Utility
A numerical representation of the satisfaction, wellbeing, or preference an individual derives from a particular outcome, state, or good.
Encyclopaedia
Explore comprehensive, evidence-informed explanations of key health economics concepts, including their development, application and relationships to other concepts. Published entries are validated through human expert review.
Utility Function
A mathematical representation of preferences that assigns a numerical value to each possible outcome, so higher-utility outcomes are preferred.
Utility Maximisation
The behavioural assumption that individuals make choices intended to achieve the highest possible satisfaction given their preferences and constraints.
Utility Weight
A numerical value representing the relative desirability of a specific health state, used to weight time in that state for QALYs.
Vaccine Effectiveness
The degree to which a vaccine reduces disease risk under real-world conditions in a general population, unlike efficacy measured under trial conditions.
Vaccine Efficacy
The degree to which a vaccine reduces disease risk among vaccinated individuals under the controlled conditions of a clinical trial.
Value of Information
A framework quantifying the expected benefit of reducing decision uncertainty, comparing expected outcomes under current uncertainty against outcomes if it were resolved.
Value of Information Analysis
The application of value of information methods to a health economic decision, typically used to judge whether further research is worth conducting.
Value of Statistical Life
A monetary estimate of the value society places on reducing the risk of death, derived from willingness to pay for a small risk reduction.
Value of Statistical Life Year
An adaptation of the value of statistical life expressed per life-year rather than per life, adjusted for age and remaining life expectancy.
Value Set
The complete collection of utility weights from a population valuation study, used to convert every combination of instrument responses into a utility score.
Value Set Development
The process of designing, conducting, and analysing a population valuation study to produce a scoring algorithm for a health status instrument.
Variance
A dispersion measure representing the average squared deviation of individual data points from the mean of a dataset.
Variance Analysis
A technique for decomposing the difference between budgeted and actual financial results into component causes, such as price and volume effects.
Variance Inflation Factor
A regression diagnostic quantifying how much an estimated coefficient's variance is inflated by correlation with other predictors, higher values meaning worse multicollinearity.
Variance Reduction
Statistical techniques, including antithetic variates and control variates, used to reduce a Monte Carlo simulation's statistical variability for a given number of iterations.
Variance-Based Sensitivity
Global sensitivity analysis techniques, including Sobol indices, decomposing total output variance into components attributable to each parameter and their interactions.
Variance-Covariance Matrix
A table showing each parameter's variance and the covariance between each pair, summarising both individual uncertainty and interdependence among model inputs.
Variation
Differences observed in a healthcare process or outcome across patients, providers, or time periods, either legitimate or reflecting inconsistent quality.
Varimax Rotation
An orthogonal factor rotation maximising the variance of squared loadings within each factor, tending to make each variable load strongly on only one factor.