Department of Epidemiology and Biostatistics, Indiana University School of Public Health-Bloomington, Bloomington, IN, United States of America.
Department of Applied Health Science, Indiana University School of Public Health-Bloomington, Bloomington, IN, United States of America.
PLoS One. 2022 Oct 27;17(10):e0275242. doi: 10.1371/journal.pone.0275242. eCollection 2022.
In a published randomized controlled trial, household units were randomized to a nutrient bar supplementation group or a control condition, but the non-independence of observations within the same household (i.e., the clustering effect) was not accounted for in the statistical analyses. Therefore, we reanalyzed the data appropriately by adjusting degrees of freedom using the between-within method, and accounting for household units using linear mixed effect models with random intercepts for family units and subjects nested within family units for each reported outcome. Results from this reanalysis showed that ignoring the clustering and nesting effects in the original analyses had resulted in anticonservative (i.e., too small) time x group interaction p-values. Still, majority of the conclusions remained unchanged.
在一项已发表的随机对照试验中，家庭单位被随机分配到营养棒补充组或对照组，但在统计分析中没有考虑到同一家庭内观察结果的非独立性（即聚类效应）。因此，我们通过使用基于组内-组间的方法适当调整自由度，并使用线性混合效应模型，为每个报告的结果考虑家庭单位，随机截距为家庭单位，个体嵌套在家庭单位内，对数据进行了重新分析。重新分析的结果表明，在原始分析中忽略聚类和嵌套效应会导致时间 x 组交互 p 值保守（即太小）。尽管如此，大多数结论仍然保持不变。
