Idential sampling points result in different RSE. Is this a bug or normal?

[Mike-Hood]

Hi Andrewhooker ,

I am new to this tool. I found:

Only one time point at the time 1 hour:

Two time points at the time 1 hour:

The bpop[2] is quite different. I am wondering how this happens.

Thank you,

Mike

[Andrew Hooker]

Hi

If you take two samples at the same time point then (assuming that there is no correlation between samples ... as is common in PKPD models) taking 2 samples will give twice as much information as 1 sample. See for example Nyberg, J., Hoglund, R., Bergstrand, M., Karlsson, M. O. and Hooker, A. C. (2012) ‘Serial correlation in optimal design for nonlinear mixed effects models’, J Pharmacokinet Pharmacodyn, 39(3), pp. 239–249. doi: 10.1007/s10928-012-9245-5.

Best regards,
Andrew