RE: Placebo-corrected PD models

From:"Hu, Chuanpu" Subject:RE: [NMusers] Placebo-corrected PD models Date:Fri, 17 May 2002 09:45:50 -0400 Daren/Leonid, The issue seems to be deciding whether to model, in Daren's term, R1 or R2. By definition, although the likehood L(theta | data) depends both on parameters theta and the data, it is meant to be used to choose the parameters, not data, because data are given. However, you may discard any data you deem irrelevent for your modeling purpose. In other words, the decision is subjective and cannot be formally based on data. It does not seem that Leonid's model 2 is equivalent to Daren's R2 because Log(Response(0)/Placebo(0)) is model prediction in model 2, however it is observation in R2. Chuanpu -------------------------------------------------------------------------- Chuanpu Hu, Ph.D. Research Modeling and Simulation Clinical Pharmacology Discovery Medicine GlaxoSmithKline Tel: 919-483-8205 Fax: 919-483-6380