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Who Conducts Research at the NIH?

Laboratories at the NIH vary greatly in size. A small lab may have only a half dozen staff members, while a large group may include thirty. A laboratory may include individuals from some or all of the following groups.

Principal Investigators: Principal investigators (PIs) hold a doctoral degree. They can be either tenured investigators (also known as senior investigators) or tenure-track investigators. These individuals run their own labs and have the authority to hire all of the remaining groups of scientists. There are about 1200 PIs at the NIH, about three-fourths of them tenured.

Staff Scientists: Staff scientists generally hold a doctoral degree. Although they are not principal investigators, they are extremely accomplished scientists. They often fulfill key functions such as managing the laboratory of an extremely busy PI or running a core facility that provides services to many investigators. About 1300 individuals are staff scientists at the NIH.

Clinical Fellows (about 400 of them) are individuals who hold a professional doctoral degree (e.g., MD or DDS), have recently completed their internships and residencies, and are at the NIH both to provide clinical services and to conduct research.

Postdoctoral Fellows: More than 3600 individuals who have recently received a doctoral degree are continuing their research training at the NIH. They are generally called Postdoctoral IRTAs (CRTAs if they are working in the NCI) if they are U.S. citizens or permanent residents and Visiting Fellows if they are citizens of another nation. Individuals can spend no more than five years as a postdoctoral fellow at the NIH. In order to stay longer, they must be promoted either to Research Fellow, a move that allows them to remain for an additional three years, or to a permanent position.

Graduate Students: The NIH is the research home for more than 480 graduate students, who are generally working towards a PhD (the NIH has only a few master's degree students). The graduate students complete their coursework at and receive their degrees from their universities and conduct all or part of their dissertation research at the NIH.

Medical Students: Medical students who have completed their core electives and who have the permission of their institutions can spend one or two years conducting research at the NIH through the Clinical Research Training Program (CRTP) or the Howard Hughes Medical Institute (HHMI) Research Scholars Program. A total of about seventy students participate in these programs each year. Medical students can also complete clinical electives at the NIH. 

Postbac Trainees have recently completed a bachelor's degree and are spending a year (sometimes two years) at the NIH conducting biomedical research while they apply for admission to graduate or professional school. There are about 700 postbacs at the NIH.

Summer Interns: Each summer about 1200 high school, college, graduate, and professional students spend eight to ten weeks working in the laboratories of the NIH Intramural Research Program. These individuals must be at least sixteen years of age and U.S. citizens or permanent residents.