Cost-effectiveness analysis is a widely used educational evaluation tool. The randomized controlled trials that aim to evaluate the cost-effectiveness of the treatment are commonly referred to as randomized cost-effectiveness trials (RCETs). This study provides methods of power analysis for two-level multisite RCETs. Power computations take account of sample sizes, the effect size, covariates effects, nesting effects for both cost and effectiveness measures, the ratio of the total variance of the cost measure to the total variance of effectiveness measure, and correlations between cost and effectiveness measures at each level. Illustrative examples that show how power is influenced by the sample sizes, nesting effects, covariate effects, and correlations between cost and effectiveness measures are presented. We also demonstrate how the calculations can be applied in the design phase of two-level multisite RCETs using the software PowerUp!-CEA (Version 1.0).

中文翻译：

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两级多站点随机成本效益试验的功效分析

成本效益分析是一种广泛使用的教育评估工具。旨在评估治疗成本效益的随机对照试验通常称为随机成本效益试验（RCET）。本研究提供了两级多站点RCET的功率分析方法。功效计算考虑以下因素：样本量，效应量，协变量效应，成本和有效性度量的嵌套效应，成本度量的总方差与有效性度量的总方差之比，以及成本和有效性度量之间的相关性每个级别。提供了说明性示例，这些示例说明了样本量，嵌套效应，协变量效应以及成本与有效性度量之间的相关性如何影响功效。