Topic

Health utility and preference elicitation

A health state utility value places a health state on a scale anchored at full health and dead, giving the weight behind each QALY. Values come from direct methods such as the standard gamble and time trade-off, or from instruments like the 15D scored with a value set. Mapping functions convert other measures into utilities.

Concepts in this topic

• 15DA generic, multi-attribute quality of life instrument measuring fifteen health dimensions, each scored on five levels, combined into a single utility index.
• Anchor-Based MIDAnchor-based MID is a minimal important difference estimated by linking score changes to an external anchor, such as a patient's global rating of change.
• AQoLAQoL (Assessment of Quality of Life) is a family of Australian multi-attribute utility instruments, AQoL-4D to AQoL-8D, that score health states for QALYs.
• CrosswalkA statistical mapping converting health state scores from one version of an instrument to an equivalent score on another version.
• DFLE CalculationThe process of computing disability-free life expectancy using a life table combining age-specific mortality rates with age-specific disability prevalence.
• Direct ElicitationA health state valuation approach in which respondents value a state directly, using techniques such as the standard gamble or time trade-off.
• Distribution-Based MIDA distribution-based MID is a minimal important difference estimated from score spread or instrument reliability, such as half a standard deviation.
• DisutilityDisutility is the loss of utility caused by a health state, adverse event or treatment, measured from a stated baseline and used to reduce QALYs.
• Hale CalculationThe process of computing health-adjusted life expectancy, combining mortality data with health state prevalence and severity weights into one summary measure.
• Health State Utility ValueA 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 ValuationHealth 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.
• Indirect ElicitationA 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 AssessmentThe process of obtaining a health state utility value by applying a scoring algorithm from a prior valuation study to a respondent's questionnaire answers.
• Interval ScalingA measurement scale property in which numerical differences correspond to equal differences in the underlying quantity, allowing meaningful arithmetic operations.
• Magnitude EstimationA psychophysical scaling method in which respondents assign numbers to stimuli reflecting their perceived relative magnitude compared to a reference stimulus.
• Mapping FunctionThe specific statistical relationship, typically estimated through regression, used within a mapping algorithm to convert a health status score into a predicted utility value.
• Multi-Attribute UtilityA utility value derived by combining preference weights across several distinct attributes of an outcome into a single overall measure.
• Multi-State Life TableA life-table framework that uses transitions among multiple living states and death to estimate how long a specified population or starting group is expected to spend in each state.
• Ordinal ScalingA measurement scale property in which values can be ranked but numerical differences do not necessarily reflect equal differences in the underlying quantity.
• Paired ComparisonA health state valuation method in which respondents are shown two states at a time and indicate which they prefer, building up a ranking.
• Point Allocation MethodThe point allocation method asks respondents to divide a fixed total of points, often 100, among health outcomes or criteria to show their relative value.
• Preference WeightA numerical value reflecting the relative desirability a population or individual assigns to a particular health state or outcome.
• ResponsivenessThe ability of an outcome measurement instrument to detect change over time in the construct it is intended to measure, in a specified population and context of use.
• Single Attribute UtilityA utility value derived from a single dimension of health or outcome, unlike multi-attribute utility, which integrates several dimensions.
• Standard GambleThe 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.
• Standardised Response MeanA responsiveness statistic calculated as the mean score change over time divided by the standard deviation of that change, unlike an effect size.
• Sullivan MethodA technique for calculating health expectancy measures by combining age-specific mortality rates from a life table with age-specific prevalence rates of disability.
• TariffThe specific set of utility weights, derived from a population valuation study, used to convert health status instrument responses into a single score.
• Time Trade-OffA health state valuation method asking how many years in full health a respondent would consider equal to a longer period in an impaired state.
• UtilityUtility is a numerical measure of preference; in health economics, a health utility values a health state on a scale where 1 is full health and 0 is dead.
• Utility WeightA numerical value representing the relative desirability of a specific health state, used to weight time in that state for QALYs.
• Value SetThe complete collection of utility weights from a population valuation study, used to convert every combination of instrument responses into a utility score.
• Value Set DevelopmentThe process of designing, conducting, and analysing a population valuation study to produce a scoring algorithm for a health status instrument.
• Visual Analogue ScaleA health state valuation method in which respondents mark a perceived health state on a continuous line anchored between worst and best imaginable health.