Originally posted by Intrepidation:
•If this is true, what steps should I take in order to ensure that I can go to my top choices?•
Although I'm only a lowly MS1, I'll take a stab at part of your question.
Basically, you'll have a meeting by either the end of your 3rd year, or the beginning of your 4th year, with a Dean from your medical school who's main focus is helping MS4's through the Match, and writing the infamous "Dean's Letter" -- basically a stamp of approval from your med school that you are a good candidate. A line or two will reflect your work in the basic sciences, and then the rest of the letter will be devoted to your clinical rotations, how well you did, excerpts from your clinical evaluations, etc., and also some of the letter may discuss your extracurriculars if they are particularly noteworthy (ie, started some new organization at the school, etc.). Obviously, some letters are stronger than others, based on the candidate's credentials.
Anyways, when you have this meeting with the Dean, you discuss the field you would like to match into, and some of the programs you are interested in. The Dean, based on the match results of previous MS4's at your school, will tell you if your plans are realisitic or not. If you've been a really mediocre student all through med school and have really average board scores, but want to go into Derm or another highly competitive area, the Dean will most likely politely discorage you from this, because the reality is that you would not be a competitive candidate. Same with certain locations -- residencies in Boston (esp. those affiliated with Harvard), New York, and most places in California, tend to be very competitive to place into, based on sheer location. Basically, no matter what area of medicine you want to go into, there are competitive programs in each, and if you are not a competitive candidate, the Dean will discourage you from applying to those programs.
As for what you can do to ensure that your top choices are available to you, my only suggestion would be to work as hard as you can from Day 1. Basically, I have no idea what I want to do at this point, but I really don't want to have certain doors closed to me in 4 years, so I'm going to try to do as well as I possibly can the next 4 years. Med school is extremely time-consuming and draining, much more so than I expected (as least basic sciences-wise), so I know that this won't be easy. If I meet my expectations, great, and if I don't, as long as I knew that I worked as hard as I could, then I'll be okay with that.
In addition to your academics, once you are an MS4, most med schools let you take up to 3 months of away rotations at other hospitals. This may be a good way to check out a program and see if you like, and obviously if you perform well, to get a good recommendation from that program. However, I'm sure there are older and wiser med students in their clinical years, and residents, who can say more definitively how helpful this practice is in terms of matching.