Dictionary

T

Tiered PricingTermPrice Tiering, Graduated Pricing

A pricing strategy charging different prices for the same product across markets, typically calibrated to differences in ability to pay.

Time DependencyConceptTime-Dependence, Temporal Dependence

The property of a risk, effect, cost, utility or other model input changing according to a specified time scale, such as attained age or time since an event.

Time HorizonConceptAnalytic Horizon, Evaluation Period

The span of time over which an economic evaluation captures relevant differences in costs and outcomes among the options being compared.

Time Horizon ChoiceTermHorizon Choice, Analytic Horizon Decision

The methodological decision on how long a model should simulate costs and outcomes, informed by disease natural history and treatment effect duration.

Time Horizon Selection HTATermHTA Time Horizon, Lifetime Horizon Selection

The methodological decision on how long a cost-effectiveness analysis should simulate costs and outcomes, often requiring a full lifetime horizon for chronic conditions.

Time on TreatmentTermToT, Duration on Therapy

The duration a patient continues receiving a specific therapy before discontinuation, whether from progression, intolerable effects, or achieving the treatment goal.

Time PreferenceConceptTemporal Discounting, Impatience Parameter

Time preference is the preference for benefits sooner and costs later; in health economics it is one reason future costs and QALYs are discounted.

Time Series DataTermTemporal Data, Time-Ordered Data

Data consisting of repeated measurements of the same variable collected sequentially over time, such as monthly disease incidence rates.

Time Series DesignTermTime Series Study, Serial Measurement Design

A study design examining a sequence of observations on one population collected repeatedly over time, often to assess a policy's impact before and after.

Time StepTermSimulation Step, Iteration Interval

The fixed interval of time by which a discrete-time model, such as a Markov model, advances with each calculation.

Time StructureTermTemporal Structure, Model Timing Framework

The way a model represents the passage of time, whether in fixed discrete cycles, as in a Markov model, or continuously.

Time to MarketTermSpeed to Market, Launch Timeline

The total elapsed time from a drug candidate's discovery to regulatory approval and market availability, often spanning a decade or more.

Time to ResponseTermResponse Time, Time until Response

The interval between the start of treatment and the point a patient meets a defined responder threshold on a relevant outcome measure.

Time Trade-OffConceptTTO, Life-Year Trade-Off

A health state valuation method asking how many years in full health a respondent would consider equal to a longer period in an impaired state.

Time Value of MoneyConceptTVM, Present Value Principle

The principle that a given sum of money is worth more today than the same sum received in the future.

Time with SymptomsTermSymptomatic Time, Time in Symptomatic State

A phase within the Q-TWiST framework representing the period during which a patient experiences symptoms of disease progression or treatment toxicity.

Time Without Symptoms of ProgressionConceptTWiST, Symptom-Free Progression-Free Time

A phase within the Q-TWiST framework covering the period free of significant treatment toxicity or disease progression symptoms, typically weighted highest.

Time-Driven Activity-Based CostingConceptTDABC, Time-Driven ABC

A costing method estimating a service's cost by multiplying the capacity cost rate of resources involved by the time required to complete each activity.

Time-Fixed CovariateTermBaseline Covariate, Time-Invariant Covariate

A patient characteristic in a survival model measured once and assumed constant throughout follow-up, such as baseline age or sex.

Time-Homogeneous ModelConceptTime-Constant Model, Stationary Markov Model

A Markov model in which transition probabilities remain constant throughout the entire modelled time horizon, regardless of how many cycles have passed.

Time-Inhomogeneous ModelConceptTime-Varying Markov Model, Non-Stationary Model

A Markov model in which transition probabilities are allowed to vary over the time horizon, such as mortality risk rising with age.

Time-to-EventConceptEvent-Time Outcome, Event-History Outcome

Outcome data recording the duration until a specific event of interest occurs, such as disease progression or death, possibly censored.

Time-Varying CovariateConceptTime-Dependent Covariate, Updating Covariate

A patient characteristic in a survival model allowed to change value over follow-up, such as a repeatedly measured biomarker.

Time-Varying HazardConceptTime-Dependent Hazard, Non-Constant Hazard

A hazard rate that changes in magnitude over follow-up, unlike a constant hazard that stays the same at every point.

Timely AccessTermPrompt Access, Timeliness of Care

A healthcare access dimension concerning whether patients can obtain needed care within a clinically appropriate timeframe, including wait times.

