ROC Curves in Non‐Parametric Location‐Scale Regression Models

Abstract. The receiver operating characteristic (ROC) curve is a tool of extensive use to analyse the discrimination capability of a diagnostic variable in medical studies. In certain situations, the presence of a covariate related to the diagnostic variable can increase the discriminating power of the ROC curve. In this article, we model the effect of the covariate over the diagnostic variable by means of non‐parametric location‐scale regression models. We propose a new non‐parametric estimator of the conditional ROC curve and study its asymptotic properties. We also present some simulations and an illustration to a data set concerning diagnosis of diabetes.     

An Age-Structured Model for Childhood Obesity

An age-structured model for childhood obesity at population level is fitted to empirical data in order to predict the proportion of overweighted and obese children in the 6–8 and 9–12 year old classes in the region of Valencia, Spain.     

Testing Constancy for Isotonic Regressions

Abstract.  In this paper, we propose a bootstrap method for testing the constancy of an isotonic regression. The technique we develop is completely non-parametric and enlarges the appli-cability of the classical chi-bar-squared tests, which require normality assumptions. We prove that our procedure is asymptotically correct and consistent. Moreover, by means of simulations we show that it behaves suitably in practice, and similarly to the chi-bar-squared tests under normality. Finally, we illustrate the method with the study of a real case that is well known in the related literature.