Calculate power for the 'time x treatment' effect in two and threelevel multilevel longitudinal studies with missing data. Both the thirdlevel factor (e.g. therapists, schools, or physicians), and the secondlevel factor (e.g. subjects), can be assigned random slopes. Studies with partially nested designs, unequal cluster sizes, unequal allocation to treatment arms, and different dropout patterns per treatment are supported. For all designs power can be calculated both analytically and via simulations. The analytical calculations extends the method described in Galbraith et al. (2002) <doi:10.1016/S01972456(02)002052>, to threelevel models. Additionally, the simulation tools provides flexible ways to investigate bias, Type I errors and the consequences of model misspecification.
Package details 


Maintainer  
License  GPL (>= 3) 
Version  0.4.0.9000 
URL  https://github.com/rpsychologist/powerlmm 
Package repository  View on GitHub 
Installation 
Install the latest version of this package by entering the following in R:

Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.