Dictionary

O

OptimisationTermOptimization, Objective Maximisation

In health economics, the selection of the resource allocation or treatment decision that maximises health outcomes or net benefit subject to budget and capacity constraints, applied in decision-analytic modelling and priority setting.

Optimized RecommendationTermOptimised Recommendation, Restricted Positive Recommendation

A decision recommending a technology for funding only within a narrower patient subgroup than its full licensed population, typically the most cost-effective subgroup.

Option ValueTermValue of Optionality, Preservation Value

In health economics, the value people place on preserving the option to use a service or technology in future, even when they do not use it now.

Oral AdministrationTermOral Route, Per Os Administration

A route of drug administration in which medication is taken by mouth and absorbed through the digestive system, generally the most convenient long-term route.

Oral Health EconomicsTermDental Economics, Oral Care Economics

The application of health economic evaluation to dental and oral healthcare, covering prevention, restorative treatment, and periodontal disease management.

Order SetTermPre-Written Order Group, Care Order Bundle

A predefined, standardised group of orders for medications or tests commonly used together for a specific condition, built into an EHR.

Ordinal ScalingConceptOrdinal Measurement, Rank Ordering

A measurement scale property in which values can be ranked but numerical differences do not necessarily reflect equal differences in the underlying quantity.

Organ ResponseTermOrgan-Level Response, Organ-Specific Improvement

A biomarker-based outcome measure indicating improvement in a specific organ's function or structure affected by disease, requiring disease-specific validated criteria.

Organisational EvidenceTermService-Delivery Evidence, System-Impact Evidence

Information addressing how an assessment decision might affect broader operational aspects of a health system, such as staffing or infrastructure needs.

Organisational ReviewTermService Impact Review, Delivery-System Review

An evaluation of the organisational and operational implications of adopting a new technology, examining infrastructure, training, and workflow needs.

Orphan DiseaseTermRare Condition, Rare Disorder

A disease affecting a very small number of people, below a specified population threshold, historically receiving limited treatment development investment.

Orphan DrugTermRare Disease Drug, Orphan Medicine

A treatment developed specifically for a rare disease below a specified population threshold, eligible for special regulatory designation and incentives.

Orphan Drug DesignationTermODD, Special Regulatory Status, Orphan Designation

A regulatory status for a rare disease treatment, giving development incentives such as tax credits, fee waivers, and extended market exclusivity.

Orphan Drug IncentivesTermRare-Disease Incentives, Orphan Development Incentives

The regulatory and financial benefits offered to manufacturers developing rare disease treatments, including trial expense tax credits and extended exclusivity.

Orphan Drug PricingTermOrphan Pricing, Rare-Disease Drug Pricing

The pricing strategies applied to rare disease treatments, frequently priced far higher per patient than common-condition treatments given the smaller patient population.

Orphan Drug ThresholdTermOrphan Threshold, Higher Rare-Disease Threshold

The population size threshold defining a disease as rare or orphan for regulatory designation, varying somewhat across countries and jurisdictions.

Orphan ExclusivityTermOrphan Market Exclusivity, Orphan Drug Exclusivity

A market exclusivity period following orphan drug approval during which regulators generally will not approve a similar competing product for the same rare indication.

Orthogonal DesignConceptOrthogonal Array Design, Uncorrelated Design

An experimental design for a choice experiment in which attribute levels are varied independently, so each attribute's effect on preference can be separated statistically.

Orthogonal RotationConceptUncorrelated-Factor Rotation, Varimax-Type Rotation

A factor analysis technique transforming a solution into a more interpretable structure while constraining the resulting factors to remain uncorrelated.

Orthopaedic EconomicsTermOrthopedic Economics, Orthopaedic Surgery Economics

The application of health economic evaluation to surgical and non-surgical treatment of the musculoskeletal system, covering joint replacement and spine surgery.

OsteoarthritisTermOA, Degenerative Joint Disease

A degenerative joint condition involving progressive cartilage breakdown, commonly affecting weight-bearing joints such as the knee and hip.

Osteoporosis EconomicsTermBone Density Economics, Fragility Fracture Economics

The application of health economic evaluation to osteoporosis, covering screening, preventive medication, and fracture prevention in at-risk populations.

Otological EconomicsTermEar Economics, Otology Economics

The application of health economic evaluation to ear conditions, spanning hearing loss, balance disorders, and chronic ear infections.

Out-of-NetworkTermOON, Out-of-Plan Provider

A designation for providers without a contractual agreement with a specific plan, typically resulting in higher cost-sharing or no coverage.

Out-of-Network ReferralTermOON Referral, External Referral

A referral to a provider without a contractual relationship with the patient's insurance plan, typically resulting in higher cost-sharing or no coverage.

