Accurate Unconditional P-values For A Two-arm Study With Binary Endpoints

Document Type

Article

Publication Date

1-1-2018

Publication Title

Journal of Statistical Computation and Simulation

Publisher

Taylor and Francis Ltd.

Volume

88

Issue

6

First page number:

1200

Last page number:

1210

Abstract

Unconditional exact tests are increasingly used in practice for categorical data to increase the power of a study and to make the data analysis approach being consistent with the study design. In a two-arm study with a binary endpoint, p-value based on the exact unconditional Barnard test is computed by maximizing the tail probability over a nuisance parameter with a range from 0 to 1. The traditional grid search method is able to find an approximate maximum with a partition of the parameter space, but it is not accurate and this approach becomes computationally intensive for a study beyond two groups. We propose using a polynomial method to rewrite the tail probability as a polynomial. The solutions from the derivative of the polynomial contain the solution for the global maximum of the tail probability. We use an example from a double-blind randomized Phase II cancer clinical trial to illustrate the application of the proposed polynomial method to achieve an accurate p-value. We also compare the performance of the proposed method and the traditional grid search method under various conditions. We would recommend using this new polynomial method in computing accurate exact unconditional p-values. © 2018 Informa UK Limited, trading as Taylor & Francis Group.

Keywords

Global maximum; grid search; independent proportions; polynomial; unconditional tests

Language

English

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