Comparator
The alternative intervention, treatment, or strategy against which a new option is evaluated in an economic evaluation.
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.
Compartmental Model
A modelling approach dividing a population into distinct compartments, such as susceptible, infected, and recovered, and tracking flow between them over time.
Compensating Variation
A monetary measure of the change in wellbeing from a price or policy change, the sum needed after the change to restore original utility.
Competing Risks
A situation where a person is at risk of more than one type of event, so one event's occurrence prevents another from ever happening.
Complaint Rate
A measure of how frequently patients or families formally express dissatisfaction with the care or service received within an organisation.
Complication Rate
A measure of how frequently a specific adverse outcome occurs within a defined patient population undergoing a particular procedure.
Computational Complexity
A measure of the computational resources required by an algorithm as the size of the input increases.
Concentration Curve
A graphical tool plotting the cumulative share of a health variable against the cumulative population share ranked poorest to richest.
Concentration Index
A summary measure of socioeconomic health inequality derived from the concentration curve, ranging from negative one to positive one.
Concurrent Risk Adjustment
A risk adjustment method using diagnoses observed in the same period costs are predicted for, unlike prospective adjustment using prior period data.
Condition Index
A diagnostic detecting problematic collinearity among predictor variables, calculated from the eigenvalues of the predictor matrix, larger values meaning worse collinearity.
Conditional Probability
The probability that an event will occur given that another specified event has already occurred, calculated from their joint probability.
Conditioning
The sensitivity of a mathematical problem to small changes in its input data or numerical calculations.
Confidence Ellipse
A graphical region, typically on a cost-effectiveness plane, showing where the true joint value of incremental cost and effect is expected to fall.
Confidence Interval
A range of values, calculated from sample data, expected to contain the true population parameter with a specified level of confidence.
Confidence Interval Estimation
The statistical process of calculating a range of plausible values for an unknown parameter based on sample data and a specified confidence level.
Confirmatory Factor Analysis
A technique testing whether a hypothesised factor structure adequately explains observed correlations among measured variables, unlike exploratory factor analysis.
Conjoint Analysis
A method for measuring how individuals value different attributes of a good or service by analysing their evaluations of combined alternatives.
Constant Hazard
A survival pattern where the instantaneous risk of an event stays the same at every point in time, matching an exponential distribution.
Constrained Optimisation
A mathematical approach to finding the best outcome, such as maximum health benefit, subject to limiting conditions, such as a fixed budget.