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The following guidance...

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ForCategoryGuidance
CRF and System DesignCollection of Dates

  • Implement collection of dates such that individuals involved in data can only record the data to precision collected. 

    • The system should also store only the collected precision.

    • Any incomplete dates must remain incomplete with no imputation and no “zero-filling” of missing components.

    • Data collection and database processes should allow for the possibility of partial dates and times, because a partial date may be the most precise information that can be collected for some data. 

      If a full date is collected (or expected), the CDASH variable --DAT or all 3 date components (i.e., --DATYY, --DATMO, --DATDD) should be included on the collection tool. If a partial date can be collected in a single field, the CDASH --DAT should be used. If a partial date must be collected as separate database fields to collect year, month, and day, refer to the CDASH Model for examples of standard naming fragments (--YY, --MO, --DD, --TIM).

    • The capabilities of individual software systems (e.g., EDC) will determine which variable names are needed. CDASH uses separate data collection fields for dates and times. 

Tabulation Dataset Mapping

Collection Guidance






Imputation of Dates

The visit date variable (VISDAT) can be applied to all observations for a given visit (if appropriate), or specific date and timing fields may be included for a specific observation in the body of the CRF. When the visit date is used to reflect the timing of an observation, the appropriate timing variable for that tabulation dataset may be populated with the CDASH Visit Date. 

Relative Timing Variables (SEE SECTION 3.7)

Relative timing variables are sets of variables that provide information about how the timing of the record relates to either the study reference period or another fixed point in time. CDASH relative timing variables are collected for observations where a date either is not collected or is not available. The CDASH set of variables serve as an indicator (or flag) that the observation's "start" was prior to the study reference period or prior to another fixed point in time OR that the observation's "end" was after or ongoing as of the study reference period or another fixed point in time. The CDASH variables of --PRIOR and --ONGO serve this purpose. How these CDASH flags are translated to SDTM (according to controlled terminology) depends on whether the comparison is against the protocol-defined study reference period or against another fixed point in time serving as the "reference" for the timing of the record. To emphasize, collection of these CDASH relative timing variables is always dependent on the actual date either being prospectively not collected or not available. For more information, see Section 8.1.1, General CDASH Assumptions for Interventions Domains, and Section 8.2.1, General CDASH Assumptions for Events Domains.

For all SDTM submissions, there is a defined timeframe (the study reference period). According to SDTMIG, the start and end dates of the study reference period are submitted in the variables RFSTDTC and RFENDTC. The defined period may be protocol-specific or set by company policy, standard operating procedures, or other documented procedures. The study reference period might be defined as being from the date/time of informed consent through the date/time of subject's completion of the study, or it might be from the date/time of first dose to the date/time of last dose. Regardless of how the study reference period is defined, the dates (and optionally times) of the start and end of that period must be collected.

If there is a need to collect information about whether an observation of interest occurred prior to a reference point or milestone other than the beginning of the study reference period, or was ongoing or continuing at some reference point or milestone in the study other than the end of the defined study reference period, the date/time of that reference point or milestone should also be collected. If this date/time has been collected, reasonable comparisons can be made to that date/time with “prior”, “coincident”, “continuing”, or “ongoing” questions.

Study reference period figure

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