The CMS529v4 and CMS844v4 logic guidance for the Initial Population states: "All Medicare Fee-For-Service and Medicare Advantage encounters meeting the above criteria should be included [...]". But the measure logic does not take into account whether the payer was active during the encounter. The existence of a medicare payer at any time for the patient allows the encounter to be included in the IPP.

Inpatient Encounters
["Encounter, Performed": "Encounter Inpatient"] InpatientEncounter
  with ( ["Patient Characteristic Payer": "Medicare FFS payer"]
    union ["Patient Characteristic Payer": "Medicare Advantage payer"] ) Payer
    such that Global."HospitalizationWithObservationLengthofStay" ( InpatientEncounter ) < 365
      and InpatientEncounter.relevantPeriod ends during day of "Measurement Period"
      and AgeInYearsAt(date from start of InpatientEncounter.relevantPeriod)>= 65

The measure logic retrieves Patient Characteristic Payer for Medicare FFS payer & Medicare Advantage payer and assigns them variable named "Payer". But it does not use this variable. It appears as if the intention was to check if the InpatientEncounter.relevantPeriod occurrs during the Payer period. But that does not happen.

The effect is that if a patient ever had Medicare FFS payer or Medicare Advantage payer, regardless of whether it was active during the time of the encounter, then that encounter will be considered for inclusion in the Initial Population.

Our questions: Should these measures consider Payer effectiveTime when evaluating the encounter's inclusion to the IPP? If so, do we achieve that by altering the measure logic?