Alternative Representation of Non-Standard Variables

8.4.4.1   Background

As an alternative to submitting non-standard variables (NSVs) in separate SUPP-- datasets, they may be represented in the parent datasets. This method provides some additional benefits. These include the following:

• Permitting direct viewing of standard variables and NSVs within the same structure, eliminating the need for tools or the writing of programs to display the data together.
• Eliminating some current SUPP-- structural limitations by allowing:
  • Numeric NSVs to be represented in a numeric data type
  • Character NSVs to be defined with an appropriate length for each variable, rather than the typical default of $200 for QVAL
  • Allowing metadata for NSVs (including Controlled Terminology) to be applied at the variable level instead of the value-level.

8.4.4.2   Implementation Rules

In order to use the alternative described above, the following implementation rules must be followed:

• The list domains to which NSVs may be added does not change. NSVs may be added only to general-observation-class domains and Demographics.
• The same considerations must be used in assessing the number of NSVs represented, regardless of whether they are represented in SUPP-- datasets or in the parent domains. In other words, sponsors must not seek this implementation as a method for representing NSVs that would not have previously been represented in SUPP-- datasets.
• Complete metadata must be provided for each NSV in the same way it’s required for standard variables.
• Variable lengths for character NSVs should be set to the appropriate length for that variable, as with all standard character variables.
• Metadata roles for NSVs are defined appropriately, based upon the SDTM variables roles, and must be one of the following Roles:
  1. Non-Standard Identifier
  2. Non-Standard Qualifier, further categorizable into:
     
     • Non-Standard Grouping Qualifier
     • Non-Standard Result Qualifier
     • Non-Standard Synonym Qualifier
     • Non-Standard Record Qualifier
     • Non-Standard Variable Qualifier
  3. Non-Standard Timing
• NSVs would be ordered after the standard variables, and ordered as shown in the bullet above. The order within each of the non-standard Roles should be consistent within the dataset and the define.xml.

Example

This is an example of hospitalization data with non-standard variables.

This example shows three hospitalization records, two for Subject 0001, and one for Subject 0002. In the collected data, there are standard variables from the SDTM: Identifiers from Table 2.2.4, Event Qualifiers from Table 2.2.2 of the SDTM, Timing variables from Table 2.2.5. In addition, there are the following non-standard variables:

Two methods are shown for the representation and submission of these data: the method of submitting NSVs in SUPPHO and the new method of submitting NSVs in the parent domain.

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