Hi Everyone,
Dr. McCulloch sent the resources below for guidance power/sample size calculations when you are doing multivariate models.
Best,
Erin
The correction for adjusting for confounders is in the sample size section of my book at the end of the chapters on regression, logistic regression and survival analysis. Attached is an excerpt for the logistic regression chapter (e.g., equation (5.16) for sample size). For sample size, you do the usual calculation and then divide by (1-R^2) to inflate the answer to get the needed sample size with adjustment. So if the correlation was moderate at .5 the R^2 would be 0.25 and the inflation factor would be 1/(1-.25)=1/.75 = 1.33 or a 33% inflation.
The book is a free download as long as you are on the campus VPN:
https://link.springer.com/book/10.1007/978-1-4614-1353-0