Hi everybody, I am writing because I need some advise on how to conduct an a priori power analysis to determine the sample size for a model that has several mediators.

I will be conducting an experiment with three different experimental conditions, and I want to address both their direct effect on three different dependent variables (a continuous one and two dichotomous), and also their indirect effects via five simultaneous mediators.

Unfortunately I have not yet found a way for doing so. The only tool I found (the one developed by Schoemann, Boulton, & Short, 2017), based on Monte Carlo simulations, only allows to estimate sample sizes for models with up to two mediators.

I would really appreciate if somebody can help me with this. Thanks in advance!!!