Dynamic Transmission Model
An epidemiological model representing how infection risk for a susceptible individual depends on current population prevalence, capturing feedback such as herd immunity.
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.
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.
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.
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 of Partial Perfect Information
The maximum value of completely resolving uncertainty in a specific subset of a model's parameters, while other parameters remain uncertain.
Expected Value of Perfect Information
The maximum amount a decision-maker should pay to eliminate all uncertainty surrounding a technology decision, comparing outcomes under perfect versus existing information.
Expected Value of Sample Information
The expected benefit of conducting a specific, finite study with a defined sample size and design, only partially resolving existing uncertainty.
Exponential Distribution
A probability distribution characterised by a constant hazard rate over time, used to model event timing when risk is assumed not to change.
Exponential Model
A survival model assuming time-to-event data follow an exponential distribution, implying a constant hazard rate throughout the modelled time horizon.
Extrapolation
The process of projecting a clinical outcome, such as survival, beyond a trial's observed follow-up period, typically using a fitted parametric model.
Extreme Value Analysis
A statistical approach characterising the behaviour of the most extreme, rather than typical, values a variable can take, based on extreme value distribution theory.
First-Order Index
A variance-based sensitivity measure, also called a Sobol index, quantifying the share of a model's output variance from a single parameter varying alone.
Fleming-Harrington Estimator
A statistical technique for estimating the survival function from censored data, more flexible than the Kaplan-Meier estimator in weighting events over time.
Fleming-Harrington Test
A hypothesis test comparing survival distributions between groups, generalising the log-rank test by allowing different weights for events at different follow-up times.
Flexible Parametric Model
A class of survival models using flexible functions, such as restricted cubic splines, to represent the hazard or survival function beyond standard distributions.