I interview people for a competitive peds fellowship.
Because there are so many applicants for each spot, much more than we can interview, there are some fairly arbitrary non fixed cut offs right off the bat. This is all done by the fellowship directors and their admin assistant. The match changed things a lot over the last few years. We have to interview a lot more people now to have a reasonable list. Previously it was just interview the best first. If we liked them, give them an offer immediately. We'd fill up fast with the applicants we liked and be done.
Anyway-
Marginal in service exam scores and the possibly of not passing the boards? Pass. Failing the boards and not getting a job is your problem, we don't want it to be our problem.
Incomplete application/ docs? Pass. If you want a fellowship, you'd take care of this. Don't expect a call.
Applying very late? Pass. It raises concerns about your motivations, and have reviewed others already. If you're a super star, you can overcome this with a good letter IF we have availability.
Visa issues, etc. Pass. Another potential headache we don't need.
Other big red flags, drug or alcohol problems, training extensions, etc. not related to something like an accident, pregnancy, etc. Pass. Someone else can take a chance on you. I came from a real honor code so I will hold you to a higher standard for those kinds of offenses if I see them in your record. If you don't like it, tough.
Obvious questionable mastery of the English language? Pass.
What matters the most? Pedigree. We get most of our fellows from the same handful of known strong programs in our general area year after year. Why? Because we know that they turn out high quality well prepared fellows. There are also a couple dead man walking applicants that have no chance due to problems with previous applicants/fellows from their residency. "They don't even know that they're dead." Blame your attendings for graduating marginal residents and then selling them as superstars.
How they go about splitting hairs on the bulk of the applicants is a mystery. Scores matter. I would expect LORs make a very very big impression. For the most part, all the LORs I've read are outstanding, so the average, read between the lines, "this guy is ok" letters must be coming in, but not making it to my mailbox. That's great that you're polite, trainable and aren't killing patients, but what else have you got? These LOR writers know you well, or should, if they have nothing glowing to say about you that says a great deal. We want great fellows with great potential, that's not you.
Being a chief or having a few years of experience and being board certified will also help. You're bringing more leadership and/or experience and/or maturity to the table. That's appreciated. A minority worry about how you will be able to handle giving up control and being a trainee again. I don't, as I did myself, but a few may raise this concern and potentially hold it against current attendings if they don't like the answer you give to these questions.
Research. Everyone loves some good research. If you want to find success in academia, get started early. All the big programs have some kind of academic requirement, and we want to know you can succeed. We are also a fairly academic bunch, with lots of publications, posters, lectures, etc. every year. Are you a good academic fit here? Will you be involved in these things?
So, now you've got the interview. Now what?
Do you have obvious personality disorders, communication problems, strange mannerisms, etc. Are you completely socially inappropriate? You would be surprised how many people are great on paper and bad in person. Really bad. If I don't even want to complete the interview, why would I want to work with you for a year? I wouldn't, and don't have to. Hide this stuff really well if you're dealing with these issues.
If you have supposedly done research, presentations, posters, etc. you better be able to explain what you did, intelligently, and the results. Again, you'd be surprised. It is a huge red flag for me. I used to do some research and scholarly activity back in the day. I can explain what it was about and what I did 20 years ago in medical school. If you can't explain what you did last year, you obviously didn't really do anything. How can applicants not expect this question? It's baffling.
Do your stated career goals match your history and what you want to do with us? If you say you want to be a big time academic anesthesiologist and be a future chairman and have done essentially zero research at a place with ample opportunity, that is a problem. Not our problem though.
Your ability to coherently answer "why here?" is extremely important. We want a good fit. Why do you want to be here and where do you want to go? How can we get you there? All important.
Are you faculty partner potential? If you say you want a job here, great! But are you really a good fit? Fellowship is also a year long interview. There is a reason most faculty hires come out of the fellowship.
Enough ramblings.
I wouldn't rank me if I gave this answer.
Any specific questions?
(Don't ask which residencies suck, I'm not answering that, and it should be fairly obvious. They're not surprises. Look around. Are you a horrible applicant? Are your faculty a bunch of hacks? Do you walk around wondering how y'all aren't killing more patients? If no, it's probably not your place.)