The origins, history, and design of the resident match.

In the early 1900s, competition among hospitals for interns and among medical students for good internships led to increasingly early offers of internships to students. By the 1940s, appointments were often made as early as the beginning of the junior year of medical school. Hospitals thus had little information about students' performance, and students frequently had to make a final decision to accept or reject an offer without knowing which other offers might be forthcoming. From 1945 through 1951, efforts were made to enforce a uniform date for accepting offers. However, students were still faced with offers having very short deadlines, compelling them to accept or reject offers without knowing what other offers might be forthcoming. Hospitals often had to scramble for available students, since if an offer was rejected, it was often too late for them to reach their next preferred candidate. A centralized clearinghouse was thus developed as a way of alleviating this chaos and allowing a larger role to the preferences of both students and hospitals. This evolved into the current matching program, whose algorithm continues to be updated to take account of changing needs of applicants, such as growth in the number of couples who seek 2 positions in the same vicinity.