Bioequivalence and Bioavailability Forum • Paired design

Paired design [Power / Sample Size]

posted by Helmut – Vienna, Austria, 2014-10-02 15:43 (4288 d 13:58 ago) – Posting: # 13644
Views: 15,374

My Capt’n,

sorry to interfere.

❝ in either case we'd be working on y=Blah+e

❝ where Blah has two levels (Before and after, or Test and Reference), leaving out other fixed stuff here because it doesn't affect power.

In your OP you wrote about a 222 design – which has period+sequence in the model. The only application of paired designs I know of (in BA, not BE) are ones where you compare PK metrics in steady state to single dose (e.g., AUC_τ to AUC_∞ in order to assess deviation from linear PK). Naturally we have not sequence here (MD always after SD) and have to assume no period effect.

Edit: Due to +1 df, the paired model is always more powerful than the cross-over.

library(PowerTOST)

known.designs()[c(3, 12), ]


    no design  df df2 steps bk bknif bkni            name

3    1  2x2x2 n-2 n-2     2  2   1/2  0.5 2x2x2 crossover

12 100 paired n-1 n-1     1  2   2/1  2.0    paired means



power.TOST(CV=0.2, n=18, design="2x2x2")

[1] 0.7912399

power.TOST(CV=0.2, n=18, design="paired")

[1] 0.793409

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Complete thread:

Proc power ElMaestro 2014-09-30 11:23
- Proc power d_labes 2014-10-01 09:26
- Proc power jag009 2014-10-01 20:55
  - screen shot ElMaestro 2014-10-01 21:02
    - Paired design d_labes 2014-10-02 13:00
      - Paired design ElMaestro 2014-10-02 13:33
        
        Paired designHelmut 2014-10-02 13:43
        
        Paired design nobody 2014-10-02 14:00
        Paired design ElMaestro 2014-10-02 14:25
        
        A wee little hole in the coconut ElMaestro 2014-10-04 18:13
        
        A wee little hole in the coconut Helmut 2014-10-04 19:23
        
        Paired design Ben 2014-10-05 10:43
        
        Paired design ElMaestro 2014-10-05 14:01