How to simulate a custom power analysis of an lm model (using R)

Question

Following to the recent questions we had here.

I was hopping to know if anyone had come across or can share R code for performing a custom power analysis based on simulation for a linear model?

Later I would obviously like to extend it to more complex models, but lm seems to right place to start. Thanks.

Answer 1

I'm not sure you need simulation for a simple regression model. For example, see the paper Portable Power. For more complex models, specifically mixed effects, the pamm package in R performs power analyses through simulations. Also see Todd Jobe's post which has R code for simulation.

Answer 2

Here are a few sources of simulation code in R. I'm not sure if any specifically address linear models, but perhaps they provide enough of an example to get the gist:

• Benjamin Bolker has written a great book Ecological Data and Models with R. An early draft of the whole book along with Sweave code is available online. Chapter 5 addresses power analysis and simulation.

There's another couple of examples of simulation at the following sites:

• http://www.personality-project.org/R/r.datageneration.html
• http://psy-ed.wikidot.com/simulation