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NIH definition of a Clinical Trial

The NIH definition of a clinical trial is very broad. Some investigators conducting human subjects research may not be aware that NIH considers their study to be a clinical trial. Correctly identifying whether a study is considered by NIH to be a clinical trial is crucial to how investigators will:

  • Select the right NIH funding opportunity
  • ensure your application includes all the information required for peer review
  • comply with the appropriate policies and regulations

NIH Definition of a Clinical Trial: A research study in which one or more human subjects are prospectively assigned to one or more interventions (which may include placebo or other control) to evaluate the effects of those interventions on health-related biomedical or behavioral outcomes.

The NIH has developed case studies to illustrate the differences between clinical trials and clinical studies using the following four questions:

  1. Does the study involve human participants?
  2. Are the participants prospectively assigned to an intervention?
  3. Is the study designed to evaluate the effect of the intervention on the participants?
  4. Is the effect being evaluated a health-related biomedical or behavioral outcome?

For more information, see grants.nih.gov/policy/clinical-trials/case-studies.htm and grants.nih.gov/policy/clinical-trials/definition.htm.