Bioequivalence and Bioavailability Forum 15:08 CET

Main page Policy/Terms of Use Abbreviations Latest Posts

 Log in |  Register |  Search

Stop estimating post hoc power! [Power / Sample Size]

posted by ElMaestro - Denmark, 2017-12-26 14:11  - Posting: # 18087
Views: 12,256

Hi kms.srinivas,


I know this post-hoc power business can be very tricky.

Try and ask yourself which question post-hoc power actually answers. Try and formulate it in a very specific sentence.

Generally, [given a statistical model] power is the chance of showing BE in a trial if your expectations about GMR, CV are correct when you use N subjects.
Choice of GMV, CV and N to plug in a power calculation is up to the user, but in the specific case of post-hoc power stats software may make such a choice for you without asking. Often it is 95% or 100% regardless of what you observed in the previous trial.

So with this in mind try and look back in your figures and tell which question the post-hoc calculation in your case gave an answer to. Feel free to paste your numbers here then I am sure someone can help working it out. You might get surprised.:-)

if (3) 4

Best regards,
ElMaestro

"(...) targeted cancer therapies will benefit fewer than 2 percent of the cancer patients they’re aimed at. That reality is often lost on consumers, who are being fed a steady diet of winning anecdotes about miracle cures." New York Times (ed.), June 9, 2018.

Complete thread:

Activity
 Mix view
Bioequivalence and Bioavailability Forum |  Admin contact
18,883 posts in 4,027 threads, 1,271 registered users;
online 33 (0 registered, 33 guests [including 29 identified bots]).

Those who make no mistakes are making the biggest mistakes of all –
they are attempting nothing new.    Anthony de Mello

The BIOEQUIVALENCE / BIOAVAILABILITY FORUM is hosted by
BEBAC Ing. Helmut Schütz
HTML5 RSS Feed