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If data are in scope for a domain defined in this guide , but not all data can be collected using the domain's collection fields, then collection fields may be added to the applicant's CRF from the CDASH Model, the SDTM, or created by the applicant using guidance belowin the TIG.

Prior to adding fields from the CDASH Model, the SDTM, or considering a new applicant-defined collection field, confirm that none of the fields in the domain will fit the need. Fields may be added from the CDASH Model, the SDTM, or created only when data are different in nature and are not in scope for existing domain collection fields in this guide. 

Once confirmed, determine whether adding a field from the CDASH Model will fit the need. If adding a field from the CDASH Model meets the need, then a new field will not be created. New fields will only be created for when data are not in scope for a field defined in the CDASH Model. The overall process for extending metadata is as follows:Adding Fields from the CDASH Model

  1. Using the root variables and other CDASH metadata in the CDASH Model, add any additional variables that are needed to meet the requirements of data collection. Follow Appendix B, CDISC Variable-naming Fragments conventions, and CDASH

    1. Refer to both the CDASH Model and Appendix C, CDASH Model Metadata Tables.
    2. Follow CDASH root variable-naming conventions where they exist (e.g., --DAT for dates, --TIM for times, --YN for prompts, as described in the CDASH Model)


    Example: Replace "--" with the 2-character domain code that matches the other variables in the same domain. For example, to add the --LOC variable to a Medical History CRF, the domain code is MH, so the variable would become MHLOC in that domain.

    The Question Text and Prompt columns in the CDASH Model metadata provide different variations in the recommended text for asking the question on a CRF. For each question, the sponsor may elect to either use the Question Text or the Prompt on the CRF. Some text is presented using brackets [ ], parentheses ( ), and/or incorporating forward slashes. These different formats are used to indicate how the Question Text or Prompt may be modified by the sponsor.

  2. The text inside the brackets provides an option on the verb tense of the question, or text that can be replaced with protocol-specific verbiage.

  3. The text inside the parentheses provides options (e.g., singular/plural), or text that may be eliminated.

  4. Text separated with a forward slash provides optional words that the sponsor may choose.

    Example: The CDASH variable --PERF, from the CDASH Model, has the following Question Text and Prompt.

    Question Text:  [Were any/Was the] [--TEST/ topic] [measurement(s)/test(s)/examination(s)/specimen(s)/sample(s)] [performed/collected]?

     Prompt:  [--TEST/Topic] [Measurement(s)/Test(s)/Examination(s)/Specimen(s)/Sample(s)] [Performed/Collected]?

    The sponsor wants to add a question to a CRF that asks whether a lab specimen was collected, using a Yes/No response.

    The sponsor selects the CDASH variable --PERF and adds the appropriate domain code. LBPERF  

    Use either the Prompt or the Question Text on the CRF.

    Question Text: Was the laboratory specimen collected?

    • In the first set of brackets, the text option "Was the" is selected, as the study required only 1 lab test to be performed. [Were any/Was the
    • In the second set of brackets, the text used is "laboratory," which is the topic of interest. [--TEST/Topic (laboratory)]
    • In the third set of brackets, the text option "specimen," without the optional "s," is selected. [measurement(s)/test(s)/examination(s)/specimen(s)/sample(s)]
    • In the fourth set of brackets, the text option "collected" is selected. [performed/collected]

    Prompt: Laboratory Specimen Collected

    •  In the first set of brackets, the text used is the topic of interest (i.e., laboratory). [--TEST/Topic (Laboratory)
    • In the second set of brackets, the text option "specimen," without the optional "s," is selected. [Measurement(s)/Test(s)/Examination(s)/Specimen(s)/Sample(s)]
    • In the third set of brackets, the text option "collected" is selected. [Performed/Collected]
  5. Create custom domains based on 1 of the General Observation Classes in the CDASH Model. See Section 3.4, How to Create New Data Collection Fields When No CDASHIG Field Has Been Defined, for more information.

Creating New Fields

...

    1. and align with CDISC NSV Registry conventions as applicable.

  1. Select variables from the SDTM when fields from the CDASH Model cannot be used. Selection of variables must align with SDTM usage restrictions.
  2. Create a new applicant-defined collection field when fields in the CDASH Model and variables from the SDTM cannot be used.

    1. When creating a new applicant-defined collection field, determine whether the data will be used for an operational use case (e.g.,

...

    1. data cleaning

...

    1. ) or are

...

    1. to be represented in a tabulation dataset. In general, new data collection fields (not already defined in the CDASH Model) will fall in

...

    1. 1 of following categories:

...

      1. a field used for operational,

...

      1. data cleaningpurposes only

...

      1. ;

...

      1. a field used to collect data that have

...

      1. direct mappingto a target variable in the tabulation dataset

...

      1. ; or

...

      1. a field used to collect data that have

...

      1. no direct mapping to a target variable in the tabulation dataset.

    1. The following table

...

    1. provides implementation guidance aligned with both the category of the field and target variable.

Metadataspec
NumField CategoryTarget Tabulation VariableImplementation
1Data CleaningcleaningNAThe field --YN with Question Text "Were there any [interventions/events/findings]?" can be used for this purpose. Replace the two 2 dashes (--) with the two2-character domain code and create the Question Text question text or Prompt prompt using generic Question Text question text or Prompt prompts from the CDASH Model as a base. Always create custom data-cleaning/operational variables using consistent naming conventions.
2Direct MappingmappingYes

If a value can be collected exactly as it will be reported in the tabulation dataset (i.e., same value, same data type, same meaning, same controlled terminology), the tabulation variable name will be used as the data collection variable name in the operational database to streamline the mapping process.

Extensions

Characters may be appended

if

to the data collection variable name if needed to create a unique variable name in the collection database. Any collection variable whose meaning is the same as tabulation variable will align with tabulation variable and the meaning will not be modified for data collection.

3

No Direct Mappingdirect mapping


Yes

If a value cannot be collected in alignment with the tabulation dataset variable (e.g., collected data type is different from the data type in the corresponding tabulation variable) or if the tabulation variable is derived from the collected value, then the operational database should use a collection variable with a different name from tabulation variable into which it will be mapped.

No

If a field does not align with a tabulation variable, a unique name should be assigned based on applicant business rules using CDASH naming fragments (e.g., --DAT, --TIM) as appropriate and CDISC variable naming fragments, found in

Section x.x, CDISC Variable-naming Fragments, where possible. 

the CDISC NSV Registry, where possible. 

If data are not in scope for a domain in this guide, a custom domain can be used. An existing domain may help in selecting the fields and terminology needed for the custom domain. The custom domain must be based on one of the SDTM general observation classes. See Section 2.8.3 How to Create New Specifications for further information.

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