Quality Measure Implementation Guide (STU5)
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Quality Measure Implementation Guide (STU5), published by HL7 International / Clinical Quality Information. This guide is not an authorized publication; it is the continuous build for version 5.0.0-draft built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7/cqf-measures/ and changes regularly. See the Directory of published versions



See the eCQI Resource Center for additional definitions

Clinical Quality Framework (CQF)

The Clinical Quality Framework is a joint effort by the Clinical Decision Support and Clinical Quality Information Work Groups to identify, develop, and harmonize standards that promote integration and reuse between Clinical Decision Support (CDS) and Clinical Quality Measurement (CQM). Source


A measure score in which a population is identified from the population of all items being counted. For example, one can identify all the patients who have had H1N1 symptoms. This population is very similar to the Initial Population but is called a Cohort Population for public health purposes.

Continuous Variable

A measure score in which each individual value for the measure can fall anywhere along a continuous scale and can be aggregated using a variety of methods such as the calculation of a mean or median (for example, mean number of minutes between presentation of chest pain to the time of administration of thrombolytics). Source


Denominator criteria define the patients, subjects, or events that should be included in the lower portion of a fraction used to calculate a rate, proportion, or ratio. The denominator can be the same as the initial population, or a subset of the initial population to further constrain the population for the purpose of the measure.

For measures that include multiple populations, different populations may have different denominators, grouping the denominators along specific criteria (e.g. patient’s age, diagnosis, surgical procedures, prior myocardial infarction, etc.).

Different measures within a measure set (see A.18, Quality Measure Set) may have different Denominators (e.g., measure #1 Denominator = Initial Population AND Smoker; measure #2 Denominator = Initial Population AND Atrial Fibrillation). A Denominator can have inclusion and exclusion criteria.

Denominator Exception

Denominator exceptions are conditions that should remove a patient, subject, or event from the denominator of a measure only if the numerator criteria are not met. Denominator exception allows for adjustment of the calculated score for those providers with higher risk populations. Denominator exception criteria are only used in proportion measures.

Denominator Exclusion

Denominator exclusion criteria define patients, subjects, or events that should be excluded from the denominator. Denominator exclusions are used in proportion and ratio measures to help narrow the denominator. For example, patients with bilateral lower extremity amputations would be listed as a denominator exclusion for a measure requiring foot exams.

Direct Reference Code

A direct reference code (DRC) is a specific code that is referenced directly in the QM logic to describe a data element or one of its attributes. Direct reference code metadata include the description of the code, the code system from which the code is derived, and the version of that code system.

Digital Quality Measure (dQM)

A clinical quality measure that is expressed and formatted to use data from electronic health records (EHR) and/or health information technology systems to measure healthcare quality, specifically data captured in structured form during the process of patient care. Synonymous with eCQM

Electronic Clinical Quality Measure (eCQM)

A clinical quality measure that is expressed and formatted to use data from electronic health records (EHR) and/or health information technology systems to measure healthcare quality, specifically data captured in structured form during the process of patient care. So they can be reported from an EHR, the FHIR Measure Resource is used to format the eCQM content using QI Core to define the data elements and Clinical Quality Language (CQL) to express the logic needed to evaluate a provider or organization’s performance. Source

Health Quality Measures Format (HQMF)

An HL7 Version 3 normative standard for the representation of quality measures. This specification provided the base requirements for the FHIR Measure resource.

Initial Population

The initial population criteria refers to all patients, subjects, or events to be evaluated by a quality measure involving patients or subjects who share a common set of specified characteristics. All patients, subjects, or events counted (for example, as numerator, as denominator) are drawn from the initial population.

Measure Population

Continuous variable measures do not have a Denominator, but instead define a Measure Population. To be in the Measure Population, a patient must be in the Initial Population. Proportion and Ratio measures do not have a Measure Population, but instead define a Denominator.

Measure Population Exclusion

Measure Population Exclusions are used in Continuous Variable Measures to define instances that should not be included in the Measure Population.


