Existing Wording: This resource covers two major use-cases:

Definitions of types of measurements or observations that may be requested or performed. In HL7, these are sometimes referred to as service, test or observation "master files"

Definitions of "data elements" (DEs) that may be used in questionnaires (survey instruments and data collection forms) and profiles and potentially mapped to elements in other resources and profiles

The purpose of the first use-case is to allow systems to identify what types of lab orders, diagnostic studies and other types of observations may be requested or performed within a particular organization or other context. An ordering practitioner can query for a list of data elements by category name or other criteria and identify which, within a set of similar tests, they wish to request to be performed.

Comment:

This definition of Data Element concerns me. The second use case is what I typically associate with Data Element. However, the first use case is far broader than a data element and overlaps with Activity Definition I believe.

When it comes to Orderable Catalog Items, a Data Element is insufficient to represent such artefacts. I would suggest establishing a clear boundary between Data Element and Activity Definition or perhaps clarify the documentation.

Summary:

DataElement definition is problematic