covariates

From:"Renee Ying Hong" yinghong@pharm.usyd.edu.au Subject: [NMusers] covariates Date: Wed, September 15, 2004 8:02 pm Dear All, I noticed that there used to have a lengthy argument about including covariates into the model using stepwise addition and backward elimination. Different opinions were presented to solve the stepwise problems by introducing statistical "arts". Dr Jonsson and Mats published a nice paper where stepwise procedure were briefly discussed: unicovariate model was tried in the basic model one at a time, followed by subsequent steps of trying each parameter/covariate combination in the current model. Since I am beginner of NONMEM, those "arts" are beyond my knowledge. Could someone let me know the routine steps of stepwise/backward unicovariately which suit to the practical implement. Here is the example: Subroutine: ADVAN3 TRANS4 The covariates of CL: A, B, C The covariates of V1: A, D The covariates of V2: B, D What is the steps I should follow to find the final model? Kind Regards, Renee Ying Hong Faculty of Pharmacy University of Sydney Tel: 61 2 9036 5025 Fax: 61 2 9351 4391 E-mail: yinghong@pharm.usyd.edu.au