Re: 1 binary response/person

From: Nick Holford <n.holford@auckland.ac.nz> Subject: Re: 1 binary response/person Date: Tue, 18 Sep 2001 07:19:57 +1200 Lewis, Would you please confirm that your comments about OMEGA being meaningless are restricted to the single binary response per person case? How exactly do you know they are meaningless? Is your assertion that they are meaningless based on theoretical considerations or on the results of simulation? Are your comments about the precision of estimates from hierarchical vs non-hierarchical methods based on (misguided) attempts to estimate OMEGA or in the case where OMEGA is fixed to zero? What is your opinion/experience of the meaningfulness of OMEGA estimates for repeated measures binary responses? I am not familiar with other non-hierarchical methods for logistic regression. Do they exist for repeated measures? The key advantages of using NONMEM for binary and other categorical responses is that one is not restricted to estimating parameters of linear (or linearized) models and one can perform joint estimation of PK parameters with the PK predictions driving the model for the binary response. And of course given a hammer everything looks like a nail. Nick -- Nick Holford, Divn Pharmacology & Clinical Pharmacology University of Auckland, 85 Park Rd, Private Bag 92019, Auckland, New Zealand email:n.holford@auckland.ac.nz tel:+64(9)373-7599x6730 fax:373-7556 http://www.phm.auckland.ac.nz/Staff/NHolford/nholford.htm