Types of Human Subjects Research

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Analysis of Existing Data or Specimens

If you're using private information, data, or specimens, your research may be exempt from the Code of Federal Regulations 45 Part 46. You may refer to the NIH Office of Extramural Research (OER) decision tool or consult with your institutional review board (IRB) or independent ethics committee (IEC). The NIDCR evaluates each project independently to determine oversight needs and whether the NIDCR Clinical Terms of Award (CToA) applies.

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 assigning participants to a specific intervention or treatment. These studies may focus on observation of risk factors, natural history, variations in disease progression or disease treatment without delivering or assigning 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

The NIH defines an intervention as a manipulation of 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 further defines a clinical trial as 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.

Toolkit for Interventional Studies

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Last Reviewed
June 2022