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NIH Clinical Trials Definition

In 2014, NIH’s definition of a clinical trial was revised in anticipation of stewardship reforms. Recently, NIH launched a multi-faceted effort to enhance its stewardship over clinical trials with the goal to encourage advances in the design, conduct, and oversight of clinical trials while elevating the entire biomedical research enterprise to a new level of transparency and accountability.

Everyone who proposes or participates in conducting NIH-funded research with human participants must consider whether their studies meet the NIH clinical trial definition:

  • A research study1 in which one or more human subjects2 are prospectively assigned3 to one or more interventions4 (which may include placebo or other control) to evaluate the effects of those interventions on health-related biomedical or behavioral outcomes.5
  1. See Common Rule definition of research at 45 CFR 46.102(d).
  2. See Common Rule definition of human subject at 45 CFR 46.102(f).
  3. The term prospectively assigned refers to a pre-defined process (e.g., randomization) specified in an approved protocol that stipulates the assignment of research subjects (individually or in clusters) to one or more arms (e.g., intervention, placebo, or other control) of a clinical trial.
  4. An intervention is defined as a manipulation of the subject or subject’s environment for the purpose of modifying one or more health-related biomedical or behavioral processes and/or endpoints. Examples include: drugs/small molecules/compounds; biologics; devices; procedures (e.g., surgical techniques); delivery systems (e.g., telemedicine, face-to-face interviews); strategies to change health-related behavior (e.g., diet, cognitive therapy, exercise, development of new habits); treatment strategies; prevention strategies; and, diagnostic strategies.
  5. A health-related biomedical or behavioral outcome is defined as the pre-specified goal(s) or condition(s) that reflect the effect of one or more interventions on human subjects’ biomedical or behavioral status or quality of life. Examples include: positive or negative changes to physiological or biological parameters (e.g., improvement of lung capacity, gene expression); positive or negative changes to psychological or neurodevelopmental parameters (e.g., mood management intervention for smokers; reading comprehension and /or information retention); positive or negative changes to disease processes; positive or negative changes to health-related behaviors; and positive or negative changes to quality of life.

If the answers to all the questions below are “yes,” the study meets the definition of a clinical trial (NIH Clinical Trial Decision Tree):

  • Does the study involve human participants?
  • Are the participants prospectively assigned to an intervention? 
  • Is the study designed to evaluate the effect of the intervention on the participants?
  • Is the effect that will be evaluated a health-related biomedical or behavioral outcome?
Last Updated Date: 
January 11, 2018