Dictionary
The Dictionary provides concise definitions of health economics terms, arranged alphabetically for quick reference. Use it to understand unfamiliar terminology or confirm the meaning of a specific term.
Q
- Quality-Adjusted Expectancy
- A summary population health measure expressing expected remaining years of life weighted by health-related quality of life during those years.
- Queuing Model
- A mathematical model describing how entities wait in line for limited servers, used to analyse average waiting time and server utilisation.
R
- Random Error
- Variation in results attributable to chance alone, from the statistical variability of sampling, unlike systematic error, which reflects a consistent directional bias.
- Random Search
- An optimisation technique evaluating an objective function at randomly sampled points in the parameter space rather than a systematic grid.
- Rapid Review
- An abbreviated systematic review conducted under time constraints, streamlining literature searching or quality assessment to produce timely evidence.
- Rapid Review HTA
- An abbreviated systematic review conducted under time constraints, streamlining steps such as searching or quality assessment to support an urgent decision.
- Rate-to-Probability Conversion
- The mathematical transformation converting a continuous-time hazard rate into the probability of an event occurring within a discrete time interval.
- Reporting Bias
- A broad category of bias arising when selective reporting of research findings, at study or outcome level, systematically distorts available evidence.
- Residual Analysis
- A statistical technique examining the differences between a model's predicted values and observed data, checking for systematic patterns left unexplained.
- Resource Constraint
- A limit on the total resources, such as budget, staff, or facilities, available to an organisation, within which competing demands must be prioritised.
- Response Surface
- A fitted mathematical approximation describing how a model's output varies with its inputs, built from limited runs and used to predict untested combinations.
- Review Date
- The scheduled point at which previously published guidance is planned to be formally reassessed to determine whether it remains current.
- Risk Assessment
- A systematic process identifying and evaluating compliance vulnerabilities within an organisation, used to prioritise monitoring and auditing efforts.
- Risk of Bias
- The degree to which a study's design, conduct, or analysis may have introduced systematic errors distorting its findings from the truth.
- Robust Standard Error
- An estimate of a regression coefficient's statistical uncertainty that remains valid even when standard modelling assumptions, such as constant error variance, are violated.
- Root Cause Analysis
- A systematic process investigating a serious adverse event to identify its fundamental, underlying causes, rather than only surface-level circumstances.
- Royston-Parmar Model
- A class of flexible parametric survival models using restricted cubic splines to represent a transformed survival or hazard function while remaining fully parametric.
S
- Safety
- The degree to which an intervention avoids causing unintended harm, assessed through systematic monitoring and reporting of adverse events.
- Sandwich Estimator
- A method calculating an estimator's variance that remains valid even when standard model assumptions are violated, forming the basis of robust standard errors.
- Screening ProgrammeScreening Program
- An organised public health initiative systematically testing an eligible population for early disease signs, before symptoms would otherwise prompt care-seeking.
- Selection Bias
- Bias arising when the individuals included in a study differ systematically from the broader population of interest, in ways linked to exposure and outcome.
- Sequence Effect
- In a crossover trial, a systematic difference in outcomes attributable to the order in which treatments were given, distinct from a carryover effect.
- Simplex Method
- An optimisation algorithm that solves linear programming problems by moving systematically between feasible solutions until the optimum is found.
- Small Study Effects
- A pattern in meta-analysis where smaller studies tend to report systematically larger treatment effects than larger studies, possibly reflecting publication bias.
- Social Welfare Function
- A mathematical representation of how individual wellbeing combines into overall social welfare, embodying explicit judgements about equality versus total welfare.
- Stakeholder Analysis
- A systematic process identifying individuals and groups affected by or interested in a proposed policy, assessing their likely positions and influence.
- Steady State
- A pharmacokinetic condition where a drug's concentration remains stable because the rate of administration equals the rate of elimination.
- Study Selection
- The process of applying predefined inclusion and exclusion criteria to identified studies, determining which are included in a systematic review.
- Supply-Side Control
- Cost containment strategies targeting provider behaviour directly, such as utilisation review, unlike demand-side controls targeting patient incentives.
- Surge Capacity Cost
- The expense of maintaining a health system's ability to rapidly expand service capacity in response to a sudden demand increase.
- Sustainability Criterion
- A standard judging whether continued funding for a technology is likely to remain financially viable long term given future resource constraints.
- Sustained Response
- A treatment response that remains present over a defined, extended follow-up period, rather than being observed only at a single assessment point.
- Symptom Assessment
- The systematic process of measuring the presence, frequency, and severity of disease-related symptoms, typically using standardised, validated instruments.
T
- 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.
- Technology Surveillance
- The ongoing, systematic monitoring of developments within a specific technology area, tracking new evidence, competitors, and evolving clinical practice.
- Testing
- The general process of systematically exercising a model with various inputs and scenarios to detect errors and confirm expected behaviour.
- Threshold Analysis Method
- The systematic approach for identifying the critical value of an uncertain parameter at which a model's decision conclusion would switch to another option.
- Time-Homogeneous Model
- A Markov model in which transition probabilities remain constant throughout the entire modelled time horizon, regardless of how many cycles have passed.
- Toxicology Testing
- The systematic laboratory and animal-based evaluation of a drug candidate's potential to cause harm, establishing an adequate safety margin before human trials.
- Trade-Off Analysis
- A systematic examination of how competing objectives, such as cost and health benefit, are balanced against one another in a given decision.
- Treatment Guideline
- A formal document providing evidence-based recommendations for managing a specific condition, developed by an expert panel following systematic review.
- Truncation
- A situation in survival or longitudinal analysis where certain observations are systematically excluded based on a variable's value, such as required registration.
- Truncation Error
- The error introduced by approximating a mathematical process using a finite number of terms or steps.
- Two-Way Sensitivity
- A sensitivity analysis in which exactly two parameters vary simultaneously across their ranges while all others remain at base case values.
U
- Umbrella Review
- A systematic review summarising evidence from multiple existing systematic reviews addressing related questions, rather than synthesising individual primary studies.
- Uncertainty Assessment
- A systematic evaluation of how confident decision-makers should be in a model's results, given parameter, structural, and methodological uncertainty.
- Utilisation TrendUtilization Trend
- The pattern of change in healthcare service use over time, identifying emerging demand shifts or effects of policy changes.
- Utility Function
- A mathematical representation of preferences that assigns a numerical value to each possible outcome, so higher-utility outcomes are preferred.
V
- Value Framework
- A structured tool for systematically assessing a technology's overall value, encompassing considerations beyond a single cost-effectiveness ratio, such as toxicity.
- Value of Statistical Life YearVSLY
- An adaptation of the value of statistical life expressed per life-year rather than per life, adjusted for age and remaining life expectancy.