Arrow's Impossibility Theorem
Arrow's impossibility theorem is a welfare economics theorem proving no rule can pool rankings of three or more health options and meet five basic tests.
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.
Concepts, entries and ontology terms
A concept page is a published entry on the wiki. Some concepts also have a full encyclopaedia article. The Health Economics Ontology (HEO) holds every concept, including dictionary terms without an article, so it is larger than the list of published pages. The knowledge graph shows how concepts relate to each other.
Assumption Structure
Assumption structure is the full set of simplifying assumptions in a health economic model's design, such as its health states, events and extrapolation.
Asymptotic Normality
Asymptotic normality means an estimator's sampling distribution is approximately normal in large samples, the basis of Wald confidence intervals.
Atkinson Index
The Atkinson index measures inequality in health or income using a social welfare function with an explicit inequality aversion parameter, epsilon.
Attributable Cost Estimation
Attributable cost estimation measures the extra healthcare cost a disease or risk factor causes, against what the same patients would cost without it.
Auction Theory
Auction theory in health economics studies how bidding rules in tenders set the price and supply of medicines, vaccines and medical equipment.
Autoregressive Correlation
Autoregressive correlation is a structure for repeated measures in which correlation falls by a constant factor with each time step between measurements.
Available Case Analysis
Available case analysis is a missing data method estimating each quantity from everyone with data for it, so costs and QALYs may use different patients.
Average Cost
Average cost is total cost divided by the number of units produced, such as patients treated or bed days, giving the cost per unit of a health service.
Average Cost-Effectiveness Ratio
The average cost-effectiveness ratio (ACER) is an option's cost per unit of health effect, in total or against doing nothing, without comparing options.
Avoidable Cost
Avoidable cost is the cost a budget holder would no longer pay if a health service stopped or a disease was prevented, within a stated time period.
Background Mortality
Background mortality is the death rate a model's patients would face without the disease, usually taken from general population life tables by age and sex.
Bargaining Theory
Bargaining theory explains how negotiating parties divide the gains from reaching agreement, as when a payer and a manufacturer agree a drug price.
Base Case
The base case is a model's preferred set of inputs and assumptions and the primary results they produce, against which sensitivity analyses are compared.
Baseline Risk
Baseline risk is the probability of an event without the intervention under study; models apply relative treatment effects to it to give absolute benefit.
Bathtub Hazard
A bathtub hazard is a U-shaped hazard that is high soon after an event such as surgery, falls to a lower stable level, then rises again as patients age.
Baumol Effect
The Baumol effect is the rising relative cost of labour-intensive services such as health care as their pay tracks faster productivity growth elsewhere.
Bayesian Analysis
Bayesian analysis updates a prior distribution with data via Bayes' theorem to give a posterior, used in HTA for evidence synthesis and decision models.
Bayesian Analysis CEA
Bayesian cost-effectiveness analysis updates prior evidence on costs and health effects with new data to estimate net benefit and decision uncertainty.
Bayesian Information Criterion
Bayesian information criterion (BIC) ranks models fitted to the same data, such as HTA survival curves, by fit with a penalty that grows with sample size.