Well, it's been enlightening reading all these responses, but I could sit on the sidelines no longer.
As a DO who's a residency director in an allopathic program, I have a little bit of a different perspective re: COMLEX and USMLE. Board scores (either one) are only ONE factor used to determine someone's competitiveness for a residency program. Your academic record and letters of recommendation, especially from faculty members in that specialty, are going to be important as well. Doing a rotation at a program you are interested in can also help.
Even though both COMLEX and USMLE are set up as LICENSING exams, they are certainly used as ACHIEVEMENT tests. They are about the only standardized, objective measure we have to look at students (especially since so many med schools are wimping out and not providing class ranks, etc.)
Should you take both exams? Depends on what specialty you're going into and what the program wants. Since I'm fairly familiar with COMLEX, our program doesn't require DO's to take USMLE. However, in my experience, many (but not all) DO students tend to do worse (perhaps 20-25%ile points worse) on USMLE compared with COMLEX. I'm not sure of all the reasons, and I'm sure there are many. The tests are a little different, and perhaps have different emphasis. Take USMLE if you think you need to (or if the program thinks you need to). As one posting said, if you don't do well on USMLE (but did well on COMLEX) you'll be kicking yourself in the butt about it.
The emphasis with either test is to DO WELL!! If you're going into a less competitive specialty (most of primary care, for example) it probably is less important. If you're heading toward a more competitive specialty, a very strong COMLEX score will be important. 50%ile probably will not cut it in a competitive program/specialty. Also, don't think that kicking ass on your test will make up for a mediocre medical school performance (all that does it tell program directors that you are either lazy or just test well).
There is not set answer on this issue for everyone. Most program directors want residents who will work hard, get along with people, are nice, teachable, eager to learn, and have the academic ability to learn their specialty. Some residents have great board scores and are average clinicians, others have average scores and are great clinicians. The trick for us is to try to predict how people are going to turn out, and that's really a complete (or almost complete) crapshoot. Resident selection is part objective and part voodoo.
Don't know if any of this rambling has helped. Whatever one decides, you have to work hard, do well in school, do well on the exams, interview well, and study (isn't that what you mother's been telling you for 20 years?)
Good luck.
Marc Squillante, DO, FACEP
Director, Emergency Medicine Residency Program
OSF St. Francis Medical Center/ Univ. of Illinois College of Medicine @ Peoria, IL
