Dear NM Users,

I have a question regarding EVID=2 and the covariance step. I am fitting a 
tumor growth inhibition model to my data and I am still at the beginning where 
I am using a base model (no covariates). I have time changing covariates in the 
dataset which I am working with, some of which were measured at time points 
which do not coincide with the DV observations and hence I used EVID=2.

When I first run the model (FOCE+I), I got very high relative standard errors 
for the parameter estimates. However when I duplicated the control stream with 
just one change : IGNORE=(EVID.EQ.2), I got exactly the same OFV and the same 
parameter estimates (this is obvious since I have not included any of the 
covariates), but with dramatically lower relative standard errors.

Do you have an explanation for what may have went wrong ?
(by the way, I used FO just for testing and in both cases the RSEs were exactly 
the same).

Best Regards,

Ahmed Abbas Suleiman, MSc
PhD Candidate at Bonn University
Institute of Pharmacology - Clinical Pharmacology Unit
Hospital of the University of Cologne
Gleueler Str. 24, 50931 Cologne,
Germany
Phone: +49-(0)-221-478-3402

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