Physicians who move and why they move.

Physicians in the United States migrate across county lines more often than nonphysicians, but their migration parallels that of the population at large: from the northern "Frost Belt" to the southern "Sun Belt." The data presented herein show that mobile physicians ("movers") are more often younger and female than nonmobile physicians ("stayers"). Stayers are more likely to be primary care of self-employed physicians, and movers more often are in nonprimary care or in medical administration, research, teaching, or other medical employment modalities. County-level characteristics such as population income and size also help determine whether a physician will be a mover or stayer.