Glossary

A posteriori (literally: ‘from the latter') hypotheses are formed after observing data or empirical evidence, as opposed to being pre-defined. These hypotheses are developed through inductive reasoning and are used

A priori (literally: ‘from the former’) hypotheses are those based on prior research, assumed principles, and deductive reasoning. These hypotheses are developed before a new study begins, guiding the design

The absolute risk of an outcome associated with exposure to an agent (e.g. a therapy) is of less value than the difference in absolute risk between exposed and unexposed groups.

An asynchronous online focus group (AOFG) is a qualitative research method. A group of participants, such as patients, caregivers, or healthcare professionals, engage in a moderated discussion on a specific

A base case analysis usually refers to the results of an economic model using the most likely or preferred set of assumptions and input values. It establishes a baseline for

Bayesian analysis is a statistical inference approach where data are collected to refine the estimate of a particular quantity (often a probability) that may be used for decision making. This

Bias refers to a systematic error in a study, skewing results in either direction. 'Systematic error' means that the study will consistently reproduce an inaccurate result, regardless of how many

Bootstrapping is a non-parametric technique used to estimate the distribution of an important statistic, such as an incremental cost-effectiveness ratio (ICER), from a population sample, such as a clinical trial. Random samples (of

Budget impact analyses are used to estimate the likely change in expenditure for a specific budget holder resulting from a decision to fund a new healthcare intervention or some other

Burden-of-illness reviews are conducted to comprehensively understand the impact of a particular disease. By reviewing the literature, these studies aim to quantify the disease burden (such as the incidence, prevalence,

The Cancer Drugs Fund (CDF) in England was established in 2011 as a response to public pressure to fund access to cancer drugs that might not be reimbursed under standard

A case-control study is an observational study that compares two groups of participants: individuals with a specific outcome or condition (cases) and individuals without it (controls). This study design involves

A case-series is a retrospective observational study that examines participants on the basis of outcome alone (regardless of treatment received) or on the basis of outcome and a specific treatment.

A citation index is a specialised bibliographic database that offers citation analysis features, going beyond simply listing publications. A key functionality is the ability to explore the citation network of

A clinical equivalence study is a comparative study that aims to demonstrate that the difference in outcomes between two or more interventions is so small that it is considered clinically

A clinical outcome assessment (COA) is a measure that captures how a patient feels, functions, or survives. COAs are categorised into several types based on the reporter or the method

A clinical trial is a research investigation conducted in a clinical setting, designed to generate data on the efficacy and/or safety of a drug, device, treatment, or other healthcare intervention.Clinical

Now called 'Cochrane', this collaboration was founded in 1993 following Archie Cochrane's advocacy for up-to-date, systematic reviews of randomised controlled trials (RCTs). Its aim is to systematically organise medical research

Cognitive debriefing is a structured interview technique employed during the development of patient-reported outcomes (PROs). It involves interviewing members of the intended patient population to ensure all relevant concepts are

Cognitive interviewing is a method employed in the development and refinement of patient-reported outcome measures (PROMs) to elicit the patient's perspective on specific domains or individual items within the PROM.

A cohort model simulates the experience of a group (cohort) of patients receiving (or not receiving) a new therapy. Instead of tracking the the response of individuals, the model estimates

A cohort study is an observational study in which groups of participants are selected based on whether they have been (or will be) exposed to a specific factor. These cohorts

Concept elicitation is a term used in outcomes research to describe the process by which concepts that are important to patients (i.e. symptoms and impacts) emerge spontaneously through the use

A confidence interval is a measure of uncertainty in the estimated value due to sample error, quantifying the imprecision. It provides an estimated range of values around a measured value

Conjoint analysis is an analytical technique employed in discrete choice experiments. In healthcare, it is used to understand the preferences of participants (patients, payers, commissioners) for different characteristics (attributes) of

Construct validity refers to the evidence that supports pre-defined hypotheses about the expected relationships between a patient-reported outcome measure (PROM) and other measures assessing similar or dissimilar constructs. It encompasses

