Bioequivalence and Bioavailability Forum

Hi Hötzi,

❝ Both are fine. Note that the FDA requires tighter batch release spec’s for NTIDs. Hence, in function sampleN.NTID() of PowerTOST the default is 0.975 – contrary to the usual 0.95.

This strays away from the usually stringent scientific principles that this forum usually promotes, doesn't it?
We plug in the GMR that we think/predict/guess is a realistic and relevant indicator of relative product performance, possibly with a buffer to factor in worst cases. Habits, experience and gut feeling.
There is no divine aspect of NTID's, as far as I know, that makes them easier to copy than non-NTID's from a strict formulation perspective so I don't know if the default is much science based.
Although I am sure 0.975 is condoned by the guy in the Armani suit. He would definitely also like it for non-NTID's.

Perhaps all this boils down to the use of anything "default" in a power calculation. It is extremely handy. And it is a bit dangerous. Perhaps the world would be a better place altogether if such functions did not assume defaults for CV and GMR and designs - this would force users to actually *** badum tssss *** think just a little bit about the values they plug in before deriving a power.

OK, rant over, I'll take my medicine now. Stage III syphilis...