[NMusers] Interindividual variability in residual variance

Dear NMusers,<?xml:namespace prefix = o ns = =
"urn:schemas-microsoft-com:office:office" />

I have run in to an old problem that Vladimir once described here on the =
users net. I am trying to implement inter-individual variability in =
residual variance and the corresponding OMEGA is not being iterated. =
Usually, in Dr. Karlsson's work this error structure is implemented on a =
proportional or proportional+additive EPS model. I am wondering if my =
problem is because I am trying to implement ETA on EPS using the =
transform both sides approach as follows?

 

$ERROR

CALLFL=0

IPRED = -5

IF (F.GT.0) IPRED = LOG(F)

IRES=DV-IPRED

W=1

IWRES=IRES/W

Y = IPRED + EXP(ETA(.))*EPS(1)

 

Kindly advice...MNS

 

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From: "Piotrovskij, Vladimir [PRDBE]" - VPIOTROV_at_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

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Received on Wed Jul 11 2007 - 08:26:54 EDT