https://communities.sas.com/t5/Statistical-Procedures/Sampling-design/m-p/760345#M37046 Dear Reeza,<BR />thanks a lot.<BR />Regards,<BR /><BR />Iuri Mon, 09 Aug 2021 12:22:44 GMT iuri_leite 2021-08-09T12:22:44Z https://communities.sas.com/t5/Statistical-Procedures/Sampling-design/m-p/759994#M37023 <P>Dear Colleagues,</P><P>&nbsp;</P><P>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.</P><P>&nbsp;</P><P>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.</P><P>&nbsp;</P><P>Thank you in advance,</P><P>Regards,</P><P>Iuri</P><P>&nbsp;</P> Fri, 06 Aug 2021 15:40:39 GMT https://communities.sas.com/t5/Statistical-Procedures/Sampling-design/m-p/759994#M37023 iuri_leite 2021-08-06T15:40:39Z https://communities.sas.com/t5/Statistical-Procedures/Sampling-design/m-p/760004#M37025 That's a unique enough design I don't think there's going to be anything out there - simulation time. Fri, 06 Aug 2021 16:07:37 GMT https://communities.sas.com/t5/Statistical-Procedures/Sampling-design/m-p/760004#M37025 Reeza 2021-08-06T16:07:37Z https://communities.sas.com/t5/Statistical-Procedures/Sampling-design/m-p/760345#M37046 Dear Reeza,<BR />thanks a lot.<BR />Regards,<BR /><BR />Iuri Mon, 09 Aug 2021 12:22:44 GMT https://communities.sas.com/t5/Statistical-Procedures/Sampling-design/m-p/760345#M37046 iuri_leite 2021-08-09T12:22:44Z