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The date, and time as applicable, of an observation to be related to a reference will be collected whenever possible. Only in cases where it is not possible to collect the date of a related observation (e.g., the date is not available), will a relative timing for the observation in relation to a reference be collected. Relative timing will be collected using TIG collection variables

• --PRIOR to indicate the timing of the observation was prior to the start date of a reference period or the date of a reference time point; or
• --ONGO to indicate the timing of the observation was ongoing relative to the end date of a reference period or the date of a reference time point.

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