Content validity refers to the evidence that both patients and experts involved in developing a patient-reported outcome measure (PROM) deemed its content relevant and comprehensive to the specific concept, population,

While everyday understanding of 'cost' often equates to monetary price, in economic evaluation, cost is more accurately defined as the (monetary) value of anything that has to be sacrificed to

Cost-of-illness (COI) analysis provides a summary of the total economic burden of a specific disease on society. This encompasses direct costs, such as healthcare system expenditures for diagnosis, treatment, disease

Cost-benefit analysis in healthcare evaluation is a comparative method that values both the costs of interventions and their resulting benefits (including health outcomes) in monetary terms. This allows for the

Cost-comparison analysis A cost-comparison analysis is a method used to compare the total costs of different interventions (including the costs of managing any related consequences) that are known or assumed

The cost-effectiveness acceptability curve (CEAC) is a graph that summarises the impact of uncertainty on the result of an economic evaluation, often presented as an incremental cost-effectiveness ratio in relation

The cost-effectiveness acceptability frontier (CEAF) is a graph that summarises the uncertainty surrounding the cost effectiveness of interventions compared in a model, illustrating which intervention is most likely to be

A cost-effectiveness analysis (CEA) is a type of economic evaluation that evaluates the effectiveness of two or more interventions relative to their cost. These evaluations can be used by decision-makers

The cost-effectiveness frontier is the line that connects successive points on a cost-effectiveness plane, where each point represents the cost and effect of different treatment alternatives. The gradient of a

The cost-effectiveness plane is a two-dimensional graph used in healthcare evaluation to visually compare the differences in costs and health outcomes between treatment alternatives. Health outcomes (effects) are typically plotted

The cost-effectiveness threshold is the maximum amount a decision maker is prepared to pay for a unit of health outcome, such as a quality-adjusted life year (QALY). When the cost-effectiveness

Cost-minimisation analysis is a now outdated term, replaced by the term cost-comparison analysis.

Cost-utility analysis (CUA) is a specific type of cost-effectiveness analysis where the outcome is measured in terms of preference-based valuations of health, most commonly quality-adjusted life years (QALYs). CUA compares

Coverage with evidence development (CED) is a type of managed entry agreement for new health technologies, especially pharmaceuticals. Under this model, a technology is reimbursed ('covered') for a limited period,

Credible intervals are used in Bayesian statistics to quantify the uncertainty about an unobserved parameter (such as an effect estimate in a network meta-analysis). A credible interval represents the range

Criterion validity assesses how well the scores from a patient-reported outcome measure (PROM) align with a recognised "gold standard" measure of the same or a closely related construct. There are

Critical appraisal is the systematic process of evaluating research (e.g. clinical trial, meta-analysis, cost-effectiveness analysis) to assess the validity and appropriate application of its methods, the accuracy of its reported

A cross-sectional study is an observational study in which a patient's exposure (or treatment) and outcome are measured at the same time.

Data extraction is the process of identifying and retrieving relevant information and data from various sources. In systematic reviews, these data sources can include both published and grey literature. A

A database search is a structured query formulated and executed within one or more literature databases to identify studies relevant to a specific information need. Effective searching requires adapting the

A decision tree is an analytical model commonly used in economic evaluation, in which distinct branches represent the potential sequence of events and outcomes for a patient or patient cohort.

The Delphi method is a structured, iterative technique for soliciting and refining expert opinion, originally developed for forecasting purposes. In health technology assessment (HTA) and economic evaluation, this method has

Deterministic sensitivity analysis (DSA) is a method used to investigate the sensitivity of the results from a model-based analysis to variations in specific input parameters: one or more parameters are

A diagnostic test accuracy review is a specialised systematic review that focuses on identifying, summarising, and synthesising evidence on the performance (accuracy) of a specific diagnostic test. It evaluates the

The Diagnostics Assessment Programme (DAP) is run by the National Institute for Health and Care Excellence (NICE) in the UK. Its purpose is to evaluate the clinical effectiveness and cost

