addition of dummy points

From: "Pravin Jadhav" pravinj@gmail.com Subject: [NMusers] addition of dummy points Date: Wed, April 20, 2005 11:33 am Dear all, I ran into a problem and looks like it has been discussed before. http://www.cognigencorp.com/nonmem/nm/99apr202004.html However, I need some solution for the same. While using ADVAN9 or ADVAN6, the addition of a few dummy points (DV=0 and MDV=1) affects the estimation results. In my model, the addition of 50 dummy points drastically changes the parameter estimates. I attribute this to the complexity of the model. Because when I ran a simple one compartment PK model using ADVAN9/6 with and w/o additional records, the results were slightly different. However, one would expect them to be identical. Increasing the complexity of the model, results in more deviation from the expectation. I need to be include dummy points for simulation purposes because the data are very sparse and thus sampled data do not give an idea of the "true" trajectory. Important to note that the estimation results are dependent on the number of dummy points added. I would like to run the estimation step using the raw dataset and perform simulations in the subsequent step. Can I do both operations in the same run(one control stream)? Basically, I plan too have two have two datasets (with and w/o dummy points). I would like to run the estimation using a dataset w/o dummy points and pass on the estimated parameters for simulation that uses rich dataset. I guess MSFO file will help me store the results of the estimation. But how do I make the simulation step to read the parameters from that file? The other option is manual editing(two step approach- estimation followed by simulation), however, I am fitting each subject one by one. Just want to know if there is any automatic option. Thank you in anticipation, Pravin