Dictionary

P

Plan-Do-Study-ActTermPDSA Cycle, Deming Cycle

A structured, iterative four-stage cycle involving planning a change, implementing it small-scale, studying results, and acting on what was learned.

Platform TrialTermMulti-Arm Multi-Stage Trial, Standing-Platform Study

A trial design using one continuously operating master protocol to evaluate multiple treatments over time, letting treatments enter or leave by predefined rules.

Platform Trial DesignTermPlatform Study Design, Perpetual-Trial Design

The structural and statistical framework underlying a platform trial, including shared infrastructure, a common control arm, and rules for adding or dropping treatments.

Platinum PlanTermPlatinum Tier, Platinum Metal Level

A US Affordable Care Act marketplace plan category with the highest standard actuarial value, around ninety percent, giving the highest premiums but lowest cost-sharing.

Plausibility AssessmentTermPlausibility Check, Sense-Check

An evaluation of whether a model's assumptions, structure, or results are reasonable given existing clinical and scientific knowledge, even without formal statistical testing.

Point Allocation MethodConceptPoint Allocation, Constant Sum Method, Constant Sum Allocation, Fixed-Total Allocation, Points Distribution Method

The point allocation method asks respondents to divide a fixed total of points, often 100, among health outcomes or criteria to show their relative value.

Point EstimateConceptSingle-Value Estimate, Best-Guess Estimate

A point estimate is a single numerical value calculated from observed data or a fitted model to represent a specified unknown quantity on a stated scale.

Point of Service PlanTermPOS Plan, Point-of-Service Insurance

A managed care plan combining HMO and PPO features, requiring a primary care provider while still allowing costlier out-of-network care.

Point PrevalenceConceptSnapshot Prevalence, Prevalence at a Single Time

The proportion of a population found to have a particular condition at a single specific point in time, unlike period prevalence or incidence.

Point-of-Care TrialTermPOC Trial, Bedside Randomised Trial

A trial embedded directly within routine clinical care, using existing workflows and electronic records to randomise patients and collect outcome data.

Poisson DistributionConceptPoisson Model, Count Distribution

A discrete probability distribution describing the number of times an event occurs within a fixed interval, assuming independence and a constant average rate.

Poisson RegressionConceptCount Regression, Log-Linear Count Model

A modelling technique analysing count outcome data, such as clinical events per patient, based on the assumption that outcomes follow a Poisson distribution.

Policy EvaluationTermPolicy Appraisal, Policy Assessment

A structured assessment of whether an implemented policy achieved its intended objectives, comparing observed outcomes against what would otherwise have occurred.

Policy ImplementationTermPolicy Rollout, Policy Delivery

The process of putting an adopted policy into actual practice, encompassing the administrative, regulatory, and operational steps required.

Policy Option AssessmentTermOption Appraisal, Policy Alternatives Assessment

The systematic evaluation of alternative approaches to a health policy problem, comparing options across criteria such as cost and equity.

Policy Option IdentificationTermOption Generation, Policy Alternatives Identification

The process of generating a comprehensive set of potential approaches to a policy problem before proceeding to detailed comparative evaluation.

Policy Problem DefinitionTermProblem Framing, Policy Problem Framing

The process of clearly articulating the specific issue a policy is intended to address, including its scope, causes, and affected population.

Policy RecommendationTermPolicy Advice, Recommended Option

A formal proposal advocating a specific course of action to address a defined policy problem, following systematic analysis of alternatives.

Policy RevisionTermPolicy Amendment, Policy Update

A modification to an existing health policy to address shortcomings, incorporate new evidence, or adapt to changed circumstances.

Policy TerminationTermPolicy Cessation, Policy Wind-Down

The formal discontinuation of an existing policy or programme, typically when judged ineffective, unnecessary, or superseded by an alternative.

Political FeasibilityTermPolitical Viability, Political Acceptability

An assessment of whether a policy is likely to garner sufficient political support to be adopted, given stakeholder interests and public opinion.

POLSTTermPhysician Orders for Life-Sustaining Treatment, Portable Medical Order

Physician Orders for Life-Sustaining Treatment, a standardised medical order documenting a seriously ill patient's resuscitation and treatment preferences.

PolypharmacyTermMultiple Medication Use, Concurrent Medication Burden

The concurrent use of multiple medications by a patient, most commonly defined as five or more regularly used medications, though definitions vary.

Pooling EquilibriumTermPooling Outcome, Mixed-Type Equilibrium

A market outcome in which different risk types make the same choice, so a firm cannot distinguish between them from behaviour alone.

PopulationConcept

Population, in health economic evaluation, is the group of people a decision or analysis concerns, defined by condition, characteristics and care pathway.

