A group of individuals sharing one or more characteristics that are observed during a designated time period. (HRSA/OPTN Patient Glossary, June 2026)
A group of candidates, recipients, or donors from a specified time-frame (also called a reporting period or observation period). (SRTR Definitions, June 2026)
A population group that shares a common property, characteristic, or event, such as a year of birth or year of marriage. The most common one is the birth cohort, a group of individuals born within a defined time period, usually a calendar year or a five-year interval. (CMS Glossary, June 2026)