Types of Human Subjects Research

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Analysis of Existing Data or Specimens

If you're using coded private information, data, or specimens, NIH will consider your research to involve human subjects unless it meets both of the following conditions:

  • You are not collecting samples by interacting or intervening with living people.
  • None of the investigators, collaborators, or co-authors have access to any information (data or biospecimens) that can re-identify subjects.

Toolkit for Analysis of Existing Data

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Observational Studies

In an observational study, the investigator simply records observations and analyzes data, without administration of an intervention or alteration of the care people receive. These studies may focus on risk factors, natural history, variations in disease progression or disease treatment without delivering an intervention. They often assess specific health characteristics of the enrolled human subjects by collecting medical/dental history, exposure, or clinical data; obtaining biospecimens (e.g., for biomarker or genomic analyses); or obtaining photographic, radiographic or other images from research subjects.

Toolkit for Observational Studies

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Interventional Studies

In an interventional study, the investigator manipulates the subject or the subject's environment for the purpose of modifying one or more health-related biomedical or behavioral processes and/or endpoints. The NIH defines a clinical trial as a research study in which one or more human subjects are prospectively assigned to one or more interventions.

Toolkit for Interventional Studies

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Last Reviewed on
February 2018