Bioequivalence and Bioavailability Forum

Dear d_labes,

thanks for your input.

❝ I'm not sure if you really need the stage x treatment interaction in stage 2 model. If you apply the same prerequisite like Potvin et.al. "... Does not require poolability criteria (or at least should know whether results from both stages are poolable before sample analysis, i.e. base poolability on study conduct such as subject demographics, temporal considerations, use of same protocol, use of same site, etc., rather than a statistical test of poolability)." then IMHO the model with treatment + stage is sufficient.

OK, my general impression is that it is desirable to factor in as much as possible in the model, so that all factors and combinations are accounted for in order to get a residual that only reflects random noise. As a side effect this reduces the residual as much as possible which is in a sponsor's interest. The latter, however, is not an argument but just a fact, I think.

At a general level I am not sure I realise when one would not specify "everything", despite the quote from Potvin's paper. Are you able to elaborate?

Many thanks,
EM.