Human subject research is systematic, scientific investigation that can be either interventional (a "trial") or observational (no "test article") and involves human beings as research subjects, commonly known as test subjects. Human subject research can be either medical (clinical) research or non-medical (e.g., social science) research. Systematic investigation incorporates both the collection and analysis of data in order to answer a specific question. Medical human subject research often involves analysis of biological specimens, epidemiological and behavioral studies and medical chart review studies. (A specific, and especially heavily regulated, type of medical human subject research is the "clinical trial", in which drugs, vaccines and medical devices are evaluated.) On the other hand, human subject research in the social sciences often involves surveys which consist of questions to a particular group of people. Survey methodology includes questionnaires, interviews, and focus groups.
Human subject research is used in various fields, including research into advanced biology, clinical medicine, nursing, psychology, sociology, political science, and anthropology. As research has become formalized, the academic community has developed formal definitions of "human subject research", largely in response to abuses of human subjects.
The United States Department of Health and Human Services (HHS) defines a human research subject as a living individual about whom a research investigator (whether a professional or a student) obtains data through 1) intervention or interaction with the individual, or 2) identifiable private information (). (Lim, 1990)
As defined by HHS regulations ():
Intervention – physical procedures by which data is gathered and the manipulation of the subject and/or their environment for research purposes.
Interaction – communication or interpersonal contact between investigator and subject.