Numerical Optimisation
Computational techniques for finding the input values that minimise or maximise an objective function when no analytical solution is available.
Encyclopaedia
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Numerical Stability
The property of a numerical method that limits the growth and amplification of rounding and computational errors during calculations.
Objective Response Rate
The proportion of patients whose tumour shrinks by a predefined amount or disappears entirely following treatment, measured using standardised radiological criteria.
Oblique Rotation
A factor analysis technique transforming a solution into a more interpretable structure while allowing the resulting factors to correlate with each other.
Observed-to-Expected Ratio
A measure comparing a provider's actual observed outcomes against statistically expected numbers given patient severity, above one meaning worse than expected.
Occupancy Rate
A measure of the proportion of available beds or capacity within a facility actually in use at a given time.
Odds Ratio
A measure comparing the odds of an outcome in one group to the odds in another, common in case-control studies and logistic regression.
One-Stage Meta-Analysis
An individual patient data meta-analysis analysing combined patient-level data from all studies within a single unified statistical model.
One-Tailed Test
A hypothesis test assessing evidence for an effect in only one specified direction, requiring strong prior justification for that direction.
One-Way Sensitivity
A sensitivity analysis in which a single input parameter is varied across a range while all others are held at their base case values.
One-Way Sensitivity Analysis
An analysis varying a single input parameter across its plausible range, one at a time, to assess its individual effect on cost-effectiveness results.
Operating Cost
The recurring cost of an organisation's ongoing operations, such as staffing, supplies, and utilities, as distinct from one-off capital investment.
Operating Margin
A financial ratio calculated as operating income divided by revenue, showing the proportion remaining after operating expenses but before non-operating items.
Opportunity Cost
The value of the next best alternative forgone when a resource is allocated to a particular use.
Opportunity Loss
The difference in value between the outcome of the optimal decision and the outcome of the decision actually made under uncertainty.
Optimal Sample Size
The sample size for a proposed study that maximises the expected net benefit of sampling, balancing information value against rising cost.
Ordinal Scaling
A measurement scale property in which values can be ranked but numerical differences do not necessarily reflect equal differences in the underlying quantity.
Orthogonal Design
An experimental design for a choice experiment in which attribute levels are varied independently, so each attribute's effect on preference can be separated statistically.
Orthogonal Rotation
A factor analysis technique transforming a solution into a more interpretable structure while constraining the resulting factors to remain uncorrelated.
Outlier
An observation differing markedly from other values in a dataset, either from genuine unusual variation or a measurement or entry error.