Evidence-appraisal glossary
Post-market surveillance
Post-market surveillance is the ongoing monitoring of a drug or device's safety and performance after it is approved and in general use. It can detect rare or delayed harms that pre-approval trials were too small or too short to reveal.
Also called: pharmacovigilance, phase IV surveillance.
Methods include spontaneous adverse-event reporting, registries, and analyses of real-world data across large populations over long stretches of time. Because these data are observational and reporting is incomplete, surveillance signals raise hypotheses rather than confirm cause, and a lack of reports is not proof of safety. It complements trial evidence by watching how a product behaves in everyday practice.
This is a plain-language methodology definition for reading research. It is general education, not medical advice.