Appropriate wording for a protocol [Two-Stage / GS Designs]

posted by ElMaestro  – Belgium?, 2019-09-09 21:39  – Posting: # 20565
Views: 4,220

Hello Elena777,

» 1. Should we include the information that evaluation after stage 1 completion should be performed assuming GMR=0.95?

I would do so.

» 2. Should we describe the maximum number of subjects who can be included in whole or in stage 2?

I would only put a cap on it if you can refer to simulations having done exactly so (having done so in exactly your way of capping).

» 3. Any other information that should be clearly stated in order to be accurate and to satisfy regulatory authorities?

Exact decision tree, and exact values for alphas, desired power level, and power being calculated using GMR=0.95.

» 4. What if BE criteria are met after stage 1, but estimated power is too low (e.g. 30%)?

"Too low"?
It is not a crime to be lucky. I don't see any issue. Regulators are generally not afraid of low power after results become available. This forum is a paradise for grumpy old men being adverse to post-hoc power. I used be to a reasonably happy, cheerful bloke, but then I got a profile here and quickly I went very sour if not outright angry. I blend in nicely, I think?!? :-D

I could be wrong, but...

Best regards,
ElMaestro

"Pass or fail" (D. Potvin et al., 2008)

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