Present Value
The current worth of a future sum of money or cash flow stream, found by discounting each future amount using a specified discount rate.
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.
Pressure Ulcer Rate
A measure of how frequently hospitalised patients develop pressure ulcers, or bedsores, a nursing care quality and prevention indicator.
Prevalence
The total proportion of a population with a particular condition at a given time, covering both new and pre-existing cases.
Prevalence Difference
The absolute difference in the prevalence of a condition between two groups, giving a direct measure of disparity in disease burden.
Prevalence Ratio
A measure comparing the prevalence of a condition between two groups, calculated as the ratio of one group's prevalence to the other's.
Prevented Fraction
The proportion of disease cases avoided in a population due to a protective exposure or intervention, the counterpart to the attributable fraction.
Price Elasticity of Demand
A measure of how responsive quantity demanded is to a price change, calculated as percentage change in quantity over percentage change in price.
Price Elasticity of Healthcare
An empirical estimate of how sensitive healthcare use is to changes in out-of-pocket price, most famously quantified by a large randomised experiment.
Principal Agent Model
A formal framework analysing situations where a principal delegates decisions to an agent whose interests may not fully align with their own.
Principal Component
In principal component analysis, a derived variable combining original observed variables to capture the maximum possible variance, uncorrelated with prior components.
Principal-Agent Problem
The difficulty arising when an agent's actions cannot be fully observed by the principal, creating an incentive for the agent to serve their own interest.
Principal-Agent Problem in Healthcare
The specific version of the principal-agent problem in the physician-patient relationship, where clinical expertise gaps create both helpful guidance and risk of distorted recommendations.
Prior Distribution
In Bayesian statistics, the probability distribution representing existing beliefs about a parameter before observing new data.
Prior Odds
The odds that a hypothesis is true before incorporating new evidence, the starting point for Bayesian updating alongside a likelihood ratio.
Prior Probability
The probability assigned to a hypothesis before accounting for new evidence, representing existing belief later updated through Bayesian analysis.
Probabilistic Analysis
An analysis in which uncertain inputs are represented by probability distributions rather than fixed values, and the model runs repeatedly with sampled values.
Probabilistic Sensitivity Analysis
A method characterising overall model uncertainty by assigning probability distributions to inputs and running the model repeatedly with randomly sampled values.
Probability
A numerical measure, ranging from zero to one, expressing the likelihood that a specific event will occur.
Probability of Cost-Effectiveness
The likelihood, given uncertainty in the cost and effect estimates, that an intervention's ICER falls below a specified willingness-to-pay threshold.
Probability-to-Rate Conversion
The mathematical transformation converting a probability of an event over a discrete time interval into its corresponding continuous-time hazard rate.