I have questions regarding implementation of equivalent eCQM and QPP measures. It is my understanding that CQMs implemented as eCQMs (e.g., in CQL) and specified as QPPs (in published specifications) are supposed to be equivalent measures. For example, regarding CMS 68 ("Documentation of Current Medications in the Medical Record") and QPP 130 (same title), the intention appears to be these two measures should have the same basic implementation, resulting in the same populations etc. The same can be said of the other eCQMs and their equivalent QPP specifications.

Putting aside differences in reporting requirements and possibly, the differences in value set definition for the eCQM vs the QPP specifiction, my first question is how to handle possible differences between two measures when the age requirement for the Initial Population/Denominator differs in implementation vs specification. Specifically, the specification for QPP 130  states the age requirement in the Denominator Criteria as follows: "Patients aged ≥ 18 years on date of encounter". However, the CQL implementation of CMS 68 requires the patient be age 18 at the start of the measurement period (not at the date of the encounter). This difference was reported by one of our users and implies the two measures when properly implemented would have different denominator populations (that is the CMS 68 CQL implementation cannot be used as a basis for implementation of QPP 130). Consider this patient example in the 2023 reporting year: a patient born on Feb. 1st with an encounter on March 1st would be in the denominator for the QPP 130 implementation and not in the denominator for the eCQM CMS 68 implementation. How are we supposed to handle this specific difference in these two "equivalent" measures? Is the CQL incorrect in the implementation of CMS 68 or is the specification for QPP 130 incorrect? While it could be both are "correct", this assumption would require two separate implementations for seemingly equivalent measures, which is an additional burden on implementation providers (something we would prefer to avoid). 

Finally, in general, as there may be other differences in implementation between eCQM and QPP measure specifications related to age range, timing ranges and reference codes (e.g., ICD-10-CM diagnosis codes), are there general guidelines how to handle implementation of the same measure in the two different systems (eCQM and QPP) in the presence of these types of differences? That is, is the eCQM implementation or the QPP specification always the source of truth (reporting requirements aside)?