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.
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.
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.
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.
VOI Analysis
An abbreviation for value of information analysis, applying formal decision-theoretic methods to quantify the expected benefit of reducing decision uncertainty.
Wald Test
A statistical test assessing whether an estimated parameter differs significantly from a specified value, based on the ratio of estimate to standard error.
Weak Dominance
A situation where an intervention is inferior not to any single alternative but to a combination of two other available options.
Weibull Distribution
A flexible probability distribution capable of a monotonically increasing or decreasing hazard rate depending on its shape parameter.
Weibull Model
A survival model based on the Weibull distribution, representing an increasing or decreasing hazard over time, though restricted to a monotonic pattern.
Weighted Log-Rank
A class of tests comparing survival distributions using different weights at different follow-up times, including the log-rank, Peto, and Tarone-Ware tests.
Wilcoxon Test
A test comparing survival distributions that gives greater weight to earlier event times than later ones, unlike the standard log-rank test.
Willingness to Accept
The minimum compensation an individual would require to voluntarily give up a good or accept a worse outcome.
Willingness to Pay
The maximum amount of money an individual would give up to obtain a good or avoid a negative outcome.
Willingness-to-Pay Estimation
The empirical process of measuring willingness to pay, typically through stated preference methods such as contingent valuation or discrete choice experiments.
Willingness-to-Pay Threshold
The maximum amount a decision-maker is prepared to pay for an additional unit of health benefit, used to judge acceptable value for money.
Within Subject Variation
The degree to which repeated measurements on the same individual fluctuate over time, unlike between-subject variation reflecting differences across individuals.