Dictionary
The Dictionary provides concise definitions of health economics terms, arranged alphabetically for quick reference. Use it to understand unfamiliar terminology or confirm the meaning of a specific term.
A
- Absorbing StateAbsorbing Health State, Absorbing Markov State
- A health state within a Markov model from which no further transitions are possible, most commonly death, once entered permanently.
B
- Bubble DiagramInfluence Sketch, Model Sketch
- A simplified visual sketch of a decision-analytic model's structure, using labelled circles and arrows to depict health states before the full build.
C
- Cardinal ScalingCardinal Measurement, Interval-Level Scaling
- A measurement approach in which the size of numerical differences between health states reflects the actual magnitude of preference differences between them.
- Category RatingCategory Scaling, Categorical Rating Scale
- A health state valuation method in which respondents assign states to a fixed number of ordered categories, or rate them on a numerical scale.
- Choice-Based MethodChoice-Based Valuation, Preference Elicitation Choice
- A health state valuation technique in which respondents choose between alternative states or gambles, such as the standard gamble or time trade-off.
- Cohort ModelCohort-Level Model, Markov Cohort Approach
- A cohort model follows the expected movement of a defined group through mutually exclusive health states over time.
- Cohort SimulationCohort-Level Simulation, Markov Cohort Run
- The process of running a Markov model by tracking the proportion of a hypothetical cohort in each health state over cycles, not individual patients.
- Cohort TraceMarkov Trace, State-Occupancy Trace
- A cohort trace is the cycle-by-cycle record of a state-transition model’s expected cohort distribution across its health states under a specified strategy.
- Constant Sum AllocationFixed-Total Allocation, Points Distribution Method
- A health state valuation method in which respondents distribute a fixed total, often one hundred points, across health states by relative desirability.
- CrosswalkScore Mapping, Instrument Mapping
- A statistical mapping converting health state scores from one version of an instrument to an equivalent score on another version.
D
- Direct ElicitationDirect Valuation, First-Hand State Valuation, Direct Utility Assessment
- A health state valuation approach in which respondents value a state directly, using techniques such as the standard gamble or time trade-off.
- DisutilityUtility Loss, Negative Utility
- The reduction in utility from experiencing a health state worse than full health, expressed as a value below one on the utility scale.
E
- Experienced UtilityHedonic Utility, Lived Utility
- The actual hedonic experience, such as pleasure or suffering, undergone while in a health state, unlike the decision utility anticipated in advance.
H
- Hale CalculationHALE Computation, Health-Adjusted Life Expectancy Calculation
- The process of computing health-adjusted life expectancy, combining mortality data with health state prevalence and severity weights into one summary measure.
- Health ExpectancyExpected Healthy Years, Healthy-Years Measure
- A general term for measures combining mortality and morbidity data to estimate expected years lived in a specified health state, such as disability-free.
- Health StateDescribed State Profile, EQ-5D State
- A specific combination of levels across the dimensions measured by a health status instrument, describing a person's condition at a point in time.
- Health State DefinitionMarkov State Specification, State Clinical Definition
- The precise clinical specification of each distinct health state within a Markov model, describing the criteria a patient must meet to occupy it.
- Health State Utility ValueHSUV, Health State Utility
- A health state utility value, or HSU value, is a preference-based numerical weight assigned to a health state for use in economic evaluation.
- Health State ValuationState Valuation, Utility Elicitation
- Health state valuation is the elicitation and modelling of preferences for defined states of health to assign scores on a scale anchored by dead and full health for use in economic evaluation and related decisions.
- Health StatusHealth State Overall, Overall Health Condition
- An individual's overall condition of physical, mental, and social wellbeing at a given point in time, commonly assessed using standardised instruments.
- Healthy Year EquivalentHYE, Lifetime Health Equivalent
- An alternative to the QALY deriving its valuations directly from a sequence of health states over a lifetime, rather than combining separate utility values.
I
- Increment-Decrement Table
- A multi-state life table method modelling transitions between health states, including both improvement and decline, over successive time periods.
- Indirect Elicitation
- A health state valuation approach in which a descriptive questionnaire's responses are converted into a utility value using a pre-existing scoring algorithm.
- Indirect Utility Assessment
- The process of obtaining a health state utility value by applying a scoring algorithm from a prior valuation study to a respondent's questionnaire answers.
- InitializationModel Initialisation, Starting-State Setup
- The process of specifying a model's starting conditions, such as how a simulated cohort is distributed across health states at the outset.
