Demand
The quantity of a good or service consumers are willing and able to purchase at a given price over a specified period.
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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.
Demand Curve
A graph showing the relationship between price and quantity demanded, typically sloping downward as consumers buy less when price rises.
Demand for Health
An economic framework in which individuals demand health as a valued and productive stock, while healthcare, personal time and other inputs are demanded partly because they can maintain or improve that stock.
Departure Process
The pattern by which entities, such as patients, leave a discrete event simulation after completing the services or processes being modelled.
Derived Demand for Healthcare
The concept that demand for healthcare is not valued for its own sake but derives from an underlying demand for health itself.
Design Effect
A statistic quantifying how much a complex survey or clustered study's variance differs from what a simple random sample of the same size would give.
Deterministic Model
A model in which all input parameters take single, fixed values, producing one point estimate of cost and effect, unlike a probabilistic model.
Deterministic Sensitivity Analysis
A sensitivity analysis varying one or more inputs at a time to fixed alternative values, holding others at base case, to observe the effect.
Deviance Residual
A model residual, used with generalised linear and survival models, constructed so its sum of squares equals the model's overall deviance statistic.
DFBETA
A regression diagnostic measuring how much a coefficient would change if a particular observation were removed, identifying disproportionately influential data points.
DFBETAS
A standardised version of the DFBETA diagnostic, scaled by its standard error, allowing influence of observations to be compared consistently across models.
Diagnostic Accuracy
The overall ability of a diagnostic test to correctly classify individuals as having or not having a condition, summarised using sensitivity and specificity.
Differential Discounting
The practice of applying different discount rates to costs and health outcomes within an economic evaluation, rather than discounting both at the same rate.
Dirichlet Distribution
A multivariate distribution representing uncertainty in a set of proportions that must sum to one, such as transition probabilities from a state.
Discount Rate
The annual percentage applied to future costs or health outcomes to express them in present-value terms and permit consistent comparison across time.
Discounting Costs
The application of a discount rate to future costs within an economic evaluation, converting them into a common present-day value.
Discounting Health
The application of a discount rate to future health outcomes within an economic evaluation, converting them into a common present-day value.
Discrete Choice Experiment
A quantitative technique for eliciting preferences in which respondents choose among hypothetical alternatives defined by varying attributes and levels.
Discrete Event Model
A simulation model representing a system as a sequence of distinct events at specific times, with the system's state changing only at each event.
Discrete Event Simulation
A simulation technique tracking individual entities through a sequence of discrete events, with the clock advancing directly from one event to the next.