Re: Additional predicted levels (EVID=2) changed objective function values
Hi Zheng,
My first guess is that you have a time-varying covariate in your data set, and
the way that NONMEM handles time varying covariates in the data set is that
they are kept fixed until an instantaneous change when the new record appears.
If your EVID=2 records change the interpretation of the covariate (either
carrying an observation backward or interpolating it), then an objective
function change is expected.
If you can post your control stream and a part of your data set, it would be
easier to help.
Thanks,
Bill
Quoted reply history
On Feb 15, 2016, at 5:46, "Zheng Liu"
<[email protected]<mailto:[email protected]>> wrote:
Dear NMusers,
I intended to print out more predicted levels at the time points without
observations. Therefore I inserted those lines with EVID=2 in the data set.
Surprisingly after doing so, the objective function value and the fitted
parameter values changed more or less. This should not be rational. Could
anyone explain the reason and how to avoid it? Thanks a lot in advance!
Best regards
Zheng Liu, Ph.D.
Pharmacometrician (postdoc), Melbourne Royal Children's Hospital
email: [email protected]<mailto:[email protected]>