CDISC-Gloss – A single observation associated with a subject in a clinical study. A data element in an eCRF represents the smallest unit of observation captured for a subject in a clinical investigation. NOTE: Examples include birth date, white blood cell count, pain severity measure, and other clinical observations made and documented during a study. Data element identifiers should be attached to each data element as it is entered or transmitted by the originator into the eCRF. See also eCRF, data element identifier, data originator, item. [After FDA Guidance for Industry Electronic Source Data in Clinical Investigations, Body text and Glossary]