Bioequivalence and Bioavailability Forum

❝ My questions are: (1) is it necessary to do so? regulatory or statistical basis? and (2) if yes, what 90% CIs will you recommend (Anderson-Huack's, Westlake's, Locke' exact CI, Fixed Fieller's, Mandallaz-Mau's, etc.)? Thanks.

Hi,
In a sense, the basis is empirical. It seems to work well, that's pretty much the present reason behind it. The standard way is the classic (shortest) CI. Look it up in Chow & Liu's book (Ch. 4.2.1 in the 2000 version).
When regulators have 5 minutes to assess a BE dossier then the CI is the primary thing they look at (very often 5 minutes is a reality, for reasons that go beyond the scope of this question). The anova test for treatment effect is neglected; obviously it is not problematic per se if two formulations are different. It is only problematic if they are different in a clinically significant way, and that is what the CI empirically addresses.

So I think the answer to (1) is yes, a CI is necessary, and (2) shortest.

EM.