title: A receiver operating characteristic partial area index for highly sensitive diagnostic tests.
abstract: OBJECTIVE
  Area under a receiver operating characteristic (ROC) curve (Az) is widely used as an index of diagnostic performance. However, Az is not a meaningful summary of clinical diagnostic performance when high sensitivity must be maintained clinically. The authors developed a new ROC partial area index, which measures clinical diagnostic performance more meaningfully in such situations, to summarize an ROC curve in only a high-sensitivity region.
  
  
  METHODS
  The mathematical formation of the partial area index was derived from the conventional binormal model. Statistical tests of apparent differences in this index were formulated analogous to that of Az. One common statistical test involving the partial area index was validated by computer simulations under realistic conditions.
  
  
  RESULTS
  An example in mammography illustrates a situation in which the partial area index is more meaningful than Az in measuring clinical diagnostic performance.
  
  
  CONCLUSIONS
  The partial area index can be used as a more meaningful alternative to the conventional Az index for highly sensitive diagnostic tests.
authors.affiliation: Department of Radiology, Kurt Rossmann Laboratories for Radiologic Image Research, University of Chicago, IL 60637, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Jiang
authors.forename: C E
authors.initials: CE
authors.lastname: Metz
authors.forename: R M
authors.initials: RM
authors.lastname: Nishikawa
mesh_terms: D012372:ROC Curve; D011871:Radiology; D012680:Sensitivity and Specificity