While U.S. institutions do not award higher doctorates, many persons who have earned Ph.D.s or similar degrees apply to and enroll in postdoctorate research programs or internships.

Such programs are especially frequent in the health and medical sciences, the counseling professions, and the natural sciences. Postdoctorate programs take place at universities, hospitals and clinics, research facilities in government and industry, and museums. They may last one or more years.

Academic credit toward further degrees is not usually earned, but the programs are often significant additions to an individual's professional resume and credentials.