Out-of-Pocket CostConceptOOP Cost, Patient Out-of-Pocket Spending

The amount a patient or household pays directly for health care without third-party reimbursement, including applicable cost sharing and uncovered care.

Out-of-Pocket MaximumTermOOP Maximum, Maximum Out-of-Pocket

The highest total amount an insured person will pay for covered costs within a period, beyond which the plan covers everything further.

Out-of-Pocket ModelTermOOP Health System, Direct-Payment Health System

A financing arrangement in which patients pay directly for care at the point of service, with little or no pooled prepayment to spread risk.

Out-of-Pocket PaymentTermOOP Payment, Direct Patient Payment

A general term for healthcare spending paid directly by a patient, rather than through insurance, covering cost-sharing and uncovered services.

Out-of-Pocket ShareTermOOP Share, OOP Financing Share

The proportion of total healthcare expenditure within a country paid directly by patients, rather than through pooled financing mechanisms.

Out-of-SampleTermHoldout Sample, Test-Set Evaluation

Describing performance calculated using data not used in a model's original construction, giving a more realistic assessment of likely real-world accuracy.

Outbreak CostTermCost of Outbreak, Epidemic Cost

The total economic burden of an infectious disease outbreak, covering direct healthcare costs, public health response spending, and productivity losses.

Outbreak InvestigationTermEpidemic Investigation, Field Epidemiology Investigation

A systematic epidemiological process identifying an outbreak's source, mode of transmission, and scope, typically conducted under time pressure.

Outbreak Response EconomicsTermOutbreak Economics, Epidemic Response Economics

The application of health economic evaluation to resources deployed in outbreak response, including surveillance, contact tracing, and containment measures.

Outcome AssessmentTermOutcomes Measurement, Outcome Evaluation

The measurement and evaluation of health outcomes resulting from care, treated as one of the three linked dimensions of quality alongside structure and process.

Outcome MeasureConceptOutcome Metric, Endpoint Measure

A specified instrument, observation or data rule used to quantify a health, care or resource outcome for a defined population and time point.

Outcome QualityTermOutcome Dimension of Quality, Results Quality

A healthcare quality dimension focused on actual care results, such as survival or functional status, unlike structural or process quality.

Outcome Quality IndicatorTermOutcome Indicator, Results Quality Indicator

A specific, measurable metric assessing actual health results, such as mortality or complications, used to evaluate a provider's clinical performance.

Outcome ReportingTermResults Reporting, Endpoint Reporting

The practice of documenting and disclosing a study's results, ideally consistent with what was originally planned before results were known.

Outcome Reporting BiasTermSelective Outcome Reporting, Outcome Switching

Bias arising when the outcomes reported in a published study are selected based on the direction or significance of their results, not as originally planned.

Outcome Selection HTATermHTA Endpoint Choice, Outcome Prioritisation

The process of determining which clinical, economic, or patient-reported outcomes will be considered relevant within a given assessment.

Outcome StructureTermOutcome Model Structure, Results-Pathway Architecture

The way a decision-analytic model links its outcomes, including how intermediate clinical events translate into measures such as QALYs and total cost.

Outcome-Based BudgetTermResults-Based Budget, Outcome-Linked Budget

A budgeting approach that allocates funds according to expected or achieved health outcomes rather than historical spending or input costs.

Outcome-Based PricingTermPerformance-Based Pricing, Pay-for-Performance Pricing

A pricing arrangement in which some or all payment for a treatment depends on it achieving predefined clinical outcomes in actual practice.

Outcome-Based RebateTermOutcomes-Based Rebate, Results-Linked Rebate

A manufacturer rebate paid or withheld depending on whether a treatment achieves a predefined clinical outcome for the patients who received it.

Outcomes-Based ContractTermValue-Based Contract, Results-Based Agreement

A formal agreement in which some or all of a treatment's payment is contingent on it achieving predefined clinical outcomes in practice.

Outcomes-Based PaymentTermPay-for-Outcomes, Results-Based Payment

A reimbursement arrangement in which some or all of a manufacturer's payment depends on the treatment achieving a predefined clinical outcome in actual practice.

Outer LoopTermParameter Loop, First-Level Loop

The portion of a nested simulation sampling parameter values that remain fixed while a complete inner loop simulation runs beneath it.

OutlierTermExtreme Value, Anomalous Observation

An observation differing markedly from other values in a dataset, either from genuine unusual variation or a measurement or entry error.

Outlier IdentificationTermOutlier Detection, Anomaly Detection

The process of identifying data points, cases, or providers whose performance substantially deviates from an expected pattern, flagging further investigation.