Grayling, Michael J. Wason, James M. S. P. Mander, Adrian Exact group sequential designs for two-arm experiments with Poisson distributed outcome variables <p>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.</p> Adaptive design;exact;interim analysis;optimal;Skellam;two-stage 2019-07-01
    https://tandf.figshare.com/articles/journal_contribution/Exact_group_sequential_designs_for_two-arm_experiments_with_Poisson_distributed_outcome_variables/8397650
10.6084/m9.figshare.8397650.v1