Power Calculation using Stata


New Member

I am involved in a clinical study where I need to ascertain that the study has adequate power. The study aims at understanding the effect of a program on patients. We are required to have a control and a treatment sample. I believe I can recruit about 22 individuals for the study in each group. We think a repeated measures approach (observation at time =0, time =3months, time =6 months) would be best. Could you please help me understand how I can do a power calculation using STATA for such a project? I have heard about "sampsi" but am not sure if that would help. Please advise.


What outcome will you be measuring? Is it continuous, categorical..? What statistical tests are you planning? Do you have any pilot data to assist your calculations?

sampsi can do a fair bit, but it seems to me to be a little limited for repeated measures.