Tipping Point AnalysisTermTipping-Point Method, Switch-Point Analysis

A missing data sensitivity technique searching for the specific departure from a standard assumption that would be needed to overturn a study's conclusion.

TitrationTermDose Adjustment, Dose Ramping

The process of gradually adjusting a medication's dose, usually starting low and increasing, to balance therapeutic effect against tolerability.

TLVTermDental and Pharmaceutical Benefits Agency, Swedish Benefits Agency

The Swedish Dental and Pharmaceutical Benefits Agency, determining which pharmaceuticals and dental services are subsidised based on cost-effectiveness assessment.

Tobacco Control EconomicsTermEconomics of Tobacco Control, Smoking Control Economics

The application of health economic evaluation to population-level tobacco policies, including taxation, advertising restrictions, and public smoking bans.

Tobacco PolicyTermTobacco Control Policy, Anti-Smoking Policy

Government policy aimed at reducing tobacco use, covering taxation, advertising restrictions, public smoking bans, and cessation programme funding.

Tobacco Use PrevalenceTermSmoking Prevalence, Tobacco Prevalence

A measure of the proportion of a population currently using tobacco products, a leading modifiable chronic disease risk factor.

ToleranceTermDrug Habituation, Reduced Drug Response

A regression diagnostic, one minus a predictor's coefficient of determination against all other predictors, detecting multicollinearity, lower values meaning more collinearity.

Tolerance IntervalConceptCoverage Interval, Population Coverage Bound

An interval calculated to contain a specified proportion of an entire population's values with a given confidence, unlike a confidence or prediction interval.

Toll GoodsTermExcludable Non-Rival Goods, Toll Good

Goods that are excludable but non-rivalrous within capacity, allowing a charge for access while extra users add little cost until congestion is reached.

Top-Down Cost-of-IllnessTermPrevalence-Based Cost-of-Illness, Aggregate Cost-of-Illness

A cost-of-illness study estimating disease-specific cost by apportioning a share of national or aggregate expenditure statistics to a particular condition.

Top-Down CostingConceptMacro-Costing, Top-Level Costing

A costing approach that starts with aggregate costs and allocates them to services, activities or patients using documented shares and output counts.

Topic IdentificationTermTopic Scanning, Candidate Identification

The initial process by which an assessment body identifies technologies or questions that may warrant formal assessment, from various sources.

Topic NominationTermTopic Proposal, Assessment Nomination

A formal proposal submitted suggesting that a specific technology or clinical question be selected for formal assessment.

Topic PrioritisationTermTopic Ranking, Assessment Prioritisation

The process of ranking candidate assessment topics by criteria such as clinical importance and budget impact, given limited assessment capacity.

Topic SelectionTermAssessment Selection, Topic Decision

The formal decision on which candidate technologies or questions will proceed to a full assessment, following identification and prioritisation.

Topical AdministrationTermTopical Application, Local Administration

A route of drug administration applying medication directly to the skin or another surface for local effect, common in dermatological conditions.

Tornado DiagramConceptTornado Plot, Tornado Chart

A horizontal bar chart displaying one-way sensitivity analysis results, bars ranked from largest to smallest range, resembling a tornado shape.

Total CostTermAggregate Cost, Total Expenditure

The sum of all costs, fixed and variable, incurred in producing a given level of output.

Total Cost of CareTermTCOC, Total Care Cost

A comprehensive measure of all healthcare spending associated with a defined population over a period, across all settings and providers.

Total Effect IndexConceptTotal Sobol Index, Total-Order Index

A variance-based sensitivity measure quantifying an input's total contribution to output variance, including its individual effect and all interactions with other inputs.

Total Quality ManagementTermTQM, Organisation-Wide Quality Management

A comprehensive organisational philosophy emphasising continuous improvement, customer focus, and employee engagement in identifying and addressing quality problems.

Toxicology StudiesTermToxicology Testing, Preclinical Toxicology

Research, typically in laboratory and animal models, characterising a drug candidate's potential harmful effects at various doses before human testing.

Toxoplasmosis EconomicsTermEconomics of Toxoplasmosis, Toxoplasma Economics

The application of health economic evaluation to toxoplasmosis, a parasitic infection posing particular risks to immunocompromised patients and fetal development.

Trace ValidationTermTrace Checking, Patient-Path Checking

The review of a Markov model's cohort trace, the proportion of a modelled population in each health state over time, for clinical plausibility.

Traceable CostTermDirectly Attributable Cost, Assignable Cost

A cost that can be directly attributed to a particular department, product, or service line without relying on an allocation method.