Bioequivalence and Bioavailability Forum • Sample size: parallel ≠ 2× cross-over!

Sample size: parallel ≠ 2× cross-over! [Regulatives / Guidelines]

posted by Helmut – Vienna, Austria, 2012-01-09 17:22 (5268 d 13:22 ago) – Posting: # 7883
Views: 3,570

Dear Prashant!

❝ […] on basis of previously […] conducted study with increasing the sample size two times"?

Agree with Ohlbe’s post about the review.
I hope you did not fall into the trap of “sample size in a parallel study = 2× of a cross-over”! This often quoted rule of thumb doesn’t work since a correlation between CV_inter and CV_intra doesn’t exist. From the cross-over study you already performed calculate CV_total and base you sample size on it (see this post).

—
Dif-tor heh smusma 🖖🏼 Довге життя Україна!
Helmut Schütz

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Complete thread:

Expedited Review from IEC in case of change in study design amatewadi 2012-01-09 12:46 [Regulatives / Guidelines]
- Expedited Review from IEC in case of change in study design Ohlbe 2012-01-09 15:54
  - Expedited Review from IEC in case of change in study design amatewadi 2012-01-11 05:31
    - New trial = new opinion Ohlbe 2012-01-11 10:40
- Sample size: parallel ≠ 2× cross-over!Helmut 2012-01-09 16:22
- Expedited Review from IEC in case of change in study design drgunasakaran1 2012-01-13 17:51
  - Expedited Review from IEC in case of change in study design amatewadi 2012-01-22 14:26