Observational study

A type of clinical study in which participants are identified as belonging to study groups and are assessed/observed for biomedical or health outcomes. Participants may receive diagnostic, therapeutic, or other types of interventions, but the investigator does not assign participants to a specific intervention/treatment (as in a clinical trial). Data are collected using questionnaires, lab tests, medical records, and historical datasets. A patient registry or a retrospective chart review are types of observational studies. NIH ClinicalTrials.gov: Glossary of Common Site Terms