Implementation of interindividual variability in residual variance

From: "Piotrovskij, Vladimir [PRDBE]" - VPIOTROV@PRDBE.jnj.com Subject: [NMusers] Implementation of interindividual variability in residual variance Date: 2/17/2004 9:37 AM Dear NONMEM users, I am trying to implement an interidividual variability in the residual variance using an additional random effect: $ERR Y = F + EXP(ETA(.))*EPS(1) It turned out the corresponding OMEGA was not iterated, and the final estimate did not differ from the initial value. Below is an example control stream and the output illustrating the problem (Note, the actual model I work with is more complicated). Thanks in advance. Best regards, Vladimir ----------------------------------------------------------------- Vladimir Piotrovsky, Ph.D. Research Fellow, Advanced PK-PD Modeling & Simulation Global Clinical Pharmacokinetics and Clinical Pharmacology (ext. 5463/151) Johnson & Johnson Pharmaceutical Research & Development