Bioequivalence and Bioavailability Forum • Williams design 3-way

Williams design 3-way [Design Issues]

posted by Helmut – Vienna, Austria, 2021-06-09 17:48 (47 d 07:34 ago) – Posting: # 22399
Views: 995

Hi Brus,

» I have a question on this topic that you mentioned a long time ago: […]

Please read the entire thread. What I posted in 2007 is obsolete. See also this article.

» According to what you said, 6 sequences had to be done with a 3-way study to get balanced sequences on the two 2x2 tablets. But, with following approach, balanced sequences would also be achieved:
»
» ABC
» BAC
» CAB
» CBA

That’s not balanced for carryover. However, since we cannot correct for unequal carryover anyway (see there), we have to avoid it by design, i.e., sufficiently long washouts between treatment periods.

» It's possible? What problems would it have?

What is your idea behind such a design? Actually a simple Latin Square (ABC|BCA|CAB) would do as well. If you want to make European assessors happy, opt for the 6-sequence Williams’ design.

Most important: Evaluate the study by the ‘Two at a Time’ approach.

» It is not williams square design, right?

Correct.

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Helmut Schütz

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Complete thread:

Three-way crossover BABE Studies acfalcao 2007-09-16 22:34 [Design Issues]
- Three-way crossover example data set Helmut 2007-09-17 20:47
  - Three-way crossover example data set acfalcao 2007-09-17 23:02
    - Three-way crossover example data set Helmut 2007-09-18 12:47
      - Three-way crossover (WinNonlin) Nirali 2007-09-21 06:49
        
        Three-way crossover (WinNonlin) Helmut 2007-09-21 13:04
        
        Three-way crossover (WinNonlin) Nirali 2007-09-25 08:05
        
        Three-way crossover (WinNonlin) Helmut 2007-09-25 13:15
      - Three-way crossover example data set Irene_I 2018-06-07 11:09
        
        Three-way crossover example data set Helmut 2018-06-07 13:04
        
        Three-way crossover example data set Irene_I 2018-06-08 11:09
        Three-way crossover example data set Irene_I 2018-06-12 09:21
        
        Leave-One-Out (IBD) Helmut 2018-06-12 12:42
        
        Leave-One-Out (IBD) Irene_I 2018-06-13 05:02
        
        Impact of pooled variance (bias, CI) Helmut 2018-06-13 15:02
        
        carry (over?) d_labes 2018-06-13 15:31
  - Pseudo-periods ElAlumno 2019-03-14 23:40
    - Pseudo-periods Helmut 2019-03-15 00:47
      - Two‐at‐a‐Time analysis in R ElAlumno 2019-03-22 21:59
        
        fixed & mixed (dammit!) and a request to SASians Helmut 2019-03-23 01:03
        
        Pooled vs IBD T-R in SAS from non-SASian mittyri 2019-03-23 23:13
        
        Pooled vs IBD T-R in SAS from non-SASian Helmut 2019-03-23 23:36
        
        mixed in R mittyri 2019-03-23 23:50
        
        mixed in R (EMA B ≠ FDA) Helmut 2019-03-24 01:23
  - Williams design 3-way Brus 2021-06-09 16:48
    - Williams design 3-wayHelmut 2021-06-09 17:48
      - Williams design 3-way Brus 2021-06-10 14:33
        
        Williams design 3-way Helmut 2021-06-10 15:03
        
        Williams design 3-way vezz 2021-06-10 17:23
        
        Williams design 3-way Helmut 2021-06-10 20:14
        
        Williams design 3-way vezz 2021-06-11 09:11
        
        Williams design 3-way Brus 2021-06-11 12:19
        Williams design 3-way Relaxation 2021-06-11 12:42
        
        Period effects in general Helmut 2021-06-11 15:41
        Williams design 3-way vezz 2021-06-11 16:56