Hi,
This problem was discussed before on NMUSERS, here's a link with code suggested by Leonid Gibiansky and Mats Karlsson (code allowing for a combined - additive and proportional error in log space): http://www.cognigencorp.com/nonmem/nm/98may202004.html You model the log transformed data - so the DV is actually log concentration. You estimate in linear space and log transform the estimated concentrations when you define the Y as in the code in the link above. Regards, Andrzej Andrzej Bienczak MSc, MPharm, DiplPharm Pharmacometrics Group Division of Clinical Pharmacology Department of Medicine University of Cape Town K45 Old Main Building Groote Schuur Hospital Observatory, Cape Town 7925 South Africa phone: +27 21 650 4861 mobile: +27 839 842 675 email: andrzej.bienc...@gmail.com <mailto:andrzej.bienc...@gmail.com> From: owner-nmus...@globomaxnm.com [mailto:owner-nmus...@globomaxnm.com] On Behalf Of Katrin Volz Sent: 16 December 2016 11:35 AM To: nmusers@globomaxnm.com Subject: [NMusers] $Error log transformed Dear All, I would like to model my data log transformed. So far, I already found some suggestions for this problem here but none of them worked in my case - probably I did sth. wrong. I would be very happy if someone could help me with changing my error model, which I assume has to be changed. (I also assume that the dataset has to be changed from DV to LOG(DV)?) So, here is the code I used so far (not log transformed): $ERROR IPRED = F ;IPRED drug in the central compartment IF (CMT.EQ.5) IPRED = A(5) ;IPRED second drug in 5th compartment DEL=0 IF (IPRED.EQ.0) DEL=0.0001 W = F IRES = DV - IPRED IWRES = IRES /(W + DEL) Y = IPRED + IPRED * EPS(1) ; error drug in the central compartment IF (CMT.EQ.5) Y = IPRED + IPRED * EPS(2) ; error second drug in 5th compartment It would be great to get some help. Thanks! Katrin