The Digital Technology Assessment Criteria (DTAC) are a set of standards and guidelines used to evaluate the safety, effectiveness, and quality of digital health technologies, ensuring they meet a minimum

The disability-adjusted life year (DALY) is a generic measure of health effect that can be used in cost-effectiveness analysis as an alternative to the quality-adjusted life year (QALY). Originally developed by

In economic evaluations, discounting is the practice of reducing the monetary value of future costs and the health value of future outcomes to reflect their lower present value. This adjustment

A discrete choice experiment (DCE) is a quantitative method used in healthcare to elicit preferences without directly asking participants (e.g. patients, payers) to state their preferred options. Participants are presented

Discrete event simulation (DES) is a computer-modelling technique used in the economic evaluation of health interventions. It works by simulating the experience of individual patients over time, tracking events and

A disease model is a simplified mathematical representation of the natural history and progression of a disease over time within a patient cohort. In health technology assessment, these models are

Distributional cost-effectiveness analysis (DCEA) is an extension of a standard cost-effectiveness analysis (CEA) that assesses not only a health intervention's overall impact on health and costs, but also how these

In statistics, distributions describe the spread of values for a particular characteristic measured in a population. For example, while we may know the mean age of a population, most individuals

Disutility represents a decrement in utility (valued quality of life) caused by a specific symptom or complication. These values are often expressed negatively to reflect the impact of the symptom

A dominant treatment option is one that is both less costly and yields better health outcomes compared with its comparator. In this scenario, the dominant option is preferred - regardless

The EuroQol Five Dimension (EQ-5D) questionnaire is a widely used generic measure of health-related quality of life, frequently employed in clinical trials and prospective studies. It consists of 5 questions,

Historically, health technology assessment (HTA) decision making for health technologies in the EU has been made at a national level, with limited cooperation between countries. The EU HTA Regulation (HTAR;

Early economic models are simplified analytical tools that explore the potential cost effectiveness of treatment alternatives under various circumstances, including future scenarios. They are most commonly used for understanding the

Early Value Assessment (EVA) is a rapid assessment process used by NICE for new and promising medical technologies, including digital products, diagnostics, and devices. This programme is designed to evaluate

Healthcare economic evaluation is a comparative analytical process used to inform choices about allocating resources to healthcare interventions. It examines both the costs and the health effects (and their future

Economic modelling in healthcare involves developing a simplified mathematical representation (model) of real-world processes to support decision making, particularly in health technology assessment. It synthesises diverse clinical, epidemiological and economic

The economically justifiable price (EJP) represents the maximum price at which a healthcare intervention would still be considered an efficient use of limited healthcare resources. It is often estimated as

Effect size is a statistical measure that quantifies the strength of the relationship between two variables on a numeric scale. This metric is used in statistical testing of the null

Effectiveness refers to the ability of an intervention (e.g. drug, device, treatment, test, or pathway) to achieve its desired health outcome(s) in a typical, real-world clinical scenario and within the

Efficacy is the benefit achieved by an intervention under ideal conditions, typically within a randomised controlled trial (RCT). These 'ideal conditions' refer to experimental controlled settings where contextual factors (e.g.

In health economics, efficiency refers to either maximising health benefits from available resources or achieving a specific health benefit in a way that minimises costs or resources. It encompasses two

Equity in health refers to the fairness in the distribution of health outcomes across individuals, and by extension, may also refer to the fair distribution of healthcare resources (e.g. expenditure,

The NICE Evidence Standards Framework (ESF) describes the standards that digital health technology (DHT) evidence should meet, in order to demonstrate its value in the UK health and social care

Evidence-based medicine is a systematic approach to clinical decision making that integrates the current best evidence with clinical knowledge and experience. Coined in the late 1980s by a group from

The expected value of partial perfect information (EVPPI) represents the maximum price a healthcare decision maker would (in theory) be willing to spend to gain perfect information for at least

The expected value of perfect information (EVPI) represents the price that a healthcare decision maker would be willing to pay to have perfect information regarding all parameters that influence the

The expected value of sample information (EVSI) estimates the value of collecting additional sample information. Typically, additional research reduces (rather than eliminates) uncertainty, meaning that perfect information is not available. Therefore,

See type 1 and type 2 errors.

