Dictionary

M

Markov ModelConceptMarkov State Model, Multi-State Markov Framework

A Markov model is a memoryless state-transition model used in economic evaluation: people move between health states each cycle, accruing costs and QALYs.

Martingale ResidualConceptCounting-Process Residual, Survival Model Residual

A residual used to diagnose the fit of a Cox model, checking the functional form of continuous covariates and identifying influential observations.

Mass ScreeningTermPopulation-Wide Screening, Universal Screening

A screening programme offered to an entire defined population regardless of individual risk factors, unlike targeted screening of higher-risk subgroups.

Master ProtocolTermMaster Trial Protocol, Overarching Trial Framework

An overarching trial framework establishing shared infrastructure to efficiently evaluate multiple treatments, diseases, or both within a single coordinated structure.

Matching DesignTermMatched Study Design, Matched-Pairs Design

A study design pairing treated individuals with similar untreated individuals on shared characteristics, to reduce confounding when estimating causal effect.

Matching MethodTermMatching Technique, Value Matching

A health state valuation technique in which respondents adjust one attribute of an outcome until two alternatives seem equally preferable.

Matching-Adjusted Indirect ComparisonConceptMAIC, Weighted Indirect Comparison

A method comparing treatments from separate trials with different populations by reweighting one trial's patient data to match the other trial's reported characteristics.

Maternal Health EconomicsTermMaternal Care Economics, Obstetric Health Economics

The application of health economic evaluation to healthcare services during pregnancy, childbirth, and the postpartum period.

Matrix AlgebraConceptLinear Algebra, Matrix Mathematics

Matrix algebra provides a compact way to represent and manipulate related quantities arranged in rows and columns.

Matrix InversionConceptMatrix Inverse, Inverse Matrix Computation

Matrix inversion finds a matrix that reverses the effect of a square matrix.

Matrix MultiplicationConceptMatrix Product, Matrix Dot Product

Matrix multiplication combines two organised sets of quantities so that the rows of the first matrix are matched with the columns of the second.

Mature MinorTermGillick Competence, Adolescent Consent Capacity

A legal doctrine letting a sufficiently mature adolescent below the age of majority consent to certain treatments independently of parental involvement.

Maximin CriterionTermRawlsian Criterion, Maximin Rule

A social welfare decision rule judging an allocation by the wellbeing of the worst-off group, seeking to maximise that minimum level.

Maximum Likelihood EstimationConceptMLE, Likelihood Maximisation

A method estimating a model's parameters by finding the values that make the observed data most probable.

Maximum Tolerated DoseTermMTD, Highest Tolerated Dosage

The highest drug dose that can be given without unacceptable toxicity, typically found during early-phase trials through dose escalation.

MCDA in HTAConceptMulti-Criteria HTA, MCDA Appraisal

MCDA in HTA uses multi-criteria decision analysis to appraise health technologies on explicit, often weighted, criteria such as health gain and severity.

Me-Too DrugTermCopycat Drug, Follow-On Compound

A newly developed drug chemically similar to and working through the same mechanism as an existing treatment, offering limited additional benefit.

MeanConceptArithmetic Average, Statistical Average

A measure of central tendency obtained, in its arithmetic form, by dividing the sum of values by their count; a population mean is the corresponding expected value.

Mean Absolute ErrorConceptMAE, Absolute Error Metric

The arithmetic average of the absolute differences between numerical predictions and their corresponding observed values, expressed in the outcome’s units.

Mean Squared ErrorConceptMSE, Squared Error Metric

Mean squared error is the average of squared differences between predictions or estimates and their corresponding observed or reference values, evaluated over a specified set or sampling process.

Means TestingTermMeans Test, Income Screening

A method of determining eligibility for a benefit based on direct assessment of an individual's or household's income or assets.

Measles EconomicsTermMeasles Cost of Illness, Rubeola Economics

The application of health economic evaluation to measles, a highly contagious viral disease largely preventable through vaccination.

Measurement ErrorConceptObservational Error, Measurement Inaccuracy

Measurement error is the discrepancy between an observed or recorded value and the intended value of the quantity being measured, arising from the measurement process rather than sampling alone.

Measurement Error MethodsTermError-Correction Methods, Measurement-Error Adjustment

Statistical techniques correcting for bias arising when a model variable is measured with error rather than reflecting its true value exactly.

Measurement PropertyTermPsychometric Property, Instrument Property

A characteristic that describes how well a health measurement instrument performs, such as its validity, reliability or responsiveness, used to judge whether the instrument captures the intended concept accurately and consistently.

