Separating Equilibrium
A market outcome in which different risk types choose different options, revealing their true type to the other party in the transaction.
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.
Sequential Analysis
A statistical approach evaluating data as it accumulates, allowing early stopping once a predefined level of evidence is reached, rather than a fixed sample size.
Sequential Monte Carlo
A class of algorithms, including particle filtering, estimating a sequence of unknown quantities over time by updating weighted samples as new data arrive.
Sequential Sampling
A data collection approach in which the decision to continue or stop sampling is made based on accumulating data, rather than a fixed sample size.
Shadow Price
The implicit value of a resource with no observable market price, reflecting the opportunity cost of using it in a particular way.
Shadow Price of Health
The implicit value of health gains forgone when a health budget is spent inefficiently, used as a basis for setting a cost-effectiveness threshold.
Shared Frailty
An extension of the frailty model in which individuals within the same group are assumed to share a common unobserved risk effect.
Signaling
An action taken by an informed party to credibly convey private information to an uninformed party that could not otherwise be verified.
Signaling Theory
A body of theory analysing how individuals with private information take costly actions to credibly reveal it in markets with information asymmetry.
Significance Level
The predetermined probability threshold, usually five percent, used to judge whether a result counts as statistically significant.
Simplex Method
An optimisation algorithm that solves linear programming problems by moving systematically between feasible solutions until the optimum is found.
Simpson Method
A numerical integration technique approximating a definite integral by fitting a series of parabolic segments to the function, more accurate than linear approximation.
Simpson Paradox
A statistical phenomenon where a trend seen within subgroups reverses or disappears once those subgroups are combined into a single aggregated analysis.
Simpson Rule
A numerical integration technique approximating a definite integral by fitting a series of parabolic curves to the function being integrated.
Simulated Annealing
An optimisation technique modelled on slowly cooling metal, occasionally accepting worse solutions during search to avoid becoming trapped in a poor local solution.
Simulated Treatment Comparison
A method comparing treatments from separate trials by fitting a regression model to one trial's data to predict outcomes for the other's population.
Simulation Method
A general approach to estimating a model's results by repeatedly running it computationally, rather than solving for results using closed-form equations.
Single Attribute Utility
A utility value derived from a single dimension of health or outcome, unlike multi-attribute utility, which integrates several dimensions.
Singular Value Decomposition
A matrix factorisation method that separates a matrix into orthogonal components and singular values representing its principal directions and scaling.
SIR Model
A basic epidemic model dividing a population into susceptible, infectious, and recovered compartments, representing flow between them using differential equations.