## Questions on understanding the 4-way RSABE method SAS code [RSABE / ABEL]

Hi Winnie,

❝ I am a new learner and I am trying on understanding the 4-way RSABE method SAS code provided by FDA: […]

❝ I found some discussion about the S2wr and it is really helpful to me. About the ilat, my understanding is that the model is a simple linear model and the estimate is the least square mean.

I don’t speak SAS but isn’t it a restricted maximum likelihood estimate?

❝ My R code example is as follows: […]

I’m short in time right now; compare it to Detlew’s script in base R.

❝ My question is 1) how to interpret x and critbound=(x+y)+sqrt(((boundx-x)**2)+((boundy-y)**2))? Is there any related explanation about them?

Haha, ‘the unknown x’.  I’m aware of only one reference,* which is – regrettably – not in the public domain.
• The statistical approach we use is very similar to that proposed by Tothfalusi,
Endrenyi, et al. 2001, with a minor difference (use of an unbiased estimator for
(μTμR)2).

• Schuirmann D. U.S. FDA Perspective: Statistical Aspects of OGD’s Approach to Bioequivalence (BE) As­sess­ment for Highly Variable Drugs. Presentation at the 2nd conference of The Global Harmonisation Ini­ti­a­tive (GBHI). Rockville. September 15–16, 2016.

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

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