Sequential design for paired ordinal categorical outcome

This study addresses a critical gap in the design of clinical trials that use grouped sequential designs for one-sample or paired ordinal categorical outcomes. Single-arm experiments, such as those using the modified Rankin Scale in stroke trials, underscore the necessity of our work. We present a novel method for applying the Wilcoxon signed-rank test to grouped sequences in these contexts. Our approach provides a practical and theoretical framework for assessing treatment effects, detailing variance formulas and demonstrating the asymptotic normality of the U-statistic. Through simulation studies and real data analysis, we validate the empirical Type I error rates and power. Additionally, we include a comprehensive flowchart to guide researchers in determining the required sample size to achieve specified power levels while controlling Type I error rates, thereby enhancing the design process of sequential trials.