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1. Similarly, where SDTMIG variables exist in the operational database and the value conforms to controlled terminology, it is permissible to use a familiar synonym on the CRF without affecting conformance. For example, on the Demographics page, SEX may be displayed as "Male" or "Female", whereas in the operational database the controlled terminology values of "M" and "F" would be used.
2. In some cases, CDASH Question Text and Prompt allow for flexibility while still being considered conformant. See Section 2.3, CRF Development Overview, for further details on the usage of Question Text and Prompt.
3. CDASH Model Question Text may contain options for the tense; if the option is not provided, the tense of the Question Text may be modified to reflect the needs of the study.
4. In cases where the CDASH Question Text or Prompt cannot be used due to culture or language, or a CRF must be translated for language or cultural reasons, the implementer must ensure the translation is semantically consistent with the CDASH Question Text and Prompt in the CDASHIG metadata table.
5. In cases where a more specific question needs to be asked than that provided by Question Text or Prompt, CDASH recommends the use of a brief CRF Completion Instruction, as long as the instruction clarifies the data required by the study without altering the meaning of variable as defined by the standard. For example, "Sex at birth" is not the same question as "Sex" (which is loosely defined as "reported sex").

Best practices - variable naming

1. Use a consistent syntax that includes the root variable name and/or controlled terminology, and any other standardized concepts that are needed to support efficient mapping of the collected value to SDTM datasets. The goals are to have beginning-to-end traceability of the variable name from the data capture system to the SDTM datasets, and to support automating electronic data capture (EDC) set-up and downstream processes.

   1. It is recognized that (particularly in an EDC system) the variable name of a data collection field, as well as the name in the underlying database, may have various “system” components that become part of the item’s identifier. EDC systems, prior to exporting data in a defined format, may require the variable name to include such database “references” as the EDC page name, the item “group” name, or perhaps a combination.

   2. In cases where the data collection is done in a denormalized way, appropriate CDISC CT must be used when it is available.

      1. For example, when collecting vital signs results in a denormalized eCRF, the variable names can be created by using terms from the Vital Signs Test Code codelist. For example, temperature result can be collected in a variable called TEMP or TEMP_VSORRES; systolic blood pressure result can be collected in a variable called SYSBP or SYSBP_VSORRES. When a particular system’s constraints limit the variable name to 8 characters, a similar, consistent implementation that preserves either the normalized root variable (e.g., ORRES) or the controlled terminology (e.g., --TESTCD value) should be implemented.

      2. Other variable patterns that intentionally connect the data collection variable to the target SDTMIG variable are also acceptable.  For example, targetDataset_targetVariable[_optionalTopic] is acceptable. Examples of this pattern include DM_AGE, DM_AGEU, VS_VSORRES_TEMP, VS_VSORRESU_TEMP, SUPPAE_QVAL_AEDIS.

   3. Whereas all CDASHIG defined variable names are 8 characters or fewer to accommodate SDTM limits on variable names, QNAMs, and --TESTCDs, the maximum length of a variable name that may be implemented is determined by the data management system used, not by CDASH. 

   4. When collecting data in a horizontal manner, to facilitate transformation to SDTM datasets, when possible it is recommended to create denormalized CDASH variables in the data collection system by incorporating the SDTMIG variable name target and/or the controlled terminology (e.g., --TESTCD) as part of the CDASH variable names. The domain-level metadata labeled as "Horizontal-Generic" in the Implementation Options column of the CDASHIG metadata tables are examples of how to implement this. There is no conformance requirement implied by these examples.

Relative Timing Variables (SEE SECTION 3.7)

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