The series hosts a seminar every other week on current research topics. The seminar often features an invited guest speaker and occasionally local faculty members, students or others affiliated with the department. The usual time of the seminar is 3:30-4:30 pm on Fridays. Professors Tatiyana V Apanasovich (email@example.com), Qing Pan (firstname.lastname@example.org) and Emre Barut (email@example.com ) are the Seminar Series Coordinators.
Date: Friday, April 29th, 3:30-4:30pm
Location: Duques Hall, Room 359
Title: Flexible Regression Models for ROC and Risk Analysis, With or Without a Gold Standard
Speaker: Wesley O. Johnson, Dept. of Statistics, UC Irvine
Abstract: A novel semiparametric regression model is developed for evaluating the covariate-specific accuracy of a continuous medical test or biomarker. Ideally, studies use a separate, flawless gold-standard procedure to determine the true disease status of sampled individuals. But it is increasingly common that disease status is unknown because a gold-standard procedure does not exist or is too costly or invasive for widespread use. To compensate for missing data on disease status, covariate information is used to help discriminate between diseased and healthy units. We thus model the probability of disease as a function of "disease covariates." In addition, we model test/biomarker outcome data to depend on "test covariates." We also model the distributions of test outcomes using flexible semiparametric classes. The modeling framework can be used to obtain inferences about (i) covariate-specific test accuracy and (ii) the probability of disease based on subject-specific disease and test covariate information. The model is illustrated using data on the age-adjusted ability of soluble epidermal growth factor receptor to serve as a biomarker of lung cancer in menh.