A0433
Title: A new evaluation strategy for diagnostic tests under umbrella or tree ordering
Authors: Duc-Khanh To - Faculty of Mathematics and Computer Science, VNUHCM-US (Vietnam) [presenting]
Gianfranco Adimari - University of Padua (Italy)
Monica Chiogna - University of Bologna (Italy)
Abstract: In medical research, diagnostic tests (or biomarkers) with continuous values are widely employed to attempt to distinguish between diseased and non-diseased subjects. The diagnostic accuracy of a test can be assessed by its receiver operating characteristic (ROC) curve. For diseases with multi-classes, an important category of scenarios assumes tree or umbrella ordering, where the test measurement for one particular class is lower or higher than those for the other classes. A new ROC framework is presented for tree or umbrella ordering, together with a related evaluation strategy. Such a strategy is based on new ROC representations on the plane, denoted as LTROC and UTROC, and new summary indexes. The new tools are presented in the case of tree ordering since their specification in the case of umbrella ordering is easily tractable. The associated statistical inference is also discussed. In particular, simple estimation and interval estimation procedures are presented in a nonparametric setting. Finally, the proposed approach is illustrated with a real data example.
