Geometric means and adjusted means (LSMs) [General Sta­tis­tics]

posted by Helmut Homepage – Vienna, Austria, 2018-07-26 15:38 (904 d 01:47 ago) – Posting: # 19106
Views: 3,695

Hi Russel,

» […] do you recommend showing the geometric means along with the adjusted geometric means (from ls means) and the ratio from the adjusted in a single table? Or it does not make sense to even include the geometric means. My initial thought it would be good to include both just to see if the adjustments from the model. But it may cause confusion and may not be worth it. :confused:

Well, that’s a matter of taste. I mainly deal with European submissions where the tables mentioned in Appendix IV of the BE-GL are mandatory (see esp. Table 3.1). Never give the arithmetic means (we know that AUC and Cmax follow a log-normal distribution) but the geometric means ±CV%. I tried to convince the EMA to use only the geometric least squares means (see there) but didn’t succeed.

Geometric means are fine to represent the outcome of subjects under each treatment. In the synopsis of my statistical reports I always give xgeo ± CV%. Only if the study was unbalanced (or a parallel design with unequal group sizes) I give additionally the GLSM ± SD (together with a footnote clarifying why they are different). That’s like you would do.
Never got a request for clarification from any agency (either the assessors were clever or the footnote helped). ;-)

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Helmut Schütz

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