Simulations mandatory [Two-Stage / GS Designs]

posted by Helmut Homepage – Vienna, Austria, 2024-01-09 10:31 (161 d 05:16 ago) – Posting: # 23824
Views: 4,372

Hi Achievwin,

❝ Thank you for your nice reply.

Welcome.

Just to be clear: Some authors (right now I’m reviewing a manuscript submitted to Stat Med…) believe (‼) that Pocock’s \(\small{\color{Blue}{\alpha_\text{adj}=0.0294}}\) (94.12% CI) is ‘uni­versally’ valid – even for reference-scaling of HVDs. This is a gross misunderstanding and not even wrong. It was derived for superiority testing in a GSD (fixed sample size N) with one interim at – exactly – N/2 and known variances. The fact that it controlled the Type I Error in Pot­vin’s Method B (TSD in a 2×2×2 design) was a mere lucky punch.
In my example I needed \(\small{\color{Red}{\alpha_\text{adj}=0.0274}}\) (94.52% CI) to control the Type I Error.

Dif-tor heh smusma 🖖🏼 Довге життя Україна! [image]
Helmut Schütz
[image]

The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes

Complete thread:

UA Flag
Activity
 Admin contact
23,057 posts in 4,840 threads, 1,641 registered users;
73 visitors (0 registered, 73 guests [including 6 identified bots]).
Forum time: 16:48 CEST (Europe/Vienna)

You should treat as many patients as possible with the new drugs
while they still have the power to heal.    Armand Trousseau

The Bioequivalence and Bioavailability Forum is hosted by
BEBAC Ing. Helmut Schütz
HTML5