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A Mann-Whitney U test is used to compare the differences between two independent samples when the sample distributions are not normally distributed and the sample sizes are small (n <30). Zach. (2018, December 22). Mann-Whitney U Test. Statology. Retrieved November 16, 2023, from

Material Change

A material change is one that changes the specifications of a quality measure to affect the original measure’s concept or logic, the intended meaning of the measure, or the strength of the measure relative to the measure evaluation criteria.

McDonald's Omega

McDonald's omega (ω) is a quantitative test of internal consistency reliability based on a one-factor model. McDonald's omega is a reliability coefficient similar to Cronbach's Alpha. Omega has the advantage of taking into account the strength of association between items and constructs and item-specific measurement errors. ResearchGate. (2015). Re: What are the commonly used cut-off values for McDonald's Omega? Retrieved December 18, 2023 from:

McNemar's Test

The McNemar test is a non-parametric test used to analyze paired nominal data. The minimal sample size required for the McNemar test is at least ten discordant pairs.  Sundjaja, J.H., Shrestha, R., & Krishan, K. (2021). McNemar and Mann-Whitney U Tests. StatPearls Publishing.

Measure Maintenance

Measure maintenance is the periodic and consistent reviewing, evaluating, and updating of performance measures to ensure continued reliability, validity, feasibility, importance, usability, and currency with science. It also involves comparison to similar measures for potential harmonization.

Measure Score

The measure score is the numeric result computed by applying the measure specifications and scoring algorithm. The computed measure score represents an aggregation of all appropriate patient-level data (e.g., proportion of patients who died, average lab value attained) for the measured entity (e.g., hospital, health plan, home health agency, clinician). The measure specifications designate the measured entity and to whom the measure applies.

Measure Set

A measure set is a group of measures related in some way such as measures addressing a specific condition, procedure, or specialty.

Measure Steward

A measure steward is an individual or organization that owns a measure and is responsible for maintaining the measure. Measure stewards are often the same as measure developers, but not always. Measure stewards are also the ongoing point of contact for people interested in a given measure.

Measure Testing

Measure testing is the empirical analysis to demonstrate the reliability and validity of the measure as specified, including analysis of issues posing threats to the validity of conclusions about quality of care such as exclusions, risk adjustment/stratification for outcome and resource use measures, methods to identify differences in performance, and comparability of data sources/methods.

Measure Validity (part of Scientific Acceptability)

Measure validity is when the measure accurately represents the evaluated concept and achieves the intended purpose (i.e., to measure quality). For example, the measure

  • clearly identifies the evaluated concept (i.e., face validity)
  • includes all necessary data elements, codes, and tables to detect a positive occurrence when one exists (i.e., construct validity)
  • includes all necessary data sources to detect a positive occurrence when one exists (i.e., construct validity)

Measured Entities

Measured entities are the front-line clinicians and their organizations, including health information technology, collecting quality measurement data. Measured entities are the implementers of quality measures. The effect of quality measure data collection on clinician workflow can be negative. There may be effects on their payments, positive and negative, with respect to reporting and actual performance on quality measures. Because of these potential effects, measured entities should be involved in all aspects of the Measure Lifecycle.

Measures Under Consideration (MUC)

The Measures Under Consideration is a list of quality and efficiency measures HHS is considering adopting, through the federal rulemaking process, for use in the Medicare program. Made publicly available by December 1 each year for categories of measures that are described in section 1890(b)(7)(B)(i)(I) of the Social Security Act as amended by Section 3014 of the Patient Protection and Affordable Care Act (ACA).

Medical Record (Data Source)

The medical record is data obtained from the records or documentation maintained on a patient in any health care setting (e.g., hospital, home care, long term care, practitioner office). Includes electronic and paper medical record systems.


Metadata are data that describe data.

Minor Change

A minor change does not change the process of data collection, aggregation, or calculation, nor does it change the intended meaning of the measure or the strength of the measure in terms of the measure evaluation criteria. For example, the code system updates to eCQMs with the Annual Update are minor changes.


Morbidity is the rate of incidence of disease. For example, if a lumbar puncture is improperly performed, significant morbidity may follow. It also can refer to the relative incidence of a particular disease state or symptom.


Mortality is the number of deaths in a given time or place, the proportion of deaths to population. “Death rate” is also called “mortality rate.”

Multiple Chronic Conditions (MCC)

Multiple chronic conditions (MCC) is the situation in which an individual has two or more concurrent chronic conditions that collectively have an adverse effect on health status, function, or quality of life, which require complex health care management, decision-making, or coordination.