Date: 2016-10-28

Time: 15:30-16:30

Location: BURN 1205

Abstract:

Two-phase studies are frequently used when observations on certain variables are expensive or difficult to obtain. One such situation is when a cohort exists for which certain variables have been measured (phase 1 data); then, a sub-sample of individuals is selected, and additional data are collected on them (phase 2). Efficiency for tests and estimators can be increased by basing the selection of phase 2 individuals on data collected at phase 1. For example, in large cohorts, expensive genomic measurements are often collected at phase 2, with oversampling of persons with “extreme” phenotypic responses. A second example is case-cohort or nested case-control studies involving times to rare events, where phase 2 oversamples persons who have experienced the event by a certain time. In this talk I will describe two-phase studies on failure times, present efficient methods for testing covariate effects. Some extensions to more complex outcomes and areas needing further development will be discussed.

Speaker

Jerry Lawless is a Distinguished Professor Emeritus in the Department of Statistics and Actuarial Science at the University of Waterloo. He has been a consultant to industry and government, is a past editor of Technometrics and a past president of the Statistical Society of Canada. He is a Fellow of the American Statistical Association (1983) and of the Institute of Mathematical Statistics (1990), and a recipient of the Gold Medal of the Statistical Society of Canada (1999). He was elected a Fellow of the Royal Society of Canada in 2000.