Mechanism DesignConceptIncentive Design, Reverse Game Theory

Mechanism design uses game theory to set rules, such as auctions, tenders or matching schemes, under which self-interested choices serve a chosen goal.

MedianTermMiddle Value, 50th Percentile

A central tendency measure representing the middle value of an ordered dataset, dividing it into two equal halves.

Mediation AnalysisConceptMediator Modelling, Indirect-Effect Analysis

A statistical approach examining whether an exposure's effect on an outcome operates through an intermediate variable, called a mediator, rather than directly.

Medical FutilityTermClinical Futility, Treatment Futility

A judgement that a proposed treatment is unlikely to produce meaningful clinical benefit, raising ethical questions about whether it should continue.

Medical ImagingTermDiagnostic Imaging, Clinical Imaging

The use of techniques such as X-ray, ultrasound, CT and MRI to produce images of the body for diagnosis, monitoring and treatment planning.

Medical Loss RatioConceptMLR, Insurer Loss Ratio

A regulatory measure requiring insurers to spend a minimum percentage of premium revenue on claims and quality improvement, rather than administration or profit.

Medical NecessityTermClinical Necessity, Necessity Standard

A determination that a service or treatment is required to diagnose or treat a condition, consistent with accepted clinical standards.

Medical Necessity DeterminationTermNecessity Adjudication, Coverage Necessity Check

A formal insurer assessment of whether a proposed service meets a plan's clinical coverage criteria, typically required before authorisation.

Medical Products BlockTermMedical Products Pillar, Medicines and Technologies Block

A core health system building block encompassing access to essential medicines, vaccines, and technologies of assured quality, safety, and efficacy.

Medical UnderwritingTermHealth Underwriting, Risk Underwriting

A practice where an insurer assesses an applicant's health status to determine coverage and pricing, historically used before regulatory reforms restricted it.

Medication AdherenceConceptDrug Adherence, Regimen Compliance

The extent to which a patient takes a prescribed medication as recommended, covering consistent daily use and appropriate long-term continuation.

Medication Carve-OutTermPharmacy Carve-Out, Drug Benefit Carve-Out

An insurance design arrangement in which prescription drug coverage is managed separately from general medical benefits, typically by a pharmacy benefit manager.

Medication ErrorTermDrug Error, Prescribing Error

A preventable mistake occurring anywhere in the medication use process, from prescribing through dispensing to administration, whether or not harm results.

Medication Error RateTermDrug Error Rate, Error Frequency

A measure of how frequently mistakes occur in prescribing, dispensing, or administering medications within a healthcare organisation.

Medication Management SystemTermMMS, Pharmacy Management Platform

A digital tool supporting safe medication use, covering prescribing decision support, dispensing verification, and adherence monitoring functions.

Medication PersistenceTermDrug Persistence, Therapy Continuation

The duration a patient continues taking a prescribed medication from initiation until discontinuation, distinct from adherence's measure of consistency while in use.

Medication Possession RatioConceptMPR, Possession Ratio

The medication possession ratio (MPR) is the total days' supply dispensed divided by the days in the period. Unlike PDC, it can exceed 1 unless capped.

Medication ReconciliationTermMed Rec, Drug Reconciliation

The process of creating an accurate medication list, comparing it against new orders at care transitions, and resolving discrepancies to prevent errors.

Medication SafetyTermSafe Medication Use, Drug-Safety Practice

Freedom from preventable harm associated with medication use, covering safe practice throughout prescribing, dispensing, administration, and monitoring.

Medication Therapy ManagementTermMTM, Pharmacist-Led Therapy Review

A pharmacist-provided structured service reviewing a patient's complete medication regimen to identify and address problems such as interactions or non-adherence.

Medicinal ProductTermMedicine, Pharmaceutical Product, Drug Product

In health economics, a manufactured product containing one or more active substances used to treat, prevent, or diagnose disease, and the unit whose price, value, and reimbursement pharmacoeconomic evaluation assesses.

Memory CareTermDementia Care Unit, Cognitive Care

Specialised residential long-term care designed for people with dementia or memory-related conditions, featuring a secure environment and dementia-trained staff.

MemorylessnessConceptMemoryless Property, No-Memory Property

The defining property of a Markov process that future transition probabilities depend only on the present state, with no influence from the path taken.

Meningitis EconomicsTermMeningococcal Economics, Meningitis Cost of Illness

The application of health economic evaluation to meningitis, an infection of the brain and spinal cord membranes caused by various bacterial and viral pathogens.

Mental Accounting ConceptTermMental Accounting, Psychological Accounting

The tendency to categorise and treat money differently depending on its source or intended use, rather than as fully interchangeable.