Dears at SAS,
I was trying calculate sample size for a cluster randomized control trial which has two different intervention groups and one control group (totally three groups). Is there a different assumption in sample size calculation for multiple groups other than two population proportion or mean? Is Bonferroni correction the best assumption or simply shall I use the two population and distribute it for the three groups?

I was using a formula for cluster randomized controlled trail with unequal cluster size, however, I faced difficulties in getting ICC (rho) and Coefficient of variation (CV). I didn't get a paper citing ICC and coefficient of variation and even I couldn’t get figures which enable me to calculate these constants. I was trying to calculate the average cluster size using a fixed cluster number but when I did feasibility check, the assumption was not satisfied. Do you have some advice or recommendation?

Even different people say different; the published papers even didn’t have a uniform consensus. Some paper says as I should do a simulation to have a sample size with a good power other say different. I do have three outcome variables with count and binary outcome.

Could you support me how I do simulation to determine the required sample size for a cluster randomized controlled trial which has three groups? What steps should I follow on the SAS software to calculate or simulate sample size? Which program, under the installed application there are lots of options like SAS Enterprise Guide, SAS ILM Studio, etc, should I use?
I have two types of outcomes; binary and count. The sample size I want to determine should take into consideration the following issues;

1. cluster number

2. cluster size

3. coefficient of variation

4. intracluster correlation coefficient / rho and

5. effect size

in addition to individual randomized controlled trila.

How can I determine the sample size for three groups; is the Bonferroni correction appropraite for it or is it possible two use the two population formula and then allocate for the three groups or is there any correction assumption other than this that SAS will consider?

With kind regards

Teketo Kassaw