Numerator criteria define the patients, subjects, or events that should be included in the upper portion of a fraction used to calculate a rate, proportion, or ratio. Also called the measure focus, it is the target process, condition, event, or outcome.

Numerator criteria are the processes or outcomes expected for each patient, subject, or event defined in the denominator (for rate and proportion measures) or initial population (for ratio measures). A numerator statement describes the clinical action that satisfies the conditions of the measure.

Numerator Exclusion

Numerator exclusion criteria define patients, subjects, or events to be excluded from the numerator. Numerator exclusions are used in proportion and ratio measures to help narrow the numerator (for inverted measures).

Outcome Measure

A measure that assesses the results of healthcare that are experienced by patients: clinical events, recovery and health status, experiences in the health system, and efficiency/cost. Source

Process Measure

A measure that focuses on a sequence of actions or steps that should be followed to provide high quality evidence-based care. There should be a scientific basis for believing that the process, when executed well, will increase the probability of achieving a desired outcome. Source


A score derived by dividing the number of cases that meet a criterion for quality (the numerator) by the number of eligible cases within a given time frame (the denominator) where the numerator cases are a subset of the denominator cases (for example, percentage of eligible women with a mammogram performed in the last year). Source

Quality Measure Set

A unique grouping of measures carefully selected to provide, when viewed together, a robust picture of the care provided in a given domain (e.g., cardiovascular care, pregnancy).

Quality Measure (or Performance Measure)

A numeric quantification of healthcare quality for a designated accountable healthcare entity, such as hospital, health plan, nursing home, clinician, etc. A healthcare performance measure is a way to calculate whether and how often the healthcare system does what it should. Measures are based on scientific evidence about processes, outcomes, perceptions, or systems that relate to high-quality care. Source

Rate Aggregation

An organization or clinician uses rate aggregation to determine measure rate and based upon the entities’ aggregate data and summarizes the performance of the entity over a given time period (e.g., monthly, quarterly, yearly). The aggregated data are derived from the results of a specific measure algorithm and, if appropriate, the application of specific risk adjustment models.


A ratio is a score that is derived by dividing a count of one type of data by a count of another type of data. For example, the number of patients with central lines who develop infection divided by the number of central line days. Source


Criteria used to classify populations into one or more characteristics, variables, or other categories. These subsets of the overall population, or stratifications, are a form of risk adjustment, and are used in analysis and interpretation. Examples of stratification include age, discharge status for an inpatient stay, facility location within a hospital (e.g., ICU, Emergency Department), surgical procedures, and specific conditions.

Supplemental Data Elements

Additional variables required for risk adjustment or other purposes of data aggregation. Comparison of results across strata can be used to show where disparities exist or where there is a need to expose differences in results. Examples of supplemental data elements include payer, ethnicity, race and gender.


Acronym   Definition
API Application Program Interface
CDS Clinical Decision Support
CMS Centers for Medicare and Medicaid Services
CQFM Clinical Quality Framework Measures
CQL Clinical Quality Language
CQM Clinical Quality Measures
dQM Digital Quality Measure
eCQM electronic Clinical Quality Measures
DEQM Data Exchange for Quality Measures
EHR Electronic Health Record
ELM Expression Logical Model
FHIR Fast Healthcare Interoperability Resources
HEDIS Healthcare Effectiveness Data and Information Set
HL7 Health Level Seven
HQMF Health Quality Measure Format
ICU Intensive Care Unit
IG Implementation Guide
JSON JavaScript Object Notation
LOINC Logical Observation Identifiers Names and Codes
QDM Quality Data Model
QI Core Quality Improvement Core
QRDA Quality Reporting Document Architecture
R4 FHIR Release 4
REST Representational State Transfer
SNOMED-CT Systematized Nomenclature of Medicine – Clinical Terms
STU FHIR Release (STU)
URI Uniform Resource Identifier
URL Uniform Resource Locater
XML eXtensible Markup Language