Bioequivalence and Bioavailability Forum • Yeah but, no but ...

Yeah but, no but ... [Two-Stage / GS Designs]

posted by Helmut – Vienna, Austria, 2012-08-07 17:14 (4702 d 06:23 ago) – Posting: # 9047
Views: 14,743

Dear Detlew!

❝ ❝ […] If one follows Method B, IMHO a posteriori simulations are not necessary if the study was planned with a n₁ corresponding to max. α_emp.. That would mean that we are already on ‘top of the ridge’.

❝

❝ Beeing on the ‘top of the ridge’ would mean IMHO that we are practically working with alpha_1,2 = 0.0294.

Exactly. That’s what I mean by “if the study was planned with a n₁ corresponding to max. α_emp.” above.

❝ Another rather clear message of this nice picture: Don't use n1 as low as 12 ('internal pilot' in the usual understanding of many sponsors) if the anticipated CV is >25%.

Yep. I was always preaching (though in the context of ‘classical’ pilot studies) against too small sample sizes if the anticipated CV is large.

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Complete thread:

two-stage design power 90% second stage Yvonne 2012-08-02 09:50
- 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 adaption Yvonne 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