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The CDISC SDTM can be implemented for tobacco product studies using the domain specifications in the following sections:

All specifications begin with a table to describe the domain's variables and their attributes. A domain specification table includes rows for all required and expected variables for a domain and for a set of permissible variables. There is one row for each variable with columns to describe expected attributes of the variable in resulting datasets.  The columns of in a domain specification table are:

ColumnDescription






  • The Variable Name column specifies the name of the variable; in other words, the name of the column of the dataset (e.g., "STUDYID").
  • The Variable Label column specifies a descriptive label for the variable (e.g., "Study Identifier").
  • The Type column specifies the data type of the variable. This must be "Num" for numeric data and "Char" for character (or alphanumeric) data.
  • The Controlled Terms, Codelist, or Format column specifies any controlled terminology or formats that apply to the variable. Controlled lists are surrounded with parentheses (e.g., "(BWTESTCD)" for the BWTESTCD Controlled Terminology Codelist). When a fixed value (e.g., the value for the DOMAIN variable) applies, the available value will be displayed (e.g., "BW"). When a format applies, the name of the format will be displayed (e.g., "ISO 8601" for the ISO 8601 date format).
  • The Role column specifies the role of the variable (see Section 2.4, Observations and Variables).
  • The CDISC Notes column specifies details about the proper use of the variable (e.g., description of the variable's purpose, intended use, rules governing its population, example values).
  • The Core column specifies whether the variable is "Req" (required), "Exp" (expected), or "Perm" (permissible); (see Section 4.1.3, Core Variables).

A domain specification table includes rows for all required and expected variables for a domain and for a set of permissible variables. The permissible variables do not include all the variables that are allowed for the domain; they are a set of variables that the SDS Team considered likely to be included. The columns of the table are:

  • Variable Name
    • For variables that do not include a domain prefix, this name is taken directly from the SDTM.
    • For variables with a "--" placeholder in the SDTM, the "--" is replaced by the 2-character domain code.
  • Variable Label: A longer name for the variable  
    • This may be the same as the label in the SDTM, or it may be customized for the domain.
    • Sponsors should create an appropriate label if they include in a dataset an allowable variable not in the domain specification.
  • Type: One of the 2 SAS datatypes, "Num" or "Char".  These values are taken directly from the SDTM.
  • Controlled Terms, Codelist, or Format
    • Controlled Terms
      • As noted in the table note, an asterisk (*) indicates that the variable may be subject to controlled terminology.
        • The controlled terminology might be of a type that would inherently be sponsor-defined.
        • The controlled terminology might be of a type that could be standardized, but for which a codelist not yet been developed.
        • The controlled terminology might be terminology specified in value-level metadata.
      • The name of an external code system (e.g., MedDRA) will be listed in plain text.
    • Codelist 
      • A hyperlinked codelist name in parentheses indicates that the variable is subject to the CDISC Controlled Terminology in the named codelist.
      • Multiple hyperlinked codelist names indicate that the variable is subject to 1 or more of the named codelists from CDISC Controlled Terminology. If multiple codelists are in use for a single domain, value-level metadata would indicate where each codelist is applicable.
      • A hyperlinked codelist name and an asterisk (*) indicate that the variable is subject to either the named codelist from the CDISC Controlled Terminology or to an external dictionary. The specific dictionary is identified in the metadata.
    • Format: "ISO 8601 datetime or interval" or "ISO 8601 duration" in plain text indicates that the variable values should be formatted in conformance with that standard.
  • Role: This is taken directly from the SDTM. Note that if a variable is either a Variable Qualifier or a Synonym Qualifier, the SDTM includes the qualified variable, but SDTMIG domain specifications do not.
  • CDISC Notes may include any of the following:
    • A description of what the variable means
    • Information about how this variable relates to another variable
    • Rules for when or how the variable should be populated, or how the contents should be formatted
    • Examples of values that might appear in the variable. Such examples are only examples, and although they may be CDISC Controlled Terminology values, their presence in a CDISC Note should not be construed as definitive. For authoritative information on CDISC Controlled Terminology, consult https://www.cancer.gov/research/resources/terminology/cdisc.
  • Core: Contains 1 of the 3 values—"Req", "Exp", or "Perm"—explained further in Section 4.1.5, SDTM Core Designations.


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