Reducing sample sizes in genome scans: Group sequential study designs with futility stops

2003 ◽  
Vol 25 (4) ◽  
pp. 339-349 ◽  
Author(s):  
Inke R. König ◽  
Helmut Schäfer ◽  
Andreas Ziegler ◽  
Hans-Helge Müller
Keyword(s):  
Sample Sizes ◽  
Group Sequential ◽  
Genome Scans ◽  
Sequential Study ◽  
Study Designs

scholarly journals Optimized Group Sequential Study Designs for Tests of Genetic Linkage and Association in Complex Diseases

2001 ◽  
Vol 69 (3) ◽  
pp. 590-600 ◽  
Author(s):  
Inke R. König ◽  
Helmut Schäfer ◽  
Hans-Helge Müller ◽  
Andreas Ziegler
Keyword(s):  
Genetic Linkage ◽  
Complex Diseases ◽  
Group Sequential ◽  
Sequential Study ◽  
Study Designs

scholarly journals Smoothing Corrections for Improving Sample Size Recalculation Rules in Adaptive Group Sequential Study Designs

2021 ◽  
Author(s):  
Carolin Herrmann ◽  
Geraldine Rauch
Keyword(s):  
Sample Size ◽  
Sample Size Calculation ◽  
Evaluation Criteria ◽  
High Variability ◽  
Conditional Power ◽  
Performance Score ◽  
Group Sequential ◽  
Conditional Performance ◽  
Sequential Study ◽  
Study Designs

Abstract Background An adequate sample size calculation is essential for designing a successful clinical trial. One way to tackle planning difficulties regarding parameter assumptions required for sample size calculation is to adapt the sample size during the ongoing trial.This can be attained by adaptive group sequential study designs. At a predefined timepoint, the interim effect is tested for significance. Based on the interim test result, the trial is either stopped or continued with the possibility of a sample size recalculation. Objectives Sample size recalculation rules have different limitations in application like a high variability of the recalculated sample size. Hence, the goal is to provide a tool to counteract this performance limitation. Methods Sample size recalculation rules can be interpreted as functions of the observed interim effect. Often, a “jump” from the first stage's sample size to the maximal sample size at a rather arbitrarily chosen interim effect size is implemented and the curve decreases monotonically afterwards. This jump is one reason for a high variability of the sample size. In this work, we investigate how the shape of the recalculation function can be improved by implementing a smoother increase of the sample size. The design options are evaluated by means of Monte Carlo simulations. Evaluation criteria are univariate performance measures such as the conditional power and sample size as well as a conditional performance score which combines these components. Results We demonstrate that smoothing corrections can reduce variability in conditional power and sample size as well as they increase the performance with respect to a recently published conditional performance score for medium and large standardized effect sizes. Conclusion Based on the simulation study, we present a tool that is easily implemented to improve sample size recalculation rules. The approach can be combined with existing sample size recalculation rules described in the literature.

On the Use of Group Sequential Study Designs for the Test of Bioequivalence for Complicated Products

2017 ◽  
Vol 106 (10) ◽  
pp. 3167-3170
Author(s):  
Rajesh Krishna ◽  
Wen-Lin Luo ◽  
Patrick J. Larson ◽  
Paul H. Fackler
Keyword(s):  
Group Sequential ◽  
Sequential Study ◽  
Study Designs
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