Poisson Distribution
The Poisson distribution is a probability model for counts of events, such as hospital admissions, that occur independently at a constant rate over time.
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.
Concepts, entries and ontology terms
A concept page is a published entry on the wiki. Some concepts also have a full encyclopaedia article. The Health Economics Ontology (HEO) holds every concept, including dictionary terms without an article, so it is larger than the list of published pages. The knowledge graph shows how concepts relate to each other.
Poisson Regression
Poisson regression models counts of health care events, such as admissions, as rates that change multiplicatively with patient and treatment factors.
Population
Population, in health economic evaluation, is the group of people a decision or analysis concerns, defined by condition, characteristics and care pathway.
Population EVPI
Population EVPI is the expected value of perfect information scaled up to all patients a health care decision will affect, discounted over its lifetime.
Positive Economics
Positive economics is the branch of economics that explains and predicts what is, such as how a sugar tax changes purchases, not what ought to be.
Positive Externality
A positive externality is an uncompensated benefit, such as lower infection risk for others after vaccination, that an activity gives to third parties.
Posterior Distribution
The posterior distribution is the probability distribution of an uncertain model input, such as a treatment effect, after a prior is updated with new data.
Precision Medicine
An approach to prevention, diagnosis or treatment that uses relevant individual or disease characteristics to select a more appropriate care strategy.
Preference
A preference is a comparative evaluation by which a person ranks one option above, below or equal to another, the basis of health utilities and WTP.
Present Value
Present value is what a future cost or health gain, or a stream of them, is worth today, found in economic evaluation by discounting each year's amount.
Price Elasticity of Demand
Price elasticity of demand is the percentage change in quantity demanded after a 1% price rise, used to forecast how patient charges change use of care.
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
A principal component is an uncorrelated linear combination of centered variables whose loading vector identifies a successive direction of maximum variance in the data.
Principal-Agent Problem
The principal-agent problem arises when patients or payers rely on providers who know more than they do, act unobserved and may pursue other interests.
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
A prior distribution is the probability distribution for an uncertain model input, such as a treatment effect, before new data enter a Bayesian analysis.
Probabilistic Sensitivity Analysis
Probabilistic sensitivity analysis (PSA) runs a decision model many times on jointly drawn inputs to estimate expected outcomes and decision uncertainty.
Probability
Probability is a number between 0 and 1 showing how likely an event is, used in health economic models to weight costs and QALYs and express uncertainty.
Probability of Cost-Effectiveness
The probability of cost-effectiveness is the chance, given current evidence, that an intervention has the highest mean net benefit at a stated threshold.
Producer Surplus
Producer surplus is the gain suppliers of health care, such as drug makers, make by selling each unit at a price above the least they would have accepted.