SAS vs. SAS [RSABE / ABEL]

posted by d_labes  – Berlin, Germany, 2013-04-23 16:50 (2984 d 07:12 ago) – Posting: # 10475
Views: 18,426

Hi Shuanghe,

» Now, my average BE gives:
» PE: 1.01021, same as John's :yes:
» 90% CI: 80.7733 - 126.3450, different from both of yours. :no:
» Weird.

don't worry. My results (using Johns code for ABE as given above at start of the thread) under SAS9.2 are:
  point est.  90% confidence interval
  101.0213%     80.7733   126.3450
  s2wR = 0.4210 -> CVwR = 72.35%

Deleting the 4 subjects with missings (same happens in the intra-subject contrast calculations) gives
  point est.  90% confidence interval
  90.5032%     73.5627   111.3449
  s2wR = 0.4001 -> CVwR = 70.14%

very similar to the numbers used for the RSABE criterion :cool:.

But I don't believe in this numbers anyway. I think the optimizer stops here arbitrarily as almost ever for a partial replicate design in which the intra-individual variability for T is not identifiable.
Any modification to the code, f.i. fitting a model with no subject-by-treatment interaction via the CS covariance structure crashes with infinite likelihood and an estimate of s2wT=0!

I always wondered why the FDA insists on the Proc MIXED code, especially for that design.
On the other hand in the context of RSABE linearized criterion the point estimator and its 90% CI are calculated via intra-subject contrast T-R.
Why not use these results for ABE also :confused:.

To increase the confusion here the results of the mighty oracle EMA code (same Proc GLM as for a 2x2 crossover for the PE and CI, s2wR from analysis of data for R (B) only):
  point est.  90% confidence interval
  98.4476%     78.6492   123.2298
  s2wR = 0.39824522 -> CVwR = 69.94%


So much numbers to choose between :-D.

Regards,

Detlew

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