Department of Biostatistics, University of California Los Angeles (UCLA), Los Angeles, California, USA.
Stat Med. 2022 Apr 15;41(8):1498-1512. doi: 10.1002/sim.9301. Epub 2022 Jan 11.
Stepped wedge design (SWD) trials are cluster randomized trials that feature staggered, unidirectional cross-over between treatment conditions. Existing literature on power for SWDs focuses primarily on designs with two conditions, typically a control and an intervention condition. However, SWDs with more than one treatment condition are being proposed and conducted. We present a linear mixed model for SWDs with two or more interventions, including both multiarm and factorial designs. We derive standard errors of the intervention effect coefficients, and present power calculation methods. We consider both repeated cross-sectional and cohort designs. Design features, with a focus on treatment allocations, are examined to determine their impact on power.
阶梯式楔形设计 (SWD) 试验是一种群组随机试验，其特点是在治疗条件之间交错、单向交叉。关于 SWD 功效的现有文献主要集中在具有两种条件的设计上，通常是对照和干预条件。然而，正在提出和进行具有多种治疗条件的 SWD。我们为具有两种或多种干预措施的 SWD 提出了一个线性混合模型，包括多臂和析因设计。我们推导出干预效果系数的标准误差，并提出功效计算方法。我们同时考虑了重复的横截面和队列设计。我们研究了设计特点，重点是治疗分配，以确定它们对功效的影响。
