title: An additive selection of markers to improve diagnostic accuracy based on a discriminatory measure.
abstract: OBJECTIVE
  The estimation of the area under the receiver operating characteristic (ROC) curve (AUC) often relies on the assumption that the truly positive population tends to have higher marker results than the truly negative population. The authors propose a discriminatory measure to relax such an assumption and apply the measure to identify the appropriate set of markers for combination.
  
  
  METHODS
  The proposed measure is based on the maximum of the AUC and 1-AUC. The existing methods are applied to estimate the measure. The subset of markers is selected using a combination method that maximizes a function of the proposed discriminatory score with the number of markers as a penalty in the function.
  
  
  RESULTS
  The properties of the estimators for the proposed measure were studied through large-scale simulation studies. The application was illustrated through a real example to identify the set of markers to combine.
  
  
  CONCLUSIONS
  Simulation results showed excellent small-sample performance of the estimators for the proposed measure. The application in the example yielded a reasonable subset of markers for combination.
authors.affiliation: Department of Statistics, George Mason University, Fairfax, VA, USA.
authors.forename: Liansheng Larry
authors.initials: LL
authors.lastname: Tang
authors.forename: Le
authors.initials: L
authors.lastname: Kang
authors.forename: Chunling
authors.initials: C
authors.lastname: Liu
authors.forename: Enrique F
authors.initials: EF
authors.lastname: Schisterman
authors.forename: Aiyi
authors.initials: A
authors.lastname: Liu
mesh_terms: D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood; D002648:Child; D002659:Child Development Disorders, Pervasive / Q000097:blood*; D002675:Child, Preschool; D003198:Computer Simulation; D016002:Discriminant Analysis; D006801:Humans; D012372:ROC Curve; D015203:Reproducibility of Results
chemical_list: D015415:Biomarkers