Topic: Nonparametric Analysis of Time to Event Data Under Sequential Sampling

Date:  November 16, 2004

Speaker:  Scott S. Emerson, M.D., Ph.D.

Abstract:

In the clinical trial setting and some industrial settings, it is common to collect data under a sequential sampling plan in order to minimize study costs-scientific, economic, and ethical. Such sequential sampling causes special problems in the setting of censored survival data, because the censoring distribution is generally not constant across the various interim analyses of the data. I present approaches for investigating the effect that sequential sampling can have on a study's operating characteristics, and propose modifications to the standard survival analyses which mitigate some of the issues which arise in this setting. We have found that such modifications can have relatively minor effects on the efficiency of the analytic techniques, while allowing great improvements in the ability of the sequential sampling plan to reproduce the statistical behavior of a fixed sample test.

Biography:

Scott Emerson, M.D., Ph.D., Professor of Biostatistics at the University of Washington, is an active researcher in the design, monitoring and analysis of group sequential trials.  A major focus of his research has been in the use of estimation methods to examine the robustness of inference in the setting of poorly specified stopping rules.  He serves on a number of government and industry sponsored advisory boards related to the design and monitoring of clinical trials. Computer programs that he developed for his research into group sequential methodology now form the backbone of S+SeqTrial, an S-Plus module for group sequential trial design.

Time/Location:

Please arrive at 6:00 p.m. for dinner. Dinner will be served at 6:30 p.m. followed by the presentation at 7:15 pm at the SIAM on Lake Union. It is located at 1880 Fairview Ave. E., Seattle, WA 98020 (206-323-8101).   

Dinner:

Members $15, Students $10.

If you plan to come, please RSVP to Dan Fitzsimmons at dan.k.fitzsimmons@boeing.com or Charles Phelps at cphelps@ctiseattle.com, by Monday, November 15. Please specify if you will be having dinner with us, or will be attending only the presentation.