What is Clinical Quality Language (CQL)?

Clinical Quality Language (CQL) is an HL7 standard for trial use (STU). It is part of the effort to harmonize standards between electronic clinical quality measures (eCQMs) and clinical decision support (CDS). CQL provides the ability to express logic that is human readable yet structured enough for processing a query electronically. In the future, CQL is being considered for use in all of the clinical quality measure HQMF electronic specifications. It will replace the logic expressions currently defined in the Quality Data Model (QDM) and QDM (beginning with v5.0) will include only the conceptual model for defining the data elements (the data model).

What are the benefits of using Clinical Quality Language?

CQL is more modular, flexible and robust expression of the logic. It allows logic to be shared between measures and with decision support. Learn more about the advantages of CQL from this presentation: Benefits of CQL [May 2017]

How is Clinical Quality Language used by measure authors and implementers?

CQL is a high-level authoring language that’s intended to be human readable. It allows measure authors to express data criteria and represent it in a way that is suitable for language processing. CQL doesn't specify what format the input data must be in, but a CQL implementation will interact with the data using the form of the data model identified in the CQL. 

Measure authors with access to the Measure Authoring Tool (MAT) CQL Staging Environment are able to use the tool to test creating measures using CQL. Visit the MAT webpage for more information.  

Learn about the use of CQL and Expression Logical Model in an eCQM calculation environment: Electronic Clinical Quality Measure (eCQM) Calculation Architecture [April 2017]

CQL Formatting and Usage Wiki

This wiki serves as a collaborative workspace for the development of CQL formatting conventions and usage patterns for the representation of logic within quality measures.  All users have edit rights to be able to submit edits, add comments and concerns. Items on the Wiki are a work in progress and subject to change.

Visit the CQL Formatting and Usage Wiki for more guidance. 

CQL Online

CQL Online is a tool developed by ESAC, Inc. to provide a "sandbox" where eCQM developers and implementers, who do not have access to the Measure Authoring Tool CQL Staging environment, can "play" around with CQL. The tool allows users to get a feel for what CQL looks like and how to write proper expressions in this new and powerful language.

More specifically, CQL Online is a syntax directed editor for writing expressions in CQL. It is open source and intended for educational purposes.

CQL Testing

The Centers for Medicare and Medicaid Services (CMS) is considering using CQL to represent eCQM logic. CMS invites electronic health record (EHR) vendors and other implementers to participate in testing the new CQL standard for eCQMs by providing feedback related to implementation and evaluation of measures using CQL-based standards. Participation includes reviewing and/or implementing CQL-based measures and associated artifacts, and providing feedback on the utility. CMS invites participation by EHR vendors and implementers who can commit to testing support for the remainder of the testing phases (ending in Fall 2017).

Interested parties should send an email expressing interest (including vendor organization, name, and contact information for two staff) to cql-esac@esacinc.com.

What is the timeline for the transition to Clinical Quality Language?

Testing is currently underway for CQL. Contingent upon successful testing, CQL measure development is anticipated to begin Fall 2017 with CQL-based measure publication anticipated in Spring 2018.

Where can I find more information?

CQL Questions and Answers:

The CQL Q&As page contains common questions and answers on CQL (also accessible by selecting the Clinical Quality Language (CQL) Q&As link on the right navigation bar).

CQL Events:

To search for upcoming CQL events, go to the eCQI Events calendar.

Past CQL Presentations (also accessible by selecting the CQL Educational Resources link on the right navigation bar).

What tools are available for using Clinical Quality Language?

More information about CQL is found at:

CQL is discussed in the HL7 CQF-on-FHIR forum and CQL STU comments are discussed during the HL7 Clinical Decision Support Work Group calls. Find information about upcoming calls here.

QDM References:

The Quality Data Model v5.3 For Use By Measure Developers Creating Measures Using Clinical Quality Language (CQL) [June 2017]

The Final Draft Quality Data Model v5.02 [November 2016]

(QDM v5.02 is available in the MAT CQL staging release and CQL Online)

The Proposed Draft Quality Data Model v5.01[October 2016]

The Draft Quality Data Model v5.0 with Errata specifications[September 2016]

How can I submit feedback?

For issues, comments, and questions related to CQL, please use the CQL JIRA Issue Tracker.  

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