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Measure Specification

Define Key Terms, Data Elements, Codes, and Code Systems

Measure developers must precisely define terms used in the numerator or denominator statement, or in allowable denominator exclusions, numerator exclusions, and denominator exceptions. The measure developer should include enough detailed information in the denominator, numerator, denominator exclusions, numerator exclusions, and denominator exceptions so that each person collecting data for the measure will interpret specifications in the same way.

If the measure developer is allowing multiple data collection methods, they should produce detailed specifications for each method. Measure developers construct some measures by using precisely defined components or discrete pieces of data, often called data elements. Technical specifications include the “how” and “where” to collect the required data elements. The measure developer should fully specify measures, including all applicable definitions and codes. For more information see the Specify the Code section. Precise specifications are essential for successful implementation.


  • Up-to-date vaccination status requires a clear definition of which type of vaccinations need assessment along with the definition of “up-to-date.”

Patient medical record data from electronic health records (EHRs) and other clinical systems (for example, electronic clinical quality measures [eCQMs]) or measures specified for use in an EHR and other electronic clinical systems) consist of patient-level information coded in such a way for extraction in a format for measure calculation. Information entered in an EHR and other electronic clinical systems, but not coded in a structured field, may require special processing by measure implementers.

Patient medical record data from paper charts, EHRs, and other electronic clinical systems (if not specified for an EHR) require instructions for abstraction. It is important to specify which value when there will be multiple values in a record, e.g., average of all lab values in a year, only the most recent lab value, or the first lab value during a hospitalization. The level of detail may require specifying allowable terms, allowable places in the record, and the allowable values. The measure developer should assess inter-rater reliability to ensure the specifications are clear and unambiguous, see Reliability.


  • Allowable terms used from the record: hypertension; HTN; high blood pressure; ↑BP
  • Allowable places within the record: problem list, history and physical, and progress notes
  • Allowable values: systolic blood pressure <130, urine dipstick result +1 or greater.

Claims data require information regarding type of claim, data fields, code types, and lists of codes.


  • The Acute Myocardial Infarction (AMI) mortality measure includes admissions for Medicare fee for service beneficiaries aged ≥65 years discharged from non-federal acute care hospitals having a principal discharge diagnosis of AMI and with a complete claims history for the 12 months prior to the date of admission. The codes International Classification of Diseases - 10th Revision- Clinical Modification code I21.xx, excluding those with I22.xx (AMI, subsequent episode of care).
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