Page History

A domain is a grouping of observations that are related while a dataset is the data structure associated with that grouping of observations. 

In most cases there is a one-to-one relationship between a conceptual domain and a dataset based on that domain, the words are used interchangeably in the standards and, therefore, by most users. The structures called “relationship datasets” were given that name because they are mechanisms for connecting information represented in different datasets rather than observations about study subjects. Note that none of the relationship datasets includes.

However, in a submission, these datasets need dataset names, and character strings used in those names are included in the CDISC Codelist called "SDTM Domain Abbreviations."

In conclusion, there is a clear distinction between the meaning of "domain" and "dataset" but given that the naming conventions are the same across both terms, in many cases they can be considered interchangeable.

SDTM

Each domain dataset is distinguished by a unique, 2-character code that should be used consistently throughout the submission. This code, which is stored in the SDTM variable named DOMAIN, is used in 4 ways: as the dataset name, as the value of the DOMAIN variable in that dataset, as a prefix for most variable names in that dataset, and as a value in the RDOMAIN variable in relationship tables (see Section 8, Representing Relationships and Data).

...