Population AnalyticsTermPopulation Health Analytics, Cohort Analytics

The application of data analysis to understand health patterns and needs across an entire defined patient population, supporting risk stratification.

Population Attributable FractionConceptPAF, Population Aetiologic Fraction

The proportion of disease cases in an entire population that would not occur if a specific exposure were eliminated, accounting for its prevalence.

Population Attributable RiskTermPAR, Population Excess Risk

The reduction in disease incidence within a population that would result from eliminating a harmful exposure entirely, expressed as an absolute rate.

Population CoverageTermPopulation Entitlement, Entitled Population Share

The proportion of a defined population covered by a health financing or insurance scheme, one dimension of universal health coverage progress.

Population EVPIConceptAggregate EVPI, Whole-Jurisdiction EVPI

The expected value of perfect information calculated for an entire affected patient population over time, rather than for a single patient.

Population HealthTermCommunity Health Status, Group Health Outcomes

The health outcomes of a group of individuals, including their distribution, encompassing healthcare delivery and broader social and environmental determinants.

Population Health ManagementTermPHM, Managed Population Health

An approach focusing on improving outcomes for an entire defined patient population, incorporating proactive outreach, risk stratification, and coordinated care.

Population-Based PaymentTermPopulation Payment Model, Per-Capita Provider Payment, Population Payment

A methodology reimbursing a provider based on the overall health needs and outcomes of a defined population, rather than individual services delivered.

Population-Level ModelTermAggregate-Level Model, Whole-Population Model

A decision-analytic model representing outcomes for an entire population rather than individual patients, often used to capture transmission or budget effects.

Portability DesignTermCoverage Transferability, Plan Portability Rules

Features built into an insurance product or account letting coverage or accumulated funds remain with an individual across employer or plan changes.

Positive ExternalityConceptBeneficial Spillover, External Benefit

A benefit conferred on a third party by an economic activity, not reflected in its market price, leading to underproduction relative to the social optimum.

Positive FeedbackTermReinforcing Loop, Amplifying Feedback

A causal relationship in which a change in one variable triggers effects that reinforce the original change, tending to accelerate the system's trajectory.

Positive Likelihood RatioConceptLR+, Positive LR

A diagnostic test measure expressing how much a positive result increases the odds that a patient truly has the condition tested for.

Positive ListTermReimbursement List, Inclusion List

A list explicitly specifying which medications or services are covered under a health plan, unlike a negative list specifying exclusions.

Positive Predictive ValueConceptPPV, True-Positive Share

The probability that an individual with a positive diagnostic test result truly has the condition being tested for.

Positive RecommendationTermFavourable Recommendation, Recommend-For Decision

A body's formal decision to recommend a technology for funding, based on acceptable cost-effectiveness at the reviewed price.

Post-Acute CareTermPAC, Sub-Acute Care

Healthcare services provided after an acute hospitalisation to support continued recovery, spanning skilled nursing, rehabilitation, and home health settings.

Post-Hoc AnalysisTermPost-Hoc Testing, Unplanned Analysis

A statistical analysis conducted after a trial's data have already been examined, often exploring a hypothesis or subgroup not prespecified.

Post-Marketing CommitmentTermPMC, Voluntary Post-Approval Study

A study a manufacturer voluntarily agrees to conduct after approval, unlike a formally mandated post-marketing requirement, characterising real-world safety or effectiveness.

Post-Marketing RequirementTermPMR, Mandated Post-Approval Study

A study regulators formally mandate a manufacturer conduct after approval, often as a condition of accelerated approval granted on a surrogate endpoint.

Post-Marketing SurveillanceTermPhase IV Surveillance, Post-Approval Monitoring, Post-Market Monitoring, Post-Launch Monitoring, Ongoing Market Watch

The ongoing monitoring of a drug's safety and effectiveness after regulatory approval, capturing information not always evident from pre-approval trials.

Post-Test ProbabilityConceptPost-Test Risk, Updated Diagnostic Probability

The updated probability that a patient has a condition after a diagnostic test result is known, combining pre-test probability with the likelihood ratio.

Posterior DistributionConceptPosterior, Updated Distribution

In Bayesian statistics, the updated probability distribution for a parameter after combining a prior distribution with the likelihood of observed data.

Posterior OddsTermUpdated Odds, Post-Data Odds

The updated odds that a hypothesis is true after incorporating new evidence, found by multiplying prior odds by the likelihood ratio.

Posterior ProbabilityTermPosterior Belief, Updated Probability

The updated probability of a hypothesis after accounting for observed evidence, combining a prior probability with the likelihood of that evidence.