A feasibility assessment is conducted to identify whether it is appropriate to combine data from multiple trials for the purpose of indirect treatment comparison. This is qualitative assessment focused on:

In Markov-type economic models, it is generally recommended that a half-cycle correction is incorporated in the analysis. This adjustment accounts for the fact that health events and transitions between health

Hand searching refers to retrieval methods that rely more heavily on the comprehensive browsing and scalling of all content in a specific journal issue, supplement, conference or website. This method

Health economics is a specialised field of economics that focuses on the "analysis and understanding of efficiency, effectiveness, values, and behaviors involved in the production and consumption of health and

Health Economics and Outcomes Research (HEOR) is a widely adopted label for teams within life-science companies that generate evidence of value for health technologies and interventions. While 'health economics' mostly

Health technology assessment (HTA) is a multidisciplinary evaluation of the clinical effectiveness, cost effectiveness, budget impact, and/or the broader social and ethical impacts of a health technology on patient lives

Health-related quality of life (HRQoL) is a multi-dimensional concept that measures an individual's overall wellbeing as it is affected by their health state. Unlike a purely clinical measure (such as

Highly specialised technologies (HST) are interventions that address very rare conditions. In the UK, these technologies are assessed by a dedicated, specialist HST committee, who employ a broader assessment framework

Horizon scanning is a process used to identify new and emerging health technologies, treatments, and interventions that are likely to become available in the near future. This proactive research helps

A statistical hypothesis test is a method of statistical inference used to compare two datasets obtained through sampling, or to compare a dataset against a synthetic dataset derived from an

Incidence quantifies the number of new cases of a disease or events occurring within a specified time period (often one year) within a defined population who are at risk of

The incremental cost-effectiveness ratio (ICER) is a summary measure that represents the economic value of a healthcare intervention when compared with an alternative (comparator). It is usually the main output

An indirect treatment comparison is a method of deriving a comparative estimate between two treatments (treatment A and treatment B) which are not directly compared in head to head trials

The Innovative Medicines Fund (IMF) was designed based on the Cancer Drugs Fund (CDF) to expand managed access to non-cancer medicines. The IMF provides routes to faster patient access while

Intention-to-treat (ITT) analysis refers to analysis based on the initial treatment assignment, not on the treatment eventually received. This type of analysis, now widely accepted as the standard for analysing

Internal consistency is a measure of reliability that assesses the interrelatedness among items within a multi-item measure or tool, such as a patient-reported outcome measure (PROM). It evaluates whether multiple

Item response models may refer either to item-response theory (IRT) or Rasch models. Although not synonymous, both forms of model are measurement or psychometric methods that can be applied to

Joint Clinical Assessment (JCA) is a centralised process under the EU HTA Regulation where a comparative analysis of the clinical evidence for a new health technology is compiled at the

Joint Scientific Consultation (JSC) is a voluntary process that allows health technology developers to obtain early, coordinated advice from EU HTA bodies on their clinical development plans. This consultation aims

Late-stage assessment (LSA) forms part of NICE's lifecycle approach to technology evaluation. LSA aims to assess technologies that are in widespread or established use in the NHS to support procurement

Lead time bias is a form of systematic error that can arise in diagnostic studies. It refers to the apparent increase in survival time observed among individuals who are diagnosed

A literature review is a search and evaluation of available published studies in a chosen topic area. Occasionally, ‘grey’ literature may be included (e.g. unpublished reports, newsfeeds, websites). In economic

A managed access agreement (MAA) is a type of conditional reimbursement arrangement. These agreements, co-ordinated by the National Institute for Health and Care Excellence (NICE), allow a new healthcare technology

Market access refers to the process of ensuring that treatments (e.g. medicines, medical devices) that have been granted marketing authorisation from regulatory authorities are available (reimbursed, funded) to all patients

A marketing authorisation (MA) is a legal licence that a pharmaceutical developer must obtain from a national or regional regulatory body before it can sell and distribute a medicinal product.

