Relapse-Free Survival
A time-to-event measure defined as the time from treatment completion until disease recurrence or death, used for curative-intent treatments.
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.
Relative Dose Intensity
A measure comparing the dose intensity a patient actually received to the originally planned, full dose intensity, expressed as a percentage.
Relative Error
The absolute error expressed as a proportion or percentage of the true or accepted value.
Relative Risk
A measure calculated as the ratio of the risk of an outcome in an exposed or treated group to that in an unexposed group.
Relative Risk Reduction
The proportional reduction in risk associated with a treatment, calculated as one minus the relative risk, expressed as a percentage.
Relative Survival
A survival measure comparing observed survival in a population to expected survival in a comparable general population, without needing cause-of-death data.
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.
Relative Value Scale
A system assigning a numerical value to each service reflecting its relative resource intensity, providing the structure for a standardised fee schedule.
Relative Value Unit
A unit quantifying resources required for a US Medicare service, incorporating physician work, practice expense, and malpractice risk components.
Relative Weight
A numerical value assigned to a payment classification, such as a diagnosis-related group, reflecting its expected resource intensity relative to average.
Repeated Measures Analysis
A statistical approach analysing data in which the same outcome has been measured multiple times on the same individuals, accounting for correlation.
Reproduction Number
A general term for the average number of secondary infections one infected individual produces, covering both the basic and effective reproduction numbers.
Residual
The difference between an observed value and the value predicted for it by a fitted statistical model.
Residual Analysis
A statistical technique examining the differences between a model's predicted values and observed data, checking for systematic patterns left unexplained.
Resource-Based Relative Value
A methodology determining physician reimbursement based on a standardised measure of resources required, incorporating work, practice expense, and malpractice risk.
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.
Responsiveness
The ability of a health outcome measure to detect a clinically meaningful change in health status over time when one has genuinely occurred.
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.