This section describes how the SDTM will be implemented to describe relationships between records in the same dataset and between records in different datasets.
When applicable, variables IDVAR and IDVARVAL represent variables and values used as record-level keys to merge/join records between datasets.
In such cases, IDVAR and IDVARVAL the names of variables and specific variable values which relate records by acting as
The following are examples of variables that could be used in IDVAR:
- Variables with values unique to each observation. When possible, variables with values from collected data are used (e.g., SPID, RECID), but variables with derived values may also be used (e.g., --SEQ).
- When relationship datasets (e.g., SUPPxx, FAxx, CO, RELREC) relate back to split parent domains, the value of IDVAR will be from a variable with unique values for each observation.
When possible, the variable represented in IDVAR will have values from collected data
- Variables from collected data
- The Sequence Number (--SEQ) variable uniquely identifies a record for a given USUBJID within a domain. The variable --SEQ is required in all domains except DM. For example, if a subject has 25 observations in the Vital Signs (VS) domain, then 25 unique VSSEQ values will be populated for the subject.
- The Reference Identifier (--REFID) variable can be used to capture an applicant-defined or external identifier, such as an identifier provided in an electronic data transfer.
- The Grouping Identifier (--GRPID) variable, used to link related records for a subject within a domain.
Overview
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