NONMEM Users Network Archive

Hosted by Cognigen

Re: computation of exponential error model for RUV

From: Jakob Ribbing <jakob.ribbing>
Date: Mon, 19 Jul 2021 18:03:15 +0200

Dear Monia,

Yes, that is correct.
So if one were to use this parameterization for FOCE then one would effecti=
vely get a proportional (symmetric) error distribution, exactly according t=
o what you suggested:

For this reason, the standard approach in NONMEM (for FOCE and exponential =
RUV), is to log-transform both sides, this:

So additive on the log-transformed scale is exactly the error model you wou=
ld like to use.
Maybe that would be a solution for your comparison?

Best wishes


> On 19 Jul 2021, at 17:34, Guidi Monia <Monia.Guidi
> Dear colleagues,
> We would like to compare the NONMEM predictions with those obtained by a =
Bayesian TDM software for models describing the residual unexplained variab=
ility with exponential errors.
> We need to know if NONMEM performs a first order Taylor expansion of the =
exponential error when data are fitted by the FOCE method:
> Y=F*EXP(EPS(1)) -> Y= F*(1+EPS(1)).
> Could someone help with this?
> Thanks in advance
> Monia
> Monia Guidi, PhD
> Pharmacometrician
> Service of Clinical Pharmacology | University Hospital and University of =
> Center of research and innovation in Clinical Pharmaceutical Sciences | U=
niversity Hospital and University of Lausanne
> BU17 01/193
> CH-1011 Lausanne
> email: monia.guidi
> tel: +41 21 314 38 97
> centre hospitalier universitaire vaudois
> <image001.png>

*This communication is confidential and is only intended for the use of the=
individual or entity to which it is directed. It may contain information
that is privileged and exempt from disclosure under applicable law. If you=
are not the intended recipient please notify us immediately. Please do not=
copy it or disclose its contents to any other person.*

*Any personal data
will be processed in accordance with Pharmetheus' privacy notice, available=
here <>.**

Received on Mon Jul 19 2021 - 12:03:15 EDT

The NONMEM Users Network is maintained by ICON plc. Requests to subscribe to the network should be sent to:

Once subscribed, you may contribute to the discussion by emailing: