Re: PRED VS WRES
From: Lewis B Sheiner <lewis@c255.ucsf.edu>
Subject: Re: PRED VS WRES
Date: Fri, 27 Jul 2001 12:32:43 -0700
WRES tends to be diagnostic for the within-individual (i.e PK) model.
If by "S shape trend" you mean that the residuals follow a trend to be
first >0 and then <0, then this suggests that you need to further
elaborate your PK structural model (e.g., a 2 compartment model instead
of a 1-compartment model).
And if this were so, it would make sense that it would be seen most readily with
the IV
data rather than with dosage forms exhibiting slower absorption.
A better plot, in my opinion, for diagnosing the adequacy of
the subject-specific mdoel is IPRED vs IWRES.
--
_/ _/ _/_/ _/_/_/ _/_/_/ Lewis B Sheiner, MD (lewis@c255.ucsf.edu)
_/ _/ _/ _/_ _/_/ Professor: Lab. Med., Biophmct. Sci., Med.
_/ _/ _/ _/ _/ Box 0626, UCSF, SF, CA, 94143-0626
_/_/ _/_/ _/_/_/ _/ 415-476-1965 (v), 415-476-2796 (fax)