Bioequivalence and Bioavailability Forum

Hello Helmut,

thank you for a well-explained answer with specific examples.

❝ In a 2×2×2 crossover with subject(s) missing one period you get (apart from a slight difference in the n^th figure, which is not relevant) the same result for a mixed effects model with all subject(s) and a fixed effects model excluding the subject(s) with missings.

Doesnt a model with subject as a fixed effect automatically exlude subjects with missing periods (in 2x2x2 design) from the analysis? Or am I wrong?
If I am not wrong and if I understand correctly, based on your examples with incomplete data (periods missing), the difference between subject as a fixed effect and subject as a mixed effect is more than a slight difference (instead the difference is observed in the 1st decimal place)?

❝ However, I would still use a mixed effects model for the FDA and Health Canada and a fixed effects model for all other agencies. We don’t want to confuse assessors who are used to what they required for ages.

I agree

❝ There are differences for incomplete data (period missing) – not only for the CI but also the PE. However, in such a case the subject should be excluded according to M13A and its Q&A anyway.

Yes I was most interested in these incomplete data. So basically if you have incomplete data set (just periods missing) you should exclude the subject from the analysis and then the result (PI and 90%CI) would be almost the same (regardless of subject as a fixed or mixed effect)? Furthermore, this result would again be almost the same as if we wouldnt exclude the subject from the analysis and just used subject as a fixed effect?