title: Accuracy and cut-off point selection in three-class classification problems using a generalization of the Youden index.
abstract: We study properties of the index J(3), defined as the accuracy, or the maximum correct classification, for a given three-class classification problem. Specifically, using J(3) one can assess the discrimination between the three distributions and obtain an optimal pair of cut-off points c(1)<c(2) in the sense that the sum of the correct classification proportions will be maximized. It also serves as the generalization of the Youden index in three-class problems. Parametric and non-parametric approaches for estimation and testing are considered and methods are applied to data from an MRS study on human immunodeficiency virus (HIV) patients.
authors.affiliation: Laboratory of Biometry, University of Thessaly, Fytokou Str, N. Ionia, 384 46 Magnesia, Greece. cnakas@gmail.com
authors.forename: Christos T
authors.initials: CT
authors.lastname: Nakas
authors.forename: Todd A
authors.initials: TA
authors.lastname: Alonzo
authors.forename: Constantin T
authors.initials: CT
authors.lastname: Yiannoutsos
mesh_terms: D015526:AIDS Dementia Complex / Q000175:diagnosis; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000032:analysis; D015982:Bias; D015415:Biomarkers / Q000032:analysis*; D056808:Biostatistics / Q000379:methods*; D002965:Classification / Q000379:methods*; D003198:Computer Simulation; D003401:Creatine / Q000032:analysis; D003627:Data Interpretation, Statistical; D003955:Diagnostic Tests, Routine / Q000706:statistics & numerical data*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D015233:Models, Statistical; D012372:ROC Curve; D018709:Statistics, Nonparametric
chemical_list: D015415:Biomarkers; D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine
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