JSM 2015 Preliminary Program

Online Program Home
My Program

Abstract Details

Activity Number: 353
Type: Contributed
Date/Time: Tuesday, August 11, 2015 : 10:30 AM to 12:20 PM
Sponsor: Biopharmaceutical Section
Abstract #317653
Title: Unconditional Exact Tests for Binomial Proportions in the Group Sequential Setting
Author(s): Navneet Hakhu* and Scott Emerson
Companies: Axio Research and University of Washington
Keywords: unconditional exact test ; binomial proportions ; group sequential ; randomized clinical trials
Abstract:

Exact inference for independent binomial outcomes in small samples is complicated by the presence of a mean-variance relationship that depends on nuisance parameters, discreteness of the outcome space, and departures from normality. To address the various issues, Barnard introduced the concept of unconditional exact tests that use exact distributions of a test statistic evaluated over all possible values of the nuisance parameter. It has been found that unconditional exact tests are preferred to conditional exact tests in fixed sample settings. In this presentation we examine the behavior of unconditional exact tests using Wald, score, likelihood ratio, and Fisher's exact test statistics in the group sequential setting. We suggest three methods of using critical values derived from adjusted fixed sample tests in order to minimize the conservativeness of the actual type 1 error at: the final analysis only; each analysis after 50% accrual of the maximal sample size; and every analysis. Owing to its tendency to behave well across a wide variety of settings, we recommend implementation of the unconditional exact test using the adjusted Fisher's exact test statistic at every analysis.


Authors who are presenting talks have a * after their name.

Back to the full JSM 2015 program





For program information, contact the JSM Registration Department or phone (888) 231-3473.

For Professional Development information, contact the Education Department.

The views expressed here are those of the individual authors and not necessarily those of the JSM sponsors, their officers, or their staff.

2015 JSM Online Program Home