Eigenvector
A non-zero vector whose direction remains unchanged when transformed by a matrix, although its magnitude may be scaled.
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.
Elastic Demand
A condition in which quantity demanded changes proportionally more than a given price change, indicating consumers are relatively sensitive to price.
ENBS Calculation
The process of computing the expected net benefit of sampling, the expected value of sample information from a study minus its expected cost.
Equilibrium
A state in an economic system where opposing forces, such as supply and demand, balance so there is no inherent tendency to change.
Equilibrium Price
The price at which the quantity consumers wish to buy equals the quantity producers wish to sell, clearing the market.
Equity
The principle of fairness in the distribution of health, healthcare, and the resources and opportunities that shape them, recognising that different needs may justify different treatment.
Equity-Weighted Analysis
An economic evaluation that applies differential weights to health gains in different population groups, giving greater weight to gains for disadvantaged groups.
Equivalent Variation
A monetary measure of the change in wellbeing from a price or policy change, the sum needed before the change to match post-change welfare.
Error Propagation
The process by which uncertainties or numerical errors accumulate and influence the results of subsequent calculations.
Event Probability
The likelihood that a specific clinical or economic event will occur within a defined period, used as an input across decision-analytic models.
Event Queue
The ordered list of scheduled future events awaiting execution within a discrete event simulation, sorted by the time each is due to occur.
Excess Hazard
The additional death risk attributable specifically to the disease studied, the difference between total observed hazard and the background hazard in a comparable population.
Exchangeable Correlation
A correlation structure for repeated measures assuming any two observations within the same cluster are equally correlated, regardless of their timing or order.
Expansion Path
The set of cost-minimising input combinations as output rises, holding relative input prices constant.
Expected Loss
The probability-weighted average cost of making an incorrect decision under uncertainty, calculated across all possible states and their probabilities.
Expected Net Benefit
Expected net benefit is the average net benefit of an alternative across the uncertainty represented in an economic evaluation, calculated at a stated cost-effectiveness threshold.
Expected Net Benefit of Sampling
A research prioritisation measure calculated as the expected value of sample information from a study minus the expected cost of conducting it.
Expected Utility
The probability-weighted average of the utility of each possible outcome of a decision under uncertainty, used to identify a rational preferred option.
Expected Value
The probability-weighted average of all possible outcomes of an uncertain event, found by multiplying each outcome by its probability and summing.
Expected Value Analysis
An approach to decision-making under uncertainty that evaluates options based on the probability-weighted average of their possible outcomes.