Does not calculate Stderr, CV, CI in a 2 compartment model

Phoenix Certara Forums Modelling and Simulation
1

Hi all,

I am running some data using a 1 compartment or a 2 compartment models un PopPK module with a FOCE ELS algorithm. However, when I get the theta values they lack the CV%, the CI and the Stderr values while they are returned with the 1 compartment model. If I choose to run the QRPEM algorithm, then all those parameters and calculated for both models.

  1. Is there a reason why I cannot get the CV, CI, etc with the FOCE ELS for 2 compartment model?
  2. In order to choose between both models, would AIC be affected whether FOCE ELS or QRPEM algorithms are used (for both)?

Thanks

Ignacio

2

Hi Ignacio, we had a similar discussion here,

https://support.certara.com/forums/topic/1037-missing-stderr-cv-and-ci-from-theta/?p=4494

you can also try to accept all your final estimates and then re-execute FOCE-ELS, sometimes you will get SE’s then.

Regarding your AIC question, the maximum value of the likelihood function for the model will probably be different between the two algorithms, so I although this may guide you, i don’t think you can use it as quantitative proof when comparing across different model engines.

Simon