The previous approach in QI-Core was to capture all requirements needed for measure or clinical decision support (CDS) use cases at the profile and element level such that any implementer could look at QI-Core to determine all elements that must be supported if measure or CDS expressions asked for them. Further authors of measures or CDS artifacts who restricted their expressions to only Must Support elements could have some assurance that respective data could be retrieved.  Given that no implementer systems have any conformance testing to QI-Core Must Support elements and there is no clear regulatory requirement for such conformance, there is no real assurance that such items are truly retrievable. Therefore this tracker and many others will specifically request the QI-Core profiles "go back to basics" and merely use the US Core profiles of the respective US Core version. The approach allows implementers to use the respective measures (or CDS artifacts) as the guide to what "non-standard" elements the measure requires - noting that each FHIR-based measure includes a listing of all required data element for that measure.

Plan is to create a specific tracker for each of the QI-Core profiles that currently build on US Core profiles rather than inheriting them as-is and reference them in this tracker for ease of finding them and their resolution.  Thus, this is the higher-level rationale for each of the respective profile-related trackers.