title: Appropriate statistical methods are required to assess diagnostic tests for replacement, add-on, and triage.
abstract: OBJECTIVE
  To explain which measures of accuracy and which statistical methods should be used in studies to assess the value of a new binary test as a replacement test, an add-on test, or a triage test.
  
  
  METHODS
  Selection and explanation of statistical methods, illustrated with examples.
  
  
  RESULTS
  Statistical methods for comparative diagnostic accuracy studies are described that take into account the purpose of the new diagnostic test. Methods are described within a framework that defines the major purpose of test comparison: assessing the value of a new test as a replacement test, an add-on test, or a triage test. Methods appropriate for both unpaired and paired study designs for binary test data are given, including regression modeling of diagnostic test accuracy. Implications for efficient study designs are also discussed.
  
  
  CONCLUSIONS
  Appropriate selection of existing statistical methods is necessary to address research questions about the comparative accuracy of new tests.
authors.affiliation: Screening and Test Evaluation Program, Sydney School of Public Health, University of Sydney, Sydney, New South Wales, Australia. ahayen@health.usyd.edu.au
authors.forename: Andrew
authors.initials: A
authors.lastname: Hayen
authors.forename: Petra
authors.initials: P
authors.lastname: Macaskill
authors.forename: Les
authors.initials: L
authors.lastname: Irwig
authors.forename: Patrick
authors.initials: P
authors.lastname: Bossuyt
mesh_terms: D000328:Adult; D056808:Biostatistics; D003955:Diagnostic Tests, Routine / Q000592:standards* / Q000706:statistics & numerical data; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D016013:Likelihood Functions; D008327:Mammography / Q000592:standards*; D008875:Middle Aged; D012680:Sensitivity and Specificity; D014218:Triage / Q000592:standards*