Deficiencies [Power / Sample Size]

posted by Helmut Homepage – Vienna, Austria, 2018-02-01 16:48 (2327 d 12:49 ago) – Posting: # 18323
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Dear Detlew,

❝ Also you may be correct I must confess that I seldom or never had done this alpha-adjustment in case I used a higher order design. Reasons:

Never had problems with using un-adjusted alpha :cool: in more then 30 years.

I faced two.
  1. In a dose-linearity study (two adjusted doses compared to one – i.e., not proportionality by the power model). Very similar to the example by Hauschke et al. in chapter 7.4.1 where we find:

    “… for a joint decision rule where all requirements must be fulfilled, no adjustment of the comparisonwise type I error is needed to keep the familywise type I error under control.”

    Received a deficiency letter from the BfArM in 2005 asking for adjustment:

    “Aufgrund der multiplen Berechnung (2 Testpräparate) sollte das Bonferroni-adjustierte 95% Konfidenzintervall […] des Referenzproduktes angenommen werden.”

  2. One of my clients aimed at showing BE of two products (tablet, capsule) vs. the reference. One passed and the other one failed. Only the passing one was submitted. Received a deficiency this year from an undisclosed agency:

    “Please provide a statistical analysis with proper alpha-adjustment […] as we are of the opinion, that alpha-adjustment is required for this design.”

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