There was a time when undergraduate medical education was circumscribed, neatly packaged within a single institution, and clearly identified for all to see. A student who wished to become a physician applied for admission to a medical school, was admitted, attended for four years, and graduated with an MD degree. Every student was much like every other in that he took the same courses, passed the same examinations, and could be considered to have essentially the same knowledge and skills as his classmates at the end of each year of the four-year program.
Perhaps this pattern is still true for the majority of medical students and medical schools. But for many it is not true, and the number is likely to grow substantially in the coming years. At some institutions it is possible for a student to take traditional medical school basic science courses such as biochemistry and microbiology while