Scarcity
The fundamental economic condition in which available resources are insufficient to satisfy all competing wants and needs.
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.
Scenario Analysis
A form of sensitivity analysis examining how results change under a small number of alternative, internally consistent assumption sets, rather than varying parameters independently.
Schoenfeld Residual
A residual specific to the Cox model, calculated at each event time, used to test whether the proportional hazards assumption holds.
Scope Efficiency
A measure of whether producing multiple services jointly within one organisation is more efficient than producing them separately across different organisations.
Screening Theory
A body of theory analysing how an uninformed party can design a menu of options that leads individuals to reveal their private information through choice.
SEIR Model
An extension of the basic epidemic model adding an exposed compartment for individuals infected but not yet infectious, before they become infectious.
Selection Model
A missing data modelling approach explicitly modelling the process by which observations become missing, alongside the model for the outcome itself.
Semi-Parametric Survival
A category of survival models, notably the Cox model, that assumes covariate effects parametrically while leaving the baseline hazard unspecified.
Sensitivity Analysis
A general term for any technique assessing how a model's results change in response to variation in its inputs or structural assumptions.
Separating Equilibrium
A market outcome in which different risk types choose different options, revealing their true type to the other party in the transaction.
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.
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.
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 Rule
A numerical integration technique approximating a definite integral by fitting a series of parabolic curves to the function being integrated.