FDA loves SAS code? [R for BE/BA]

posted by d_labes  – Berlin, Germany, 2009-04-23 09:48 (4656 d 13:07 ago) – Posting: # 3588
Views: 64,747

Dear Yung-jin,

where does the code come from?
I cannot find it in Jones / Kenward.
And sorry it does not work for me :-(
(Syntax errors in the random statement! Maybe there is something missing, Intercept or sub(seq)?).

And if you have working code, please guide me to the different intra-subject variabilities (resulting always from the SAS REPEATED statement) in the results from bear's lme() statement.
Up to now I have not found any equivalent in bear's output.

And what about the DDFM=blabla? I have learned so far (in reading tons of Web sites) that there is no such thing as different denominator degrees of freedom methods in lme()? I had been informed further, that the successor of lme() - lmer() - does not give any DenDF and p-values for the effects in the model (fixed or random) by design, because the inventor and developer D. Bates does not belief that the test statistics follow any of the usually applied distribution (F distr.). See here f.i. A consequent but strange countenance.
Since SAS Proc MIXED uses these DDFM also in calculation of CI's for the treatment effect, there must be any difference.

BTW: Kenward/Jones in their Proc MIXED code always use DDFM=KR, i.e. the Kenward/Roger method. Not so astonishing I think :-D .

BTW2: Let me state explicitly that these discussions are not for proving you / bear wrong.
I am seriously on the way to change "The power to know" to R, but only if I can fulfill the needs in statistics for bioequivalence studies (regulators bullet proof), my everyday bread and butter work.
And currently I suspect that this is not feasible for replicate studies.
Or is anybody out there to prove me that black is white?
Anybody out there who has evaluated a replicate study with R (not necessarily bear) which was approved by a regulatory agency?



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