Systematic review, meta-analysis and economic modelling of ...

DOI: 10.3310/hta17010 Health Technology Assessment 2013 Vol. 17 No. 1GlossaryTechnical terms and abbreviations are used throughout this report. The meaning is usually clear fromthe context, but a glossary is provided for the non-specialist reader. In some cases, usage differs in theliterature, but the term has a constant meaning throughout this review.Cost-effectiveness acceptability curve A way of illustrating cost-effectiveness results by plotting theprobability that the intervention is cost-effective (y-axis) against the maximum that society is willing to payfor an improvement in health (x-axis).Diagnostic cohort study Diagnostic accuracy study in which a group of individuals with a suspecteddisease undergo both the index test and the reference standard, and the results of the two testsare compared.False-negative A test result erroneously indicating that a patient with a condition does not havethat condition.False-positive A test result erroneously indicating that a patient without a condition does havethat condition.Incremental cost-effectiveness ratio The difference in costs between one intervention and analternative, divided by the difference in outcomes.Quality-adjusted life-year A measure of benefit of health care combining the impact of both expectedlength of life and quality of life.Receiver operating characteristic A receiver operating characteristic curve represents the relationshipbetween the ‘true-positive fraction’ (sensitivity) and the ‘false-positive fraction’ (1 – specificity). It displaysthe trade-offs between sensitivity and specificity as a result of varying the cut-off value for positivity in caseof a continuous test result.Reference standard Established test(s) against which the accuracy of a new test for detecting aparticular condition can be evaluated.Sensitivity (true-positive rate) The proportion of individuals with the target condition in a populationwho are correctly identified by a diagnostic test.Specificity (true-negative rate) The proportion of individuals free of the target condition in apopulation who are correctly identified by a diagnostic test.Test accuracy The proportion of test results that are correctly identified by the test.True-negative A test result correctly identifying that a patient without a condition does not not havethat condition.True-positive A test result correctly identifying that a patient with a condition has that condition.© Queen’s Printer and Controller of HMSO 2013. This work was produced by Goodacre et al. under the terms of a commissioning contract issued by the Secretary of Statefor Health. This issue may be freely reproduced for the purposes of private research and study and extracts (or indeed, the full report) may be included in professional journalsprovided that suitable acknowledgement is made and the reproduction is not associated with any form of advertising. Applications for commercial reproduction should beaddressed to: NIHR Journals Library, National Institute for Health Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton SciencePark, Southampton SO16 7NS, UK.ix