RE: Describing variability

From:"Bachman, William" Subject:RE: [NMusers] Describing variability Date:Tue, 1 Apr 2003 11:23:16 -0500 Ken, While those are all certainly good suggestions (and I highly recommend them), there are still some relatively simple models (read as not over-parameterized) where you won't get a successful $COV (e.g when sampling is limited and there is just no way you're going to get any more or better data, like pediatric studies.) Should you not use the model for any purpose? I don't think so. It may still be adequate for descriptive purposes or planning of further studies. $COV is a bonus in that it gives you added confidence that you have not found a local minimum (as well as estimates of the standard errors, etc). If the situation warrants, certainly take a Bayesian approach or do extensive simulation studies, but I don't think that's ALWAYS necessary, do you? You have implied that I don't think successful convergence or $COV is ever needed or desired. The point I'm trying to make is that some sort of balanced approach can be taken and sometimes, you have to "go with what you got." Bill