A Markov model is a type of analytical framework commonly used in health economic evaluations to simulate a patient cohort's journey through a disease over time. The model represents all

Matching-adjusted indirect comparison (MAIC) is a method used to compare treatments from different clinical trials when no direct head-to-head evidence exists. It uses individual patient data from one trial and

Meta-analysis is a way of combining results from multiple studies to get a single overall estimate of an effect. It is used when studies look at the same outcome in

Micro-simulation is a form of economic modelling where modelled individuals are passed through the model one by one, their results are stored, and then the experience of a cohort is

When assessing the clinical utility of therapies intended to improve subjective outcomes, the amount of improvement that is important to patients must be determined. The smallest benefit of value to

Missing values occur when no data value is stored for a variable of interest in a study observation. In most study datasets, there are missing values; the amount and type

A mixed treatment comparison (MTC) is a statistical method that uses both direct evidence (from trials directly comparing the interventions of interest) and indirect evidence (from trials comparing each intervention

Monte-Carlo simulation is a form of modelling used in many areas of science where model inputs are drawn from distributions and are not treated as fixed values. Key elements of

Multi-criteria decision analysis (MCDA) is a domain of operational research used in healthcare decision making. The technique recognises that decision makers use multiple and disparate criteria when making decisions (e.g.

Multi-way sensitivity analysis is a modelling technique used to investigate the simultaneous impact of uncertainty in multiple model parameters on a model's output. It addresses the fact that the output

A multiple technology appraisal (MTA) is an appraisal undertaken by NICE that compares one or more technologies used in one or more indications of interest. The evidence assessment is undertaken by

When individuals at risk of a condition are administered a diagnostic or screening test for a condition of interest, the negative predictive value (NPV) is the proportion of those who

Net health benefit (NHB) is a summary statistic that represents the impact of introducing a new intervention on population health. Net health benefit assumes that ‘lost health’ can be estimated

Net monetary benefit (NMB) is a summary statistic that represents the value of an intervention in monetary terms when a willingness-to-pay threshold for a unit of benefit (e.g. a measure of health

A network meta-analysis (NMA) is a statistical method using both direct and indirect evidence (conventionally from randomised controlled trials) to estimate the comparative efficacy and/or safety of a number of

A non-inferiority study describes a study where the aim is to show that the effectiveness of one technology is not inferior to a comparator technology by a clinically important amount.

Non-parametric refers to a class of statistical methods that use no or few assumptions about the distribution of characteristic(s) in the underlying population from which the data were drawn. Common

The number needed to treat (NNT) is a measure of the effectiveness of a healthcare intervention. It represents the average number of patients who need to receive a specific treatment

An odds ratio (OR) is a measure of the proportional excess risk of an event in a population compared with the risk in another population. When the populations are defined

The opportunity cost of an intervention is the cost that is foregone as a consequence of adopting a new intervention. In a fixed budget healthcare system where increased costs will

An orphan disease, also known as a rare disease, is a condition that affects a very small percentage of the population. While there is no single, universally accepted definition, in

Outcomes research is a broad field of study with a primary focus of assessing the effectiveness of health interventions and services by measuring their impact on health outcomes. Examples in

A p value is the probability of observing results at least as extreme as those reported in a study, assuming that the null hypothesis is true (usually ‘no difference’). Essentially, this is

PICO is a framework that provides a structured approach for defining the eligibility criteria of a systematic review and for developing a targeted search strategy. It breaks down the research

Parametric refers to a class of statistical methods that use specific assumptions about the distribution of characteristic(s) in the underlying population from which the data is drawn, as well as

A partitioned survival model is a type of economic model used to follow a theoretical cohort through time as they move between a set of exhaustive and mutually exclusive health

Patient access schemes (PASs) are pricing agreements proposed by pharmaceutical companies to enable patients to gain access to drugs or other treatments that may not be considered to be cost

