Due to vacations and the need to train new adcom members, my school doesn't get started reviewing applications until August. By the time we get started, there are several thousand applications stacked up. They aren't, as best I can tell, time stamped and dealt with on a first come first served basis. Mostly, you take the one at the top of the stack. In some cases, the appies with the best stats (gpa and MCAT) might rise to the top of the stack and be reviewed first (want to get those applicants here for an interview before someone else interviews them & makes an offer). There are a million reasons, including luck of the draw, why people who were complete after you were are invited for interview ahead of you. As the stack of "applications to review" grows shorter, the stack of "applicants that should be interviewed" grows taller. These applicants might be ranked and those at the top of the list are invited to interview, more are added to the list, the list is sorted again so that the highest ranked are at the top and so on. The very best applicants tend to apply early but to give all the interviews out at the beginning isn't a good strategy because there are always those late-comers who are very, very good but sometimes less well informed about the application process (many are non-trad or from small schools not known for pre-med). So, let's say we rank students from 1 to 10 and begin by inviting all the 9s and 10 for interview. Eventually, the pile is worked down such that the top of the list are 8s and 9 with the occasional 10. If you are an 8, you can expect an invitation to interview a little later than someone who was a 9. Eventually, the stack may be whittled down so that those who were reviewed early but ranked as a 7 are invited to interview later in the season.
This is a marathon, not a sprint. I will be reading applications for 5 months and interviewing applicants for 6 months. Applying early has become more and more common and we now have on hand about 67% of all the applications we expect to see this year. Obviously, it is going to take a long time to work through that stack, and more are added to it every day!
For those of you who ask why I'm here rather than reading more appies 😛 ; I discovered long ago that I can't do more than a couple hours of that work per day (it is in addition to my "day job") without becoming cynical or having all the applicants blend together. Everyone gets a fairer shake if I take it slow.
One more thing... Even if we had already identified the first 300 whom we'd like to interview from among the early applicants, if we start offering interviews now for November and December we'd be fielding a lot of phone calls from people who need or want to reschedule either now or closer to the date. I think tha the office has found it much more efficient to offer interviews a month or 6 weeks in advance but not much more than that.
Good luck to everyone.