Bioequivalence and Bioavailability Forum • two-stage design power 90% in sample size adaption

two-stage design power 90% in sample size adaption [Two-Stage / GS Designs]

posted by Yvonne – 2012-08-02 14:06 (5078 d 00:12 ago) – Posting: # 9024
Views: 17,813

Hi

Thank you for your answer

❝ They are right. The alpha may go a little up.

❝ Example: T/R=0.9 at CV=0.3 and N1=24 (method B). Alpha is around 0.0529 (Montague's paper) with target power 0.8 but with target power 0.9 alpha increases to 0.0543 (1 million sims).

So as what I understand, you need to calculate your sample size in the second stage with an alpha < 0.0294 to control alpha inflation. But how far should we decrease (most likely dependent on the CV in the first stage) and is it accepted to decrease alpha in stage 2 (and thus deviate from potvin method C)?

Regards,

Yvonne

Complete thread:

two-stage design power 90% second stage Yvonne 2012-08-02 09:50 [Two-Stage / GS Designs]
- two-stage design power 90% second stage ElMaestro 2012-08-02 10:17
  - two-stage design power 90% second stage Yvonne 2012-08-02 11:47
    - two-stage design power 90% second stage ElMaestro 2012-08-02 11:54
- two-stage design power 90% in sample size adaption d_labes 2012-08-02 10:33
  - two-stage design power 90% in sample size adaption ElMaestro 2012-08-02 11:29
    - two-stage design power 90% in sample size adaptionYvonne 2012-08-02 12:06
      - two-stage design power 90% in sample size adaption ElMaestro 2012-08-02 16:59
- Are simulations sufficient? …lenghty post! Helmut 2012-08-02 17:39
  - adjusted alpha = 0.045 d_labes 2012-08-03 11:33
    - adjusted alpha = 0.038 Helmut 2012-08-03 14:26
      - adjusted alpha by sims? d_labes 2012-08-03 15:48
        
        Yeah but, no but, yeah but, no but… Helmut 2012-08-03 16:39
        
        Yeah but, no but ... d_labes 2012-08-07 14:42
        
        Yeah but, no but ... Helmut 2012-08-07 15:14