A patient-level simulation is a type of model in which outcomes are estimated for individual patients one at a time. In this model, the determination of outcomes is usually based

Patient-reported experience measures (PREMs) are psychometrically validated tools (e.g. questionnaires) used to capture patients’ interactions with healthcare systems and the degree to which their needs are being met. PREMs are

Patient-reported outcomes (PROs) are any reports directly from patients on their health, condition, etc. that is made solely by such patients without any input, suggestions or interpretation from their doctors, family, friends or

Patient-reported outcome measures (PROMs) or instruments (more commonly used in the US) are psychometrically validated tools (e.g. questionnaires) used to collect patient-reported outcomes. In clinical trials, PROMs may be used to collect

A payer is an individual or organisation responsible for reimbursing the costs of healthcare services and products. Payers are central to healthcare systems, acting as the financial intermediary between patients

The 'perspective' is the point of view adopted in an economic evaluation when deciding which types of costs and health benefits to include. Typical perspectives are those of the patient,

The positive predictive value (PPV) is the probability that an individual who tests positive for a condition in a diagnostic or screening test actually has the condition (true positives). This

Posterior distributions (or posteriors) represent the results of a Bayesian analysis. The posteriors describe the updated probability distribution for a parameter that is calculated by combining the prior distribution with

Statistical power (1–β) relates to the ability of a study to detect an effect (or an association between two variables) when there is indeed an effect. This is the same

A pragmatic review is a literature review that adapts the conventional systematic review process to take into consideration limited time and/or resources available. This is usually achieved by applying additional limits to

Many clinical trials of new healthcare interventions, especially those required to meet the requirements of regulatory authorities, are ‘explanatory’ in nature. This means that they are executed to strict protocols,

Precision can refer to a number of different concepts. Diagnostic precision may refer to a test‘s positive predictive value or its reproducibility when repeated on the same sample (i.e. variation in results

Preference-based measures (PBM) are being increasingly used in health economic evaluations to calculate quality-adjusted life years (QALYs). Such measures usually comprise several domains (or a descriptive set) that patients can use to

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) are a set of evidence-based reporting guidelines that outline the reporting items deemed essential for maintaining a minimum level of

There are two types of prevalence in epidemiology: - Point Prevalence: The proportion of individuals in a population who have a condition at a specific point in time. - Period

In Bayesian statistics, prior distributions (or priors) represent initial beliefs abouts a parameter before new evidence or data is considered. It is a probability distribution that quantifies what is already

Probabilistic sensitivity analysis (PSA) is a technique used in economic modelling to quantify the level of confidence in the output of the analysis, in relation to uncertainty in the model

In a healthcare context, procurement is the process by which hospitals, health systems, and other organisations acquire goods, services, and works. This includes everything from buying medical supplies, pharmaceuticals, and

The Proportional Approach to Technology Appraisals (PATT) is a methodology used by NICE to tailor the evaluation process for new health technologies. This approach aims to make the appraisal process

Psychometric properties refer to the validity and reliability of patient-reported outcome measurement tools. Before being able to state that a questionnaire has excellent psychometric properties, meaning a scale is both

Publication bias describes the phenomenon where the decision to publish research findings is influenced by the nature and statistical significance of the results. Studies with statistically significant or positive outcomes

The term ‘qualitative review’ may be used either to refer to a review where the source studies reviewed report only qualitative data, or to refer to a review where the

Quality of life is a broad, multidimensional concept of an individual’s subjective evaluation of aspects of their life, including domains such as physical, social, spiritual and emotional wellbeing, as well

The quality-adjusted life year (QALY) is a summary outcome measure used to quantify the effectiveness of a particular intervention. Since the benefits of different interventions are multi-dimensional, QALYs combine the

A randomised controlled trial (RCT) is an experiment designed by investigators to study the efficacy and safety of at least two interventions in groups of randomly assigned subjects. The main

