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.
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.
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.
Return on Assets
A financial ratio calculated as net income divided by total assets, showing how efficiently an organisation uses its assets to generate profit.
Return on Equity
A financial ratio calculated as net income divided by owner equity, showing the return generated on capital invested by an organisation's owners.
Return on Investment
A measure of an investment's profitability, calculated as the net gain from the investment divided by its cost.
Reynolds-Smolensky
An index measuring the redistributive effect of a tax or transfer system, calculated as the difference between pre-tax and post-tax income Gini coefficients.
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.
Robust Standard Error
An estimate of a regression coefficient's statistical uncertainty that remains valid even when standard modelling assumptions, such as constant error variance, are violated.
ROC Curve
A graph depicting the trade-off between a test's true positive rate and false positive rate across a full range of decision thresholds.
Rollback
An alternative term for folding back, the process of solving a decision tree by working backward from final outcomes to the initial node.
Root Mean Square Error
A measure of average prediction error, the square root of the average squared difference between predicted and observed values, in the outcome's units.
Rounding Error
The difference introduced when a numerical value is rounded to fit a limited number of digits.
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.
Sample Size Calculation
The process of determining the number of participants a study needs to have an adequate chance of detecting a specified treatment effect.
Sandwich Estimator
A method calculating an estimator's variance that remains valid even when standard model assumptions are violated, forming the basis of robust standard errors.
Scale Efficiency
A measure of whether a provider is operating at its optimal size, distinct from whether it uses its current scale of inputs efficiently.
Scaled Schoenfeld
A diagnostic technique testing the proportional hazards assumption by scaling Schoenfeld residuals by their variance to improve test power.