Questions on public health forms: the metadata required to describe standard data elements deployed in dynamic contexts

The desire for standardised, reusable questions has been expressed in a variety of domains, including Public Health and Emergency Preparedness and Response. Reusable questions will enable the collection of interoperable data and facilitate efficient aggregation and timely analysis. The metadata required to describe such reusable objects is multi-layered, including attributes that describe the question existing independent of any data collection context, plus metadata elements that describe its relationships to the form and its elements, the deployment of the form for data collection, and finally the context in which the question was answered. Contrary to common standard interpretation, this building and variable set of metadata does not cause the question or its underlying data element to become a different object, but rather it becomes a more refined version of the same object whose full description must be made available when the answer data is analysed.