RE: BOV
From: Michael.J.Fossler@gsk.com
Subject: RE: [NMusers] BOV
Date: Wed, September 22, 2004 1:19 pm
Can we clarify what is meant by "occasion"? In Yaning's example, occasion
(as I understand it - a point in time when some measurement is made) is
confounded by site (in other words, hospital). Given Yaning's proposed
experimental design, I don't think any model would be satisfactory, since
there is no way to tease out the effect of site (hospital) from the effect
of occasion. A better design would be
i = subject (1-4)
j = site (1-4)
Sub1 Sub2 Sub3 Sub4
Occ1 CL11 CL22 CL33 CL44
Occ2 CL14 CL21 CL32 CL43
Occ3 CL13 CL24 CL31 CL42
Occ4 CL12 CL23 CL34 CL41
Mean CLavg1 CLavg2 CLavg3 CLavg4
Here site and occasion are no longer confounded, and a true BOV
(controlled for site) could be estimated.
Mike
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Michael J. Fossler, Pharm. D., Ph. D., F.C.P.
Principal Clinical Pharmacokineticist
Clinical Pharmacokinetics, Modeling & Simulation
GlaxoSmithKline
(610) 270 - 4797
FAX: (610) 270-5598
Cell: (443) 350-1194
Michael_J_Fossler@gsk.com
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~