Bioequivalence and Bioavailability Forum

Hi all,

❝ Phantastic № 2! Of course post hoc power is irrelevant in BE, but obviously these guys (of the agency or – even worse – the BSWP) did|do not comprehend the intermediate [sic] power estimation is part of the framework of Potvin et al. & Montague et al.

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❝ ❝ I don't know how many ways we can interpret this phrase.

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❝ Stupidity? Especially “The decision can not depend on the results of the power.” WTF does the apodictic “can not” mean? OK, the framework showed that α is maintained. Of course this does not imply that skipping this step will not work at well. We just don’t have any evidence (i.e., a published reference). I don’t have the means to set up simulations but would be a rather interesting task. ElMaestro?

Yes, I can certainly set up some new simulations if necessary although this will be a spare time project and may take a lot of time. The author of the crackpot paper used at least what corresponds to two full months work time just to do the necessary programming, so I've heard.

One thing I learned from the 2010 revision (subjects as fixed even in replicate designs) is that regulators are not likely to admit when they have issued wobbly statements (I could use the term 'made mistakes' but have deliberately chosen not to). This is possibly just the human nature?!? Therefore, I am inclined to think that we need to think of a way to create a win-win situation so that whatever is the result of future simulations is something that allows regulators to lean back in the armchair with a cognac and think "Yeah, we were right. Again."
Probably they just mean that classically, power is not associated with regulatory risk (patient's risk) and therefore it isn't what their concern is. But for 2-stage designs, one may argue exceptions to this true general rule exist.
I am bewildered though, I am not sure what to simulate. If you guys can propose an Al Gore Rhythm (please make a graphic) then this would be a good starting point. Is it possible to write one which does not involve intermediary power steps? I mean, at the end we do need to think about how many subjects to include at stage 2 and that means power doesn't it (and don't we)? Lemme hear some more thoughts, please; I find it very interesting and this discussion very inspiring.