CQL is a Health Level Seven International® (HL7®) authoring language standard that is intended to be human readable. It is part of the effort to harmonize standards used for 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. CQL is the expression logic used in Health Quality Measure Format (HQMF) beginning with the eCQMs implemented in calendar year 2019. CQL replaces the logic expressions previously defined in the Quality Data Model (QDM). Beginning with v5.3, QDM includes only the conceptual model for defining the data elements (the data model). Measure authors with access to the Measure Authoring Tool (MAT) can use the tool to author measures using CQL. Visit the MAT webpage for more information.
CQL allows for a more modular, flexible, and robust expression of the logic. It allows logic to be shared between measures and with clinical decision support.
The CQL standards are located on the HL7 Website: CQL Specification. The latest version of CQL is v1.5.2: Current Official Published Version - Normative Release 1 (mixed Normative/Trial-use content + 1 technical errata), based on Fast Healthcare Interoperability Resources® R4.
Find the QDM versions for use with Clinical Quality Language (CQL) on the QDM page.
Explore these resources to get an overview of CQL and learn how to implement CQL from experts.
Access these tools to support your use of CQL.
View these resources to learn about CQL formatting, usage, and standards.
Teach Me CQL Video Series
Normalize Interval (YouTube) - Video Short - July 2022
Time Zone Considerations (YouTube) - Video Short - July 2022
Latest, LatestOf, Earliest, EarliestOf, HasStart, HasEnd (YouTube) - Video Short - August 2022
Coalesce (YouTube) - Video Short - August 2022
Get a start with CQL by visiting the CQL FAQs page to review common questions and answers.
Visit the CQL Formatting and Usage Wiki. The Wiki serves as a collaborative workspace for the development of CQL formatting conventions and usage patterns for the representation of logic within electronic clinical quality measures (eCQMs). All users have edit rights to submit edits, and add comments and concerns. Items on the Wiki are a work in progress and subject to change.
Join the CQL Technical Chat Discussion. (Log in or sign up for a free account.)
Participate in an upcoming Health Level Seven International® (HL7®) Clinical Decision Support (CDS) Work Group call. This Work Group discusses CQL in the HL7 Clinical Quality Framework-on-Fast Healthcare Interoperability Resources® (CQF-on-FHIR).
Add to or review the CQL Mixed Normative / Trial Use Specification comments on the HL7 website (search for CQL to view the comment page for the most current version of the standard).
Submit general information questions about CQL to ecqm@icf.com.
Submit feedback on CQL issues, comments, and technical questions to the ONC Jira CQL Issue Tracker.