At any point on a receiver operating characteristic (ROC) curve in combination with two distributions of genuine scores and impostor scores, there are three related variables: the true accept rate (TAR) of the genuine scores, the false accept rate (FAR) of the impostor scores, and the threshold. Any one of these three variables determines the other two variables. The measures and accuracies of ...

• This article reviews current state of the art of ROC surface analysis and illustrates its use through an application on a pancreatic cancer diagnostic marker. Receiver Operating Characteristic (ROC) surfaces have been studied in the literature essentially only during the last decade and are considered as a natural generalization of ROC curves in three-class diagnostic problems. This article p...

The paper presents a new method of sample size determination (SSD) based on performance evaluation of systems under study. The method builds upon previous work on Bayesian approach to nonparametric receiver operating characteristics (ROC) analysis with estimation of probability density functions and confidence intervals for parameters of ROC curve. Technical details of the method together with ...

Aim—frailty is an emerging concept in primary care, which potentially can provide healthcare commissioners with a clinical focus for targeting resources at an ageing population. However, primary care practitioners need valid instruments that are easy to use. With that purpose in mind, we created a Frailty Instrument (FIt) for primary care based on the Survey of Health, Ageing and Retirement in ...

• The accuracy of a binary diagnostic test can easily be assessed by comparing the sensitivity and specificity with the status of respondents. When the result of a diagnostic test is continuous, the assessment of accuracy depends on a specified threshold. The receiver operating characteristic (ROC) curve, which includes all possible combinations of sensitivity and specificity, provides an appro...

Regression models are introduced into the receiver operating characteristic (ROC) analysis to accommodate effects of covariates, such as genes. If many covariates are available, the variable selection issue arises. The traditional induced methodology separately models outcomes of diseased and nondiseased groups; thus, separate application of variable selections to two models will bring barriers...

In the field of diagnostic test studies, the accuracy of a diagnostic test is essential in evaluating the performance of the test. The receiver operating characteristic (ROC ) curve and the area under the curve (AUC ) are widely used in such evaluation procedures. Meanwhile, the Youden index is also introduced into practice to measure the accuracy of the diagnostic test from another aspect. The...

Objectives: The aim of this retrospective study was to clarify whether plasma markers that are routinely used in the workup of patients suspected for acute appendicitis (AA) can stratify for imaging in both adults and children. Methods: A total of 1388 patients suspected of AA between January 2008 and till 2012 were included. CRP and WBC concentrations were retrospectively abstracted from the e...

One of the main drawbacks of using endometrial cytology in cows is the time required for sample collection and interpretation. It is recommended to count a large number of polymorphonuclear neutrophils (PMN) and to calculate their overall percentage. However, since counting a large number of cells is a laborious method, it would be preferable to simplify the analysis by counting the number of P...