Department of Psychology, Arizona State University, 950 S. McAllister Ave, Tempe, AZ, 85287, USA.
Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
Behav Res Methods. 2018 Feb;50(1):285-301. doi: 10.3758/s13428-017-0870-1.
This project examined the performance of classical and Bayesian estimators of four effect size measures for the indirect effect in a single-mediator model and a two-mediator model. Compared to the proportion and ratio mediation effect sizes, standardized mediation effect-size measures were relatively unbiased and efficient in the single-mediator model and the two-mediator model. Percentile and bias-corrected bootstrap interval estimates of ab/s , and ab(s )/s in the single-mediator model outperformed interval estimates of the proportion and ratio effect sizes in terms of power, Type I error rate, coverage, imbalance, and interval width. For the two-mediator model, standardized effect-size measures were superior to the proportion and ratio effect-size measures. Furthermore, it was found that Bayesian point and interval summaries of posterior distributions of standardized effect-size measures reduced excessive relative bias for certain parameter combinations. The standardized effect-size measures are the best effect-size measures for quantifying mediated effects.
本研究考察了在单中介模型和双中介模型中，四种间接效应效应量估计的经典和贝叶斯估计器的性能。与比例和比率中介效应大小相比，标准化中介效应大小估计在单中介模型和双中介模型中相对无偏且有效。在单中介模型中，ab/s 和 ab(s )/s 的百分位和偏差校正自举区间估计在功效、I 型错误率、覆盖率、不平衡和区间宽度方面优于比例和比率效应大小的区间估计。对于双中介模型，标准化效应量估计优于比例和比率效应量估计。此外，还发现标准化效应量估计的后验分布的贝叶斯点和区间总结减少了某些参数组合下的过度相对偏差。标准化效应量估计是量化中介效应的最佳效应量估计。
