English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The Youden index is a popular summary statistic for receiver operatingcharacteristic curve. It gives the optimal cutoff point of a biomarker todistinguish the diseased and healthy individuals. In this paper, we propose tomodel the distributions of a biomarker for individuals in the healthy anddiseased groups via a semiparametric density ratio model. Based on this model,we use the maximum empirical likelihood method to estimate the Youden index andthe optimal cutoff point. We further establish the asymptotic normality of theproposed estimators and construct valid confidence intervals for the Youdenindex and the corresponding optimal cutoff point. The proposed methodautomatically covers both cases when there is no lower limit of detection(LLOD) and when there is a fixed and finite LLOD for the biomarker. Extensivesimulation studies and a real data example are used to illustrate theeffectiveness of the proposed method and its advantages over the existingmethods.

Semiparametric Inference of the Youden Index and the Optimal Cutoff Point under Density Ratio Models