Bioequivalence and Bioavailability Forum • Oops!

Oops! [Two-Stage / GS Designs]

posted by ElMaestro – Denmark, 2011-02-07 18:06 (5249 d 03:15 ago) – Posting: # 6571
Views: 26,763

Hi HS,

❝ Sure. I’m a little bit confused right now, because it seems that I misunderstood the decision procedure. Until you came up with your nice question I thought that the power calculation is done on the actual PE of stage 1 (1.08, not 0.95) and only the sample size calculation is done with 0.95 (no adaption for effect size). From the examples the former is not true – both are done with 0.95. Now I’m stuck. Potvin’s simulations were done with 0.95; is it that simple to use e.g. 0.90 instead?

I am no expert here at all.
My impression was that ordinarily a semi-blinded review of the data is done where the apparent variation is calculated and used given an assumption of the PE. I always thought about it like Heisenberg's uncertainty principle. You can't know both the PE and the CV at the interim stage.
If the PE (even though not calculated) actually deviates a lot from the assumption, then the apparent CV becomes large.

—
Pass or fail!
ElMaestro

Complete thread:

Potvin method B subtleties d_labes 2011-01-31 14:24
- Potvin method B subtleties jdetlor 2011-02-01 17:17
  - Potvin method B subtleties d_labes 2011-02-02 09:15
    - Potvin method B subtleties jdetlor 2011-02-02 16:08
      - Gould d_labes 2011-02-02 16:25
        
        Gould jdetlor 2011-02-02 17:02
- Another one ... d_labes 2011-02-07 14:32
  - Oops! Helmut 2011-02-07 15:24
    - Oops! d_labes 2011-02-07 16:29
      - Oops! Helmut 2011-02-07 16:47
        
        Oops!ElMaestro 2011-02-07 17:06
        
        Oops! Helmut 2011-02-07 17:17
        
        Oops! ElMaestro 2011-02-07 18:35
        
        Simul'ants in my pants d_labes 2011-02-08 09:07
        
        Need for speed... ElMaestro 2011-02-13 10:57
        
        Need for speed... d_labes 2011-02-15 14:06
        
        Need for speed... ElMaestro 2011-02-15 17:39
        
        Pocock alpha's d_labes 2011-02-16 09:18
        
        ElMaestro's brain ElMaestro 2011-02-16 09:32
        
        ElMaestro's brain d_labes 2011-02-16 10:05
        
        ElMaestro's brain ElMaestro 2011-02-16 12:07
        
        Numbers d_labes 2011-02-16 13:45
- Bonus counter-question ElMaestro 2011-02-07 23:44
  - Speed is the question d_labes 2011-02-08 08:36
- New paper (method D for PE 0.90) Helmut 2011-04-18 12:58
  - New paper (method D for PE 0.90) d_labes 2011-04-19 08:58
    - New paper (method D for PE 0.90) Helmut 2011-04-19 14:30
    - New paper (method D for PE 0.90) ElMaestro 2011-04-19 14:49
      - Stopping criterion # futility rule Helmut 2011-04-19 15:28