Tariff
The specific set of utility weights, derived from a population valuation study, used to convert health status instrument responses into a single score.
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.
Tarone-Ware Test
A test comparing survival distributions using a weighting scheme between the log-rank and Peto tests, a compromise depending on when treatment differences emerge.
Tau-Squared
A statistical parameter representing the estimated variance of the true treatment effect across studies in a random effects meta-analysis.
Taylor Series Expansion
A mathematical technique approximating a complex function using a polynomial series based on its derivatives at a single point, underlying the delta method.
Taylor Series Method
The practical application of a Taylor series expansion to derive an approximate variance formula for a function of random variables.
Technical Efficiency
A condition in which the maximum possible output is produced from given inputs, without regard to whether those inputs serve their highest-value use.
Test Statistic
A single numerical value calculated from sample data during a hypothesis test, used to judge whether to reject the null hypothesis.
Test-Retest Reliability
The degree of agreement between scores from the same instrument given to the same people on two separate occasions, when no real change is expected.
Theil Index Health
An information theory based inequality measure applied to a health outcome's distribution, decomposable into inequality within and between population subgroups.
Therapeutic Index
A drug's safety margin, calculated as the ratio between the dose that produces toxicity and the dose producing the desired effect.
Threshold Analysis
A sensitivity analysis technique identifying the value at which an input parameter would need to be set for a model's conclusion to change.
Threshold Approach
A decision-making method that classifies an intervention as cost-effective or not based on whether its ICER falls below a predetermined threshold.
Throughput
A measure of the rate at which patients or units move through a healthcare process over a given period.
Time Complexity
A measure of how the execution time of an algorithm grows as the size of the input increases.
Time Dependency
A situation where the probability of a health state transition depends on elapsed time, such as time since diagnosis, rather than staying constant.
Time Horizon
The span of time over which an economic evaluation captures relevant differences in costs and outcomes among the options being compared.
Time Preference
The general tendency to prefer a benefit sooner rather than later, or a cost later rather than sooner, underlying the case for discounting.
Time 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 Money
The principle that a given sum of money is worth more today than the same sum received in the future.
Time Without Symptoms of Progression
A phase within the Q-TWiST framework covering the period free of significant treatment toxicity or disease progression symptoms, typically weighted highest.