Re: Model Comparison and Viewing of Output

Dear Mats, Mark and Nick, Thanks for your response. Mats, thanks for refering to your paper which explains this issue. With regard to the second question, its true that we have plenty of tools which can filter out the observations from other type records post run. However, sometimes the output file size is very big for large simulations that it is difficult to open in programs like Excel (2003) because of row limitations. Thus, I was curious if we can specify something in the control stream a priori such that we only get observation records in the output file. That was the whole purpose of asking this question. Warm Regards Nitin Nick Holford <[EMAIL PROTECTED]> wrote: Nitin, I think Mark and Mats have given you sensible advice on your first question. The bottom line is that there are no magic numbers that are always the correct guide to the solution. Sometimes you just have to apply common sense. Your second question is more of a puzzle. Why are you wanting to do this? If you are planning to examine the NONMEM output table then almost any tool you would use should be able to filter out the records so that only the observations are left. Can you explain why you feel this simple filtering should be done by NONMEM? What are you trying to do with this table output when you have separated the observations from other event type records? Nick Nitin Mehrotra wrote: > > Dear NMusers, > > I had a couple of questions for the group members: > > 1. Model Comparison: Everything else remaining the same in a model, should a > drop in the objective function on addition of an eta, sigma or a covariance > term reflect an improvement in a model. Or comparing AICs, considering eta's > and sigma's as additional parameters a correct approach. I understand that > these decisions are rather based on multiple criterias like goodness of fit > plots, biological sense, physiological plausibility of the parameter > estimates etc. But specifically would like to know whether comparing > objective function among these models a logical approach? > > 2. Viewing Output via $TABLE option: When we do simulation using NONMEM,the > output file contains both the dosing and observation records. Is there a way > in NONMEM to specify a priori in the control stream, such that only > observation records could be obtained in the simulation output file? > > Thanks and Regards > > Nitin Mehrotra > > Nitin Mehrotra, Ph.D > Post Doctoral Research Fellow > 874 Union Avenue, Suite4.5p/5p > Department of Pharmaceutical Sciences > University of Tennessee Health Science Center > Memphis, TN, USA-38163 > 901-448-3385 (Lab) > [EMAIL PROTECTED] > > > ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ---------- > Shape Yahoo! in your own image. Join our Network Research Panel today! -- Nick Holford, Dept Pharmacology & Clinical Pharmacology University of Auckland, 85 Park Rd, Private Bag 92019, Auckland, New Zealand [EMAIL PROTECTED] tel:+64(9)373-7599x86730 fax:+64(9)373-7090 www.health.auckland.ac.nz/pharmacology/staff/nholford Nitin Mehrotra, Ph.D Post Doctoral Research Fellow 874 Union Avenue, Suite4.5p/5p Department of Pharmaceutical Sciences University of Tennessee Health Science Center Memphis, TN, USA-38163 901-448-3385 (Lab) [EMAIL PROTECTED] --------------------------------- Fussy? Opinionated? Impossible to please? Perfect. Join Yahoo!'s user panel and lay it on us.