Dear Colleagues,
I am studying to calculate the sample size of a study. We have two treatment (A and B) and we know that in a randomized study treatment A was more effective than treatment B. In the study proposed we will offer the two treatments to the participants and they will have to choose between them. We believe that 75% will choose the treatment A. In the study the participants will be able to change the treatment once. They will be followed up for at least one-year and we are interested in looking various outcomes with one of them being adherence to treatment.
Then I would like to know if anyone could give me some ideas and references. I've never read anything on sample size in which the participant choose the treatment a may change the treatment.
Thank you in advance,
Regards,
Iuri