Rapid reviews (also referred to as targeted reviews) are forms of accelerated evidence synthesis in which aspects of the typical systematic review processes are streamlined or omitted. The search may

A rating scale quantifies responses to items or questions in a test, survey or questionnaire using a set of categories. These categories may take a number of formats, such as

A receiver operating characteristic (ROC) curve is a graph that shows how well a model can distinguish between two groups, such as diseased and normal. It plots the true positive

A ‘reference case’ is a formal statement of accepted methods and assumptions underpinning analyses to which health technology assessment (HTA) submissions should conform, established by some HTA bodies. The purpose

In a healthcare context, reimbursement is the payment that a healthcare provider (such as a hospital, clinic, or pharmaceutical company) receives for the medical services or products they have provided

Relative risk (RR), or risk ratio, is an estimate of the magnitude of an association between an exposure and a disease, giving the likelihood of developing the disease in the

The relative risk reduction (RRR) for an intervention, usually expressed as a percentage reduction from the risk of the comparison intervention, is commonly used as the primary result of clinical

Key psychometric requirements for patient-reported outcome measures (PROMs) include reliability, validity, and sensitivity to detect change. There are two types of reliability. The first, internal consistency, refers to how people

Reliability generalisation is a type of meta-analysis. However, rather than deriving an estimate of an overall effect size for an intervention, it provides an estimate of the internal consistency of a questionnaire,

Reporting bias is the tendency for authors to selectively use information or outcomes from investigations or trials based on certain characteristics. The dissemination of research findings may, therefore, be influenced

A synthesis of research data is the summary of the outcomes of interest for a particular research question, taken from two or more previously reported studies. Research synthesis is to

Resource use refers to the use of healthcare staff time, facilities, or consumables (especially medicines). In clinical trials and other studies, healthcare costs are frequently estimated by counting items of

Responsiveness (also known as ‘sensitivity to change’) concerns a patient-reported outcome measure's (PROM's) ability to distinguish clinically important changes because of an intervention. For a PROM to be responsive, it

Return on investment (ROI) is a performance measure used to evaluate the efficiency of a project or to compare the efficiency of a number of different projects. ROI measures the

A review of reviews is a method for synthesising evidence by compiling and summarising the findings of multiple existing systematic reviews. This approach leverages previously conducted research, making it particularly

See relative risk

Assessing the risk of bias in primary research involves evaluating of individual studies to understand their methodological limitations and potential for generating biased results. This process acknowledges that the reliability

A routine-use assessment is a type of assessment conducted by NICE for a technology or treatment that is assessed for widespread adoption and regular use within the NHS, after evidence

The integrated, rules-based MedTech pathway (RBP) is a joint initative by NHS England and NICE. The goal of the initiative is to create a unified system for evaluating, funding, and

Scientific advice is the term given to formal consultations with regulatory agencies such as the Medicines and Healthcare Products Regulatory Agency (MHRA) or health technology assessment (HTA) agencies such as

A search filter is a ready-made search strategy designed to limit search results to a set of references with specific characteristics. Filters are usually combined with a topic by using

A search strategy is a query used to retrieve information, usually from a bibliographic database. It can refer to the query used in one database or to the general approach

The sensitivity of a diagnostic (or screening) test indicates how often the test will give a positive result when the individual being tested indeed has the condition of interest. It

Sensitivity analysis is used to illustrate and assess the level of confidence that may be associated with the conclusion of an economic evaluation. It is performed by varying key assumptions

Significance level is the probability that the results observed in a study (or more extreme results) could have occurred by chance alone. It is closely associated with type 1 error

Simulated treatment comparisons (STC) are a statistical method used to compare treatments when no head-to-head trial exists. It uses individual patient data from one study to model how patients would

A single technology appraisal (STA) undertaken by UK NICE is where a (new) technology is compared with standard of care for the indication of interest. It is possible that more than

A single-arm trial is an interventional study in which all participants receive the same intervention. The defining characteristic of this type of trial is the absence of a separate control