M
- Markov Cohort ModelCohort Markov Model, Aggregate Markov Model
- A Markov model tracking a hypothetical cohort collectively as proportions across health states over cycles, rather than simulating each patient separately.
- Markov MicrosimulationIndividual-Level Markov Model, First-Order Markov Simulation
- Markov microsimulation is an individual-level state-transition modeling method that simulates each person's sequence of health states over time using transition probabilities that may depend on current state, personal characteristics, time, and explicitly retained history.
- Markov ModelMarkov State Model, Multi-State Markov Framework
- A Markov model is a state-transition model in which a cohort or individuals move among mutually exclusive health states over repeated cycles, with future transitions determined by the current state under the model’s memory assumptions.
- Matching MethodMatching Technique, Value Matching
- A health state valuation technique in which respondents adjust one attribute of an outcome until two alternatives seem equally preferable.
- Model StructureModel Architecture, Structural Form
- The overall organisation of a health economic model, including its technique, the health states or events represented, and how they link together.
P
- Paired ComparisonPaired Preference, Pick-One-of-Two
- A health state valuation method in which respondents are shown two states at a time and indicate which they prefer, building up a ranking.
- Partitioned Survival ModelArea-Under-Curve Model, PartSA Model
- An oncology modelling technique estimating the proportion of a cohort in each health state using separately fitted survival curves for different endpoints, rather than modelling transitions.
- PathwayCare Route, Clinical Route
- The sequence of health states or clinical events a hypothetical patient may follow through a decision-analytic model, from entry to final outcome.
- Point Allocation MethodPoint Allocation, Constant Sum Method
- A health state valuation technique in which respondents distribute a fixed number of points across several health states to reflect relative preferences.
- Preference WeightPreference Coefficient, Valuation Weight
- A numerical value reflecting the relative desirability a population or individual assigns to a particular health state or outcome.
Q
- QALY Calculation MethodQALY Estimation, QALY Derivation
- The process of computing quality-adjusted life years by multiplying time spent in a health state by its utility value, then summing across states.
R
- Ranking MethodRank Ordering Method, Ordinal Ranking
- A health state valuation technique in which respondents order health states from most to least preferred, without indicating the size of preference differences.
- Rating MethodRating Scale Valuation, Category Rating Technique
- A health state valuation technique in which respondents assign a numerical score to a health state on a defined scale, such as a visual analogue scale.
- Remembered UtilityRecalled Utility, Retrospective Utility
- The retrospective evaluation a person gives of a past experience or health state, which can differ from the utility actually experienced at the time.
S
- Standard GambleSG, Reference Gamble
- The standard gamble is a choice-based health-state valuation method that finds the probability at which a respondent is indifferent between living in a certain health state and accepting a lottery between specified better and worse outcomes.
- State DefinitionState Characterisation, Health-State Description
- The precise specification of what constitutes a distinct health state within a Markov model, including the clinical criteria for assignment to it.
- State MembershipState Assignment, Cohort Allocation
- The specific health state a patient, or proportion of a modelled cohort, occupies at a given point within a Markov model.
- State OccupancyState Residence, Time in State
- The amount of time, typically in cycles, that a patient or cohort proportion spends within a given health state in a Markov model.
- State Transition DiagramMarkov Diagram, State Diagram
- A visual representation of a Markov model showing each health state as a labelled box and each permitted transition as an annotated arrow.
- State Transition ModelSTM, State-Transition Modelling
- A general term for a decision-analytic model, such as a Markov model, representing disease progression as movement between defined health states.
- Structural AssumptionStructural Modelling Assumption, Model-Form Assumption
- A simplifying premise embedded in a model's overall design, such as representing a disease with a fixed number of health states.
- Structural ValidityDimensional Validity, Internal Structure Validity
- The degree to which a model's overall architecture, including its health states and time horizon, appropriately represents the real-world process being studied.
T
- Three-State ModelThree-Compartment Model, 3-State Markov Model
- A simplified Markov structure with exactly three health states, commonly well, diseased, and death, used when a fuller structure is unnecessary.
- Time Trade-OffTTO, Life-Year Trade-Off
- A health state valuation method asking how many years in full health a respondent would consider equal to a longer period in an impaired state.
- Trace ValidationTrace Checking, Patient-Path Checking
- The review of a Markov model's cohort trace, the proportion of a modelled population in each health state over time, for clinical plausibility.