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The value is a data value type and is expressed as a data value widget. A value is required unless a Null flavor is set.
Null flavor
A null flavor is a textural value (DV_CODED_TEXT) from an openEHR value set which expresses the reason why the value is omitted. This would usually only be present if the ELEMENT was mandatory and had to be present. The default behaviour of openEHR is to omit data points that are not mandatory and not populated.
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