Relative Survival Model
A statistical model estimating disease-specific survival by comparing observed survival against expected general population survival, without individual cause-of-death data.
Encyclopaedia
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Residual Analysis
A statistical technique examining the differences between a model's predicted values and observed data, checking for systematic patterns left unexplained.
Response Surface
A fitted mathematical approximation describing how a model's output varies with its inputs, built from limited runs and used to predict untested combinations.
Response Surface Methodology
Statistical techniques for modelling and optimising the relationship between several inputs and an output by fitting a smooth surface to limited results.
Restricted Cubic Spline
A flexible function of piecewise cubic segments joined smoothly at knots, constrained to behave linearly beyond the outermost knots.
Restricted Cubic Splines
A collection of piecewise cubic functions joined at knots and constrained to extend linearly beyond the data range, used to model non-linear hazard shapes.
Restricted Mean Survival Time
A survival summary measure calculated as the area under the survival curve up to a specified time point, an alternative to the hazard ratio.
Right Censoring
The most common form of censoring, occurring when follow-up ends or a patient is lost before the event of interest has occurred.
Robust Optimisation
An optimisation approach seeking a solution that performs well across a range of possible uncertain parameter values, rather than one best-guess scenario.
Rollback
An alternative term for folding back, the process of solving a decision tree by working backward from final outcomes to the initial node.
Royston-Parmar Model
A class of flexible parametric survival models using restricted cubic splines to represent a transformed survival or hazard function while remaining fully parametric.
Scaled Schoenfeld
A diagnostic technique testing the proportional hazards assumption by scaling Schoenfeld residuals by their variance to improve test power.
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.
SEIR Model
An extension of the basic epidemic model adding an exposed compartment for individuals infected but not yet infectious, before they become infectious.
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.
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.
Shared Frailty
An extension of the frailty model in which individuals within the same group are assumed to share a common unobserved risk effect.