Representing Planned and Actual Timing

Product Impact on Individual Health Only:

Protocols define visits to describe the timing of assessments and procedures. For planned visits:

• Values of VISIT, VISITNUM, and VISITDY will be represented as defined in the Trial Visits (TV) dataset. 
• Values of VISITNUM are:
  • Expected when observations in a domain have been collected more than once per subject (e.g., vital signs in domain VS when collected for subjects over multiple visits).
  • Used for sorting and will, wherever possible, match the planned chronological order of visits.
• For visits that last more than 1 calendar day, VISITDY will be the planned day of the start of the visit.

 For unplanned visits, applicant practices for populating visit variables can vary:

• VISITNUM will generally be populated, as it may be expected in a domain and will be populated time points are represented.
  • The easiest method of populating VISITNUM for unplanned visits is to assign the same value (e.g., 99) to all unplanned visits, although this method provides no differentiation between the unplanned visits and does not provide chronological sorting.
  • Methods that provide a one-to-one relationship between visits and values of VISITNUM, that are consistent across domains, and that assign VISITNUM values that sort chronologically require more work and must be applied after all of a subject's unplanned visits are known.
• VISIT can be left null or may be populated with a generic value (e.g., "Unscheduled") for all unplanned visits, or individual values may be assigned to different unplanned visits.
• VISITDY will not be populated for unplanned visits; VISITDY is, by definition, the planned study day of visit. 

Nonclinical Only:

Nonclinical studies are conducted in the context of a planned study schedule. The unscheduled flag (--USCHFL) variable is populated when the timing of a performed test or observation was not driven by the study schedule. In such cases, the value of --USCHFL will be "Y".

Product Impact on Individual Health Only:

Values in EPOCH reflect study-design and will be populated for observations that start during a subject's study participation. Values of EPOCH are generally derived and will not be imputed. Values of EPOCH will be derived using collected dates. However, when this is not possible, EPOCH may be assigned per data collection sources (e.g., CRF instructions and structure). If it is not possible to determine the epoch of an observation, then the value of EPOCH will be null.

When EPOCH is included in:

• A Findings class domain, its value be based on the --DTC variable, since this is the date/time of the test or, for tests performed on specimens, the date/time of specimen collection.
  • An unlikely exception may be a finding based on an interval specimen collection that started in one epoch but ended in another. In such cases, --ENDTC may be a more appropriate for EPOCH.
• An Interventions or Events class domain, EPOCH will be based on the --STDTC variable, since this is the start of the intervention or event.