RE: Describing variability

From: "Bachman, William" Subject: RE: [NMusers] Describing variability Date:Wed, 2 Apr 2003 11:27:35 -0500 I respectfully disagree with 1. and 2. There will be times when it is appropriate to use a model that has: a. terminated due to rounding errors b. converged but not given a successful $COV step (there are instances when the model is NOT problematic at all, yet NONMEM will not give a $COV so here is where you argument falls apart). I will try to find a concrete example. This is just the facts of NONMEM as it exists today so your statistical arguments don't apply. I think it's a good idea to formalize the thought process to some degree. On the other hand you're reducing the process to a set of RULES that are not really hard and fast as you seem to think. I'm glad we stimulated discussion on the subject but I think we're far from a conscensus by any means. What I do agree with is Leonid's "common sense" approach (with the exception of variance estimates within 30-40%, there is no basis for this.) Bill