Full ACK [Power / Sample Size]

posted by d_labes  – Berlin, Germany, 2017-12-28 17:41  – Posting: # 18116
Views: 22,112

Dear David,

» In this case, given your simulations above and the expected probability of approximately 12% of the studies having power greater then 95% having in consideration the initial assumptions, post hoc power means nothing.

Full ACK.
But not only in this case, also in other cases. The concept of post-hoc power is flawed by its own.

» But if you had 100 studies instead and 90% of the had >95% power although the sample size was calculated assuming expected power of 80%, some questions and conclusions might be drawn from those results, don't you think? From my understanding of the initial question, this was the case found. So I think that they should start by reviewing how they define their assumptions for the sample size, namely why they assume GMR=1.10 instead of the "normal" 0.95/1.05.

Again: Full ACK.

Regards,

Detlew

Complete thread:

Activity
 Mix view
Bioequivalence and Bioavailability Forum |  Admin contact
19,873 posts in 4,214 threads, 1,366 registered users;
online 11 (1 registered, 10 guests [including 7 identified bots]).
Forum time (Europe/Vienna): 13:40 CEST

Statistics. A sort of elementary form of mathematics which consists of
adding things together and occasionally squaring them.    Stephen Senn

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