Cumulative Meta-Analysis
Cumulative meta-analysis is a meta-analysis repeated as each new study is added, usually by date, showing how the pooled effect and its uncertainty evolve.
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.
Concepts, entries and ontology terms
A concept page is a published entry on the wiki. Some concepts also have a full encyclopaedia article. The Health Economics Ontology (HEO) holds every concept, including dictionary terms without an article, so it is larger than the list of published pages. The knowledge graph shows how concepts relate to each other.
Data Extraction
Data extraction is the recording of study details and results on a structured form for use in a systematic review, meta-analysis or economic model.
Data Mining
Data mining is the computational search of large health datasets, such as claims or patient records, for patterns that were not specified in advance.
Data Pooling
Data pooling is the statistical combining of results from several studies into one summary estimate, usually weighting each study by its precision.
Data Quality
Data quality is the fitness of data for a specific use in health research or HTA, judged by completeness, accuracy, consistency, timeliness and relevance.
Data Safety Monitoring Board
Data Safety Monitoring Board (DSMB) is an independent committee that reviews unblinded interim trial data and advises whether to continue, change or stop.
Decision Curve Analysis
Decision curve analysis (DCA) plots the net benefit of a prediction model or test across risk thresholds against treating all or no patients.
Degrees of Freedom
Degrees of freedom (df) count values left free to vary after estimation and set the t, chi-squared or F curve for tests in trials and meta-analyses.
Delta Method
The delta method approximates the variance of a function of estimated parameters, such as an ICER or mean survival, using a first-order Taylor expansion.
Descriptive Epidemiology
Descriptive epidemiology describes how disease is distributed by person, place and time, supplying the counts, rates and trends used in health economics.
Descriptive Statistics
Descriptive statistics summarise the centre, spread and shape of data, such as skewed patient costs, whose arithmetic mean sets the total budget.
Design Effect
The design effect (DEFF) is the ratio of an estimate's variance under a clustered or complex sample to that under a simple random sample of equal size.
Detection Bias
Detection bias is systematic error from unequal finding, measuring or judging of outcomes between study groups, often because assessors know allocation.
Diagnostic Accuracy
Diagnostic accuracy is how well a test agrees with a reference standard in detecting a target condition, usually reported as sensitivity and specificity.
Diagnostic Model
A diagnostic model is a multivariable prediction model estimating the probability a condition is present now, to guide testing, referral and treatment.
Difference-in-Differences
Difference-in-differences (DiD) estimates a policy's causal effect by comparing outcome changes over time in an exposed group and a comparison group.
Discrete Data
Discrete data are values that can only be counted in whole steps, such as the number of hospital admissions, GP visits or exacerbations per patient.
Discriminant Validity
Discriminant validity is evidence that a health measure correlates less with measures of other constructs than with its own, as predicted in advance.
Disease-Free Survival
Disease-free survival (DFS) is the time from randomisation until cancer recurrence or death from any cause, an endpoint of adjuvant trials and models.
DLQI
DLQI is a ten-question skin-specific quality of life questionnaire scored 0 to 30, used in dermatology trials and NICE appraisals to define response.