Healthy Life Expectancy
A population health measure expressing the average years an individual is expected to live in good health, adjusting for time in disability.
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.
Healthy Year 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.
Hedges' G
A standardised effect size measure similar to Cohen's d but corrected for small sample size bias.
Herd Immunity Threshold
The proportion of a population that must be immune to achieve herd immunity, mathematically related to a pathogen's basic reproduction number.
Heterogeneity Assessment
A statistical evaluation of how much effect estimates vary across studies in a meta-analysis, commonly quantified using the I-squared statistic.
Heterogeneous Treatment Effect
Variation in the size or direction of a treatment's effect across individuals or subgroups, so the overall average may not fit any one patient.
Hidden Markov Model
A statistical model in which the true underlying state cannot be directly observed, only indicated indirectly and probabilistically by observable data.
Hierarchical Condition Category
A US Medicare Advantage risk classification system grouping diagnosis codes into hierarchical, clinically related categories to predict future healthcare costs.
Hierarchical Model
A modelling approach representing nested data, such as patients within hospitals, allowing effects to vary at each level while borrowing statistical strength.
Hierarchical Testing
A multiple testing strategy organising hypotheses into a prespecified sequence, so later tests are only conducted if earlier, higher-priority tests succeed.
Hosmer-Lemeshow Test
A goodness of fit test assessing how well a logistic regression model's predicted probabilities match observed outcome frequencies across risk groups.
Human Capital Approach
A method for valuing productivity lost to illness, disability, or premature death, based on the market wages the person would otherwise have earned.
Human Capital Method
A method valuing illness or death's economic cost based on the market wages the affected individual would otherwise have earned.
Hyperbolic Discounting
A pattern of time preference in which people discount the near future more steeply than the distant future, unlike constant exponential discounting.
Hypothesis Testing
A formal framework for evaluating whether observed data provide enough evidence to reject a null hypothesis in favour of an alternative.
I-Squared
A statistic quantifying the percentage of total variation across studies in a meta-analysis attributable to genuine heterogeneity rather than chance.
Ill-Conditioned Matrix
A matrix for which small changes in its elements or input values can produce disproportionately large changes in the computed solution.
Immortal Time
A period of follow-up during which, due to how exposure groups were defined, a participant could not possibly have experienced the outcome.
Importance Sampling
A variance reduction technique for Monte Carlo simulation that deliberately oversamples important regions of a distribution, then reweights the samples to correct for this.
Impoverishing Health Expenditure
Out-of-pocket healthcare spending that pushes household income or consumption below an established poverty line, or further below it.