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RE: How $simulation work with $estimation

From: Elodie Plan <elodie.plan>
Date: Wed, 15 Oct 2008 01:45:44 +0200

Dear Jun,


When $SIM and $EST on the same model file, the simulation will be run first,
based on initial values, and then, afterwards, the estimation of the
simulated data will be done, that's it, no further re-simulation based on
the estimated parameters will follow.

So what you should do is first to analyze your observed data in an
estimation model file, and then report your estimated parameters as initial
values to run your simulation-estimation study; this allows you to compare
estimates of real data to estimates of simulated data, so to check
simulation properties of your model.


I hope this helps,



             Elodie Plan, PharmD, MSc,



Div. of Pharmacokinetics and Drug Therapy,
 Department of Pharmaceutical Biosciences,
  Faculty of Pharmacy, Uppsala University

  PO - Box 591 - 751 24 Uppsala - SWEDEN

Office +46 18 4714385 - Fax +46 18 4714003


From: owner-nmusers
Behalf Of Jun Shen
Sent: Wednesday, October 15, 2008 1:01 AM
To: nmusers
Subject: [NMusers] How $simulation work with $estimation


Dear NMusers,

I wonder how does $Simulation work with $Estimation in NONMEM exactly?
The manual says, NONMEM will simulate DVs and replace the original DVs
based on the parameter initial values. But the initial values are not final
estimates. Does the simulation based on initial values make sense? Do
$Estimation and $Simulation run alternatively? The $Simulation generates a
set of data based on which the parameters are estimated? And then the
predictions are made on the estimated parameters? A little confused.

Appreciate any comment.


Received on Tue Oct 14 2008 - 19:45:44 EDT

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