Social cost-benefit analysis is similar to cost-benefit analysis, but it considers the monetary and non-monetary costs and benefits to society as a whole. All relevant costs and benefits are valued

Social return on investment is a performance measure similar to ‘return on investment’, but which takes a broader societal perspective to valuing costs and benefits. Social and environmental factors are considered, in

In the evaluation of diagnostic (or screening) tests, specificity refers to the proportion of the population without the condition who are correctly diagnosed as being without the condition. It is

The standard gamble (SG) method is often regarded as the most appropriate for the elicitation of utility, at least when risk is involved in decisions. This is because it follows the

Statistical significance is a measure used in hypothesis testing to determine whether the results of a study are likely to be due to chance. When a result is statistically significant,

In economic evaluation of healthcare interventions, stochastic uncertainty is one of a number of sources of uncertainty (others are parameter uncertainty, structural uncertainty and methodological uncertainty), and refers to random variation in

Structured expert elicitation (SEE) is a formal, quantitative process for gathering expert opinions on uncertain parameters, especially when empirical data is limited or unavailable. In health economics, it is used

Survival analysis is an analytical method focusing on time-to-event data. Frequently, the event is death (overall survival) but many other events can be considered in this way, such as disease

Systematic reviews adopt a rigorous scientific approach to identify and synthesise all the available evidence pertaining to a specific research question. They are carried out according to predefined protocols, which

See rapid review.

In a healthcare context, a tariff is a pre-determined price or a schedule of prices that a healthcare payer agrees to pay for a specific service or procedure. In the

Test-retest reliability is a measure of the reproducibility of the scale used within a patient-reported outcome measure (PROM); i.e. it is the ability for a PROM to provide consistent scores

The time horizon used for an economic evaluation is the duration over which health outcomes and costs are calculated. The choice of time horizon is an important decision for economic modelling and

Time trade-off (TTO) is a choice-based method of eliciting health state utility which reflects the length of remaining life expectancy that a person may be prepared to trade-off in order to

In economic evaluations, tornado diagrams are used to present the result of multiple univariate sensitivity analyses on a single graph. Each analysis is summarised using a horizontal bar which represents the variation

A true negative is a test result that correctly indicates the absence of a condition when it is, in fact, absent. For example, a diagnostic test that correctly identifies a

A true positive is a test result that correctly indicates the presence of a condition when it is, in fact, present. For example, a cancer diagnostic test that correctly identifies

Two-way sensitivity analysis is a technique used in economic evaluation to assess the robustness of the overall result (typically of a model-based analysis) when simultaneously varying the values of two

When statistically testing the results of a comparative study, two types of error can be made. A type 1 error occurs when the null hypothesis (see hypothesis testing) is rejected even

Costs used in economic evaluations are often calculated as a product of counts of items of resource use associated with a patient’s care and a standard ‘unit’ cost of each type of

Univariate/one-way sensitivity analysis allows a reviewer to assess the impact that changes in a certain input (parameter) will have on the output results of an economic evaluation (most frequently those

Uptake is the rate at which an eligible population adopts a new health technology, treatment, or intervention. It is a key concept in health economics and public health, representing the

In economic evaluation of healthcare interventions, utilities (also called health state preference values) are used to represent the strength of individuals’ preferences for different health states. When utility values are

Measures such as patient-reported outcome measures (PROMs), used within clinical trials or service evaluation, should be reliable, valid and sensitive to detect change. These are key psychometric requirements of such tools. Validity is

When used in health technology assessment, value of information (VOI) analysis is an umbrella term referring to the estimation of the value, in terms of cost and health outcomes, of

Value-based healthcare is a healthcare delivery model in which providers are paid based on patient health outcomes. Under value-based care agreements, providers are rewarded for helping patients improve their health,

Value-based pricing (also called value-optimised pricing) is a pricing strategy which sets prices primarily according to the perceived or estimated value of a product or service to customers rather than

Willingness-to-pay (WTP) is the valuation of health benefit in monetary terms, often so that this can be used in a cost-benefit analysis. The term WTP may also refer to survey techniques used