, Yale, Harvard, Hopkins, Wash U, and UCSF... you're 1x on those community programs and probably 3x on the big dogs. Translation: the more quality programs you apply to, the more likely you will have a spot higher up on multiple rank lists.
Make sense?