Dear all,
I have a question regarding the calculation of sample size for TTO
measurement.
We are conducting a randomized clinical trial to assess the impact of a
dermatological treatment. We have a control and an intervention group and
assess outcomes at two occassions (at the beginning of the study and 12
weeks later).
We recruited a sample of 300 patients in each group. We want to conduct
TTO measurement for subsamples. Clearly, the number of 600 patients is too
large (and too expensive for TTO interviews). Has anyone suggestions,
experiences or helpful literature on the sample sizes needed for TTO
assessment? We want to compare mean utilities between the groups before
and after treatment.
Thank you very much in advance for your help!
Best regards
Raoul
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