Exact group sequential designs for two-arm experiments with Poisson distributed outcome variables
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Peer-reviewed
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Authors
Grayling, MJ
Wason, JMS
Mander, AP
Abstract
We describe and compare two methods for the group sequential design of two-arm experiments with Poisson distributed data, which are based on a normal approximation and exact calculations respectively. A framework to determine near-optimal stopping boundaries is also presented. Using this framework, for a considered example, we demonstrate that a group sequential design could reduce the expected sample size under the null hypothesis by as much as 44% compared to a fixed sample approach. We conclude with a discussion of the advantages and disadvantages of the two presented procedures.
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Keywords
Adaptive design, Skellam, exact, interim analysis, optimal, two-stage
Journal Title
Communications in Statistics - Theory and Methods
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Journal ISSN
1532-415X
1532-415X
1532-415X
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Publisher
Taylor & Francis
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Sponsorship
MRC (unknown)
This work was supported by the Medical Research Council under Grant MC_UU_00002/3 to M.J.G. and A.P.M., and Grant MC_UU_00002/6 to J.M.S.W.