Greetings,

Is Following response in CQLIT-41 for EHR software developers who wants to absorb CQL logic in their software?

Ref link-https://oncprojectracking.healthit.gov/support/browse/CQLIT-41

Part of question-

Why develop measure logic in a language with no support rather than develop the measures in Java, C# or any other commercially supported programming language? 

 oncprojectracking Response-

There are open source tools available to evaluate ELM for both the JavaScript and Java platforms. There is also a .NET toolkit for ELM that can support translation and evaluation.

Developing the measures in Java, C#, or any other commercially supported language would not achieve the goal of sharing the measure logic in a platform independent way, nor would it serve as a vehicle for communicating the intent of the measures in the way that CQL/ELM does. Traditional programming languages do not support the required set of operations for expressing measure logic, and traditional query languages, though closer to the mark, still do not support important aspects like terminology and interval-based timing.

The approach taken by CQL/ELM is basically what you are describing here, in that we have isolated the core expression of the operations involved, and built an execution model that enables implementers to evaluate CQL measures by just implemented a few well-defined interfaces, as described by the Java-based ELM evaluation engine. Effectively, to implement CQL evaluation, you only have to implement the data access layer which consists of indexed access with a simple conjunctive filter on well-known attributes.

For example, the FhirDataProvider here:

https://github.com/DBCG/cql_engine/blob/master/cql-engine-fhir/src/main/java/org/opencds/cqf/cql/data/fhir/FhirDataProviderStu3.java

 implements data access for a FHIR endpoint, enabling CQL evaluation against any FHIR source.