CVs for untransformed data [Software]

posted by mittyri – Russia, 2017-09-03 10:41 (2398 d 00:45 ago) – Posting: # 17770
Views: 12,632

Hi Zhang Yong,

Helmut has asked a contrary question, I will just reformulate it
Why do you prefer
intrasubject CV = sqrt(Var(Residual)) / RefLSM
but not
intrasubject CV = sqrt(Var(Residual)) / TestLSM ?

Do you see the difference between CVs for untransformed and transformed data? Yes, for untransformed data you need to know some mean, for logtransformed data a variance only.
So even formula above is suspicious (see why in my previous post).
I know that Chow says Ref, but why not Test or - as Helmut suggested - weighted mean of LSMs? The later is even more reasonable.
I think devs just followed Chow here (and there is no interCV for untransformed data in the book). If you really need it you can post a request to Certara support with appropriate justification why do you need this in the next version.
By the way nobody stops you to calculate any additional parameters related to any means and variances in DataWizard, right? ;-)

Kind regards,
Mittyri

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