I get the match results of everyone I ranked. So, if I ranked you but filled above you on the match list, then yes I would know that you didn't match. This wouldn't completely surprise me, since you were low on my list I would expect you might be low on other lists also.
If you have never applied to my program, then there is no list of unmatched applicants that gets published. An NRMP search of your record will simply be empty -- no matches, can't tell if you went unmatched, withdrew, or never even applied in the match before.
So, basically, there is no secret central list of unmatched applicants or anything like that, and most people will not be able to tell that you didn't match.
However, it will be clear that you did something other than a residency in the year after graduation. You will likely be asked about that -- "So tell me why you decided to do a year of research after graduating medical school?". At this point you have to decide to tell the truth --- "I applied and didn't match" or something else "I wasn't sure what field I wanted to go into, and I needed more time and experience to determine my best career plan". The second is not exactly truthful (but perhaps not really lying either), can be considered a "fraudulant" application (a bit of a stretch) and get you fired.
Re-applicants are of course at a disadvantage -- you are now competing with the next year's class plus those in your class that didn't match. If you don't match one year, you need to do something that makes you more competitive the next (or change fields to a less competitive field). You become 1 more year away from your med school grad and clinical experience.
Thanks KCox and especially aProgDirector for all of your helpful responses to what may seem a trivial question so far. But I assure you the match is like a black box to most of us applicants so your replies are extremely valuable.
"I get the match results of everyone I ranked. So, if I ranked you but filled above you on the match list, then yes I would know that you didn't match. This wouldn't completely surprise me, since you were low on my list I would expect you might be low on other lists also."
Are you saying the match results you get include results of people who don't match? Or are people who don't match omitted from the match results report and you are inferring that I didn't match based on your ranking of me and where you filled?
Isn't it possible for you to rank me low, fill above me, and another program X to rank me high and take me? Although I guess you are saying in this case (I match at X) you would get the report that I matched at program X.
What if you ranked me, but I never turned in a ROL? How much would you know? Would you know I didn't turn in a ROL or would you just assume I didn't match?
The corollary: it is better to formally withdraw from the match, or informally withdraw by not submitting a ROL?
"If you have never applied to my program, then there is no list of unmatched applicants that gets published. An NRMP search of your record will simply be empty -- no matches, can't tell if you went unmatched, withdrew, or never even applied in the match before."
What is this NRMP search tool? Under what scenarios does a NRMP search of my record return unempty, i.e. with information and what information precisely?
"So, basically, there is no secret central list of unmatched applicants or anything like that, and most people will not be able to tell that you didn't match."
What do you mean by "most people"?
The whole waiting 1 year + reapplicant disadvantage I understand completely. But I just wanted to make sure new programs and specialties you've never applied to can't discern that you're a re-applicant. But can #2 really be fraudulent and get you fired? That seems a bit harsh.