Historical Control
Historical control is a comparison group of past patients, from earlier trials or registries, used instead of or alongside a concurrently randomised group.
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.
Horizontal Equity
Horizontal equity is equal treatment of equals in health care: equal care for people in equal need and equal payments from those with equal ability to pay.
Hosmer-Lemeshow Test
The Hosmer-Lemeshow test is a goodness of fit test for logistic risk models that compares observed and predicted events in patient groups ranked by risk.
Human Capital Approach
The human capital approach values production lost to illness, disability or early death as the paid and unpaid output the person would have produced.
Hyperbolic Discounting
Hyperbolic discounting is time preference in which the discount rate falls as delay grows, so plans made for later are often reversed when the time comes.
Hypothesis Testing
Hypothesis testing is a statistical method that uses study data to decide whether to reject a stated null hypothesis, such as no difference in mean cost.
I-Squared
I-squared (I2) is the percentage of variation in effect estimates across studies in a meta-analysis that is due to heterogeneity rather than chance.
ICECAP-A
ICECAP-A is a self-report capability wellbeing measure for adults, with five attributes scored on UK index values, for economic evaluation beyond health.
ICECAP-O
ICECAP-O is a five-attribute capability wellbeing measure for people aged 65 and over, with UK index values for evaluating health and social care.
ICHOM Standard Set
An ICHOM Standard Set is an agreed set of outcomes and case-mix variables for one medical condition, used to compare providers on the value of care.
Immortal Time
Immortal time is follow-up in an observational study during which, because of how treatment groups are defined, patients cannot have the outcome studied.
Importance Sampling
Importance sampling is a Monte Carlo method that samples rare or influential model inputs more often, then reweights draws so estimates match the model.
Impoverishing Health Expenditure
Impoverishing health expenditure is out-of-pocket health spending that pushes a household below a poverty line, or deeper into poverty if already poor.
Imputation
Imputation replaces missing values in a dataset, such as unrecorded trial costs or EQ-5D scores, with estimated values so every record can be analysed.
Incentive Compatible Mechanism
An incentive compatible mechanism is a mechanism design rule under which each player, such as a hospital or survey respondent, does best by being truthful.
Incidence
Incidence is the number of new cases of a disease arising in a population at risk over a set period, used to size patient groups and set model event rates.
Incidence Rate Ratio
The incidence rate ratio (IRR) compares event rates per person-year between two groups, the relative effect used for repeated events in trials and HTA.
Income Elasticity of Demand
Income elasticity of demand is the percentage change in demand for a good, such as health care, divided by the percentage change in income.
Incremental Cost
Incremental cost is the difference in expected total cost between a healthcare option and its comparator, the numerator of the ICER in economic evaluation.
Incremental Cost-Effectiveness Ratio (ICER)
The incremental cost-effectiveness ratio (ICER) is a treatment's extra cost divided by its extra health gain versus a comparator, such as cost per QALY.