We are developing developing CQL-HQMF and testing cases in Bonnie. We noticed that occurrence is an issue for all measure. we have 2 questions regarding this issue.
1. most of current eCQM use "intersect" in Denominator section to sum up IPP along with all definitions in DENOM. For example:
define”Denominator”
"Initial Population" intersect
"Encounter with Discharge Disposition"

Q1 - Is this intersect to ensure all IPP conditions carried down to DENOM section including all occurrences defined in IPP? Should this pattern be used in other population sections?

2. According to v3_IG_CQL_HQMF, we agree that a specific occurrences is defined in Definition block (data-type level) and then carried to the following definitions or next population sections by calling same definition name. It is very straight forward for simple measure such as CAC3. For a complex measure, more than one data types needs occurrencing (Encounter, Performed and Diagnostic Study, Performed in VTE-3) AND sometimes in combination of AND/OR conditions. In a complex situation, calling definition name is very meticulous task. QDM-eCQMs uses "Occurrence A of" to identify a specific occurrence. It provides convenience for CQL conversion for this round. In the future, modifying CQL-eCQMs is much difficult by search definition names among 30 or 40 definition blocks.

Q2 - If "intersect to ensure all IPP conditions carried down to DENOM section including all occurrences defined in IPP", could we use same concept for Other sections so we do not need to call individual definition name. For example:
define "Denominator Exclusions":
“Denominator” intersect
("Inpatient Encounter" Encounter
where Encounter.facilityLocation in "Neonatal Intensive Care Unit (NICU)"
or Encounter.dischargeDisposition in "Patient Expired"
or Encounter.dischargeDisposition in "Discharge To Acute Care Facility")

We tested in Bonnie and the results tell us it does not work in this way. We tired to find an alternative way for occurrence implementation .

Q3 - What is the purpose to use "IPP Intersect ..." in DENOM when to use calling definition name for occurrences? It seems it is unnecessary.

Sorry for the lengthy questions Please advise,

Yanyan