摘要:The identification of the right methodology to perform binary classification based
on an observed quantitative variable is usually a complex choice. Thus, the use of
appropriate accuracy measures is crucial. In fact, the ROC curve reveals a lot of
information about the accuracy of the applied methodology for all the possible values
of the cut-point. In particular, the integral and partial areas under the ROC curve
are widely used. The φ index, in which sensitivity equals specificity, may also be
applied. Nevertheless, the accuracy at one specific cut-point may be sufficient to
assess the accuracy in some applications. Therefore, different ways to define the
optimal cut-point may be applied, such as the maximization of the Youden index,
the maximization of the concordance probability or the minimization of the distance
to the point with absence of misclassification. To compare the adequacy of these
measures, a simulation study was performed under different scenarios. The results
highlight the advantages and disadvantages of each procedure and advise the use of
the φ index.