Subject Elements describes the actual order of elements that were traversed by the subject, together with the start date or start date and time and end date/time for each. Planned elements are described in the Trial Design Model (see Section 5.1.1, Trial Arms and Trial Elements). Because actual data does not always follow the plan, the SDTM allows for descriptions of an unplanned element for subjects (SEUPDES).

See the implementation guides for further guidance regarding use of additional identifier and timing variables.

Subject Elements—One Record per Actual Element per Subject