Does your Human Subjects Research Study Meet the NIH Definition of a Clinical Trial?

Use this tool to help determine if your research meets the NIH definition of a clinical trial. Identifying whether your study is a clinical trial is important for picking the right NIH funding opportunity, ensuring your application includes all the information required for peer review, and complying 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 prospectively assigned 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. to one or more interventions interventionsAn "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. (which may include placebo or other control) to evaluate the effects of those interventions on health-related biomedical or behavioral outcomes. health-related biomedical or behavioral outcomes.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. Learn more

Answer a few simple questions below to help determine if your study is a clinical trial

  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?

Note that if the answers to the 4 questions are yes, your study meets the NIH definition of a clinical trial, even if…

  • You are studying healthy participants
  • Your study does not have a comparison group (e.g., placebo or control)
  • Your study is only designed to assess the pharmacokinetics, safety, and/or maximum tolerated dose of an investigational drug
  • Your study is utilizing a behavioral intervention

* Basic Experimental Studies with Humans (BESH) use an intervention in order to understand fundamental aspects of a phenomena without specific application towards processes or products in mind. See here for more information.

Studies intended solely to refine measures are not considered clinical trials.
Studies that involve secondary research with biological specimens or health information are not clinical trials.

To learn more about the considerations for each question, use the decision tool below:

Note for ancillary studiesAn ancillary study is an adjunctive or supplemental study to an ongoing study. An ancillary study may or may not be a clinical trial. Determine whether an ancillary study is a clinical trial by answering the four questions that define NIH clinical trials based on the information about the ancillary study alone, regardless of the clinical trial status of the parent trial. An ancillary clinical trial is a trial for which the answer to the four questions is ‘Yes’.:
When answering the following questions, take into account only the work being proposed in the ancillary study, not the work being done in the parent project.

1. Does the study involve human participants?

Unsure how to respond? Our case studies and FAQs may help you decide.