Non inferiority Margin without Placebo controlled Trial

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Blockquote
How to estimate the Non inferiority Margin/Equivalence Margin if we do not have Placebo controlled Trial.

There seems to be a distinction between a “non-inferiority” trial (where the control is a treatment presumed to be effective), and an efficacy trial, that is compared to placebo (presumed to be inert).

The following has a nice chart that elaborates on the distinction.

The regions and the frequentist procedure to provide evidence against the default:

  1. Noninferiority – .One sided test against lower bound of effect size of interest.
  2. Equivalence – TOST (Two one-sided tests).
  3. Efficacy – Two Sided conventional test against effect of exactly 0.

I do think the Bayesian intervals or Jeffrey Blume’s interval intersection procedure are interesting alternatives.

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