Cross-Cultural Validity
Cross-cultural validity is how far items in a translated or culturally adapted health questionnaire, such as the EQ-5D, perform like the original version.
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.
Cross-Price Elasticity
Cross-price elasticity measures how demand for one good responds to a change in another good's price: positive for substitutes, negative for complements.
Cross-Sectional Design
A cross-sectional design is an observational design that measures exposure and outcome in a population at one point in time, often to estimate prevalence.
Cross-Validation
Cross-validation estimates how well a prediction model, such as a cost or risk model, will perform on new data by testing it on data held out from fitting.
Crossover Design
Crossover design is a clinical trial design in which each participant receives two or more treatments in a randomised order and acts as their own control.
Crossover Trial
A trial in which participants sequentially receive two or more treatments under comparison, with each participant's response compared against their own.
Crosswalk
A statistical mapping converting health state scores from one version of an instrument to an equivalent score on another version.
Crowding Out
Crowding out occurs when public spending or intervention displaces private activity that would have happened anyway, reducing the programme's net effect.
Cubic Spline
A cubic spline is a smooth curve made of cubic polynomial pieces joined at knots, used in health economics to fit flexible survival and hazard curves.
Cumulative Hazard
Cumulative hazard, H(t), is the hazard rate summed over time in survival models. Survival equals exp(-H(t)), and unlike a probability H(t) can exceed 1.
Cumulative Incidence
Cumulative incidence, or risk, is the proportion of people free of an event at the start of a period who have it by the end, such as a 5-year stroke risk.
Cumulative Meta-Analysis
Cumulative meta-analysis is a meta-analysis repeated as each new study is added, usually by date, showing how the pooled effect and its uncertainty evolve.
Cure Fraction
The cure fraction is the proportion of patients a survival model expects never to die from their disease, the level at which relative survival plateaus.
Cure Fraction Model
A cure fraction model is a survival model estimating the share of patients cured and the survival of the uncured, used to extrapolate survival in HTA.
Cure Model
A cure model is a survival model in which disease-related excess mortality falls to zero for a share of patients, so the survival curve levels off.
Cure Rate Model
A cure rate model is a survival model that estimates the cure fraction and survival of uncured patients, used in HTA to extrapolate long-term survival.
Curve Fitting
Curve fitting is estimating a mathematical function's parameters to match observed data, as when survival curves are fitted to trial data and extrapolated.
Cycle
A cycle is a defined time interval during which a discrete-time state-transition model updates health-state occupancy and accumulates relevant outcomes and costs.
Cycle Length
Cycle length is the duration of one cycle in a Markov or other discrete-time state-transition model, such as a month or a year, set before the model runs.
D-Efficient Design
A D-efficient design is a discrete choice experiment design chosen for low D-error, giving precise preference estimates under an assumed model.