​Thank you for your question related to timing phrases. The CQL expression 'ends 1 hour or less on or before start of' is used to identify the end of an emergency department visit 1 hour or less prior to or on the start of an inpatient encounter. In the CQL expression, the 'one hour or less on or before' is evaluated using an interval calculation for a time comparison, which is calculated to 60 minutes or less, per the measure intent. In CQL, duration is a different timing operation and represents a change from the previous QDM logic in which an 'hour' may have included a duration of 1 hour and 59 minutes. For more information on this topic, please see the Cooking with CQL examples 06-27-2019 located here: https://github.com/esacinc/CQL-Formatting-and-Usage-Wiki/wiki/Cooking-with-CQL-Examples ​

Ambiguity within the date/time calculations within the eCQMs could lead to inaccurate results. In the absence of clear guidance and specification, different vendors may interpret these differently leading to mismatched results between vendor systems and also the results calculated by CMS and TJC.