POSTHOC estimates

From: R.Port@dkfz-heidelberg.de (Ruediger Port) Subject: POSTHOC estimates Date: 16 Jul 1997 13:31:14 -0400 This is in reply to Baerbel Wittke's question: I think you should use data records where EVID=2 and MDV=1 for those patients where no concentration measurements are available. This will produce predicted plasma levels (under PRED) where the prediction is based on TVCL, the available covariate information, and the (fixed effects) parameters which link individual CL to the covariates. DV=0 without MDV=1 is interpreted as a real zero measurement, hence the exceedingly high POSTHOC estimates of individual CL. As I understand, no real POSTHOC estimates of individual clearance can be obtained without concentration measurements because all eta's are estimated to be zero in this case (the most likely value for eta when there is no concentration measurement that could suggest that this individual differs by something other than the covariates from a typical individual). Good luck! Ruedi Dr. R.E. Port, Dept. 0420, German Cancer Research Center P.O. Box 10 19 49, D-69009 Heidelberg phone: x49-6221 42-3385 -3347 fax: -3346 e-mail: r.port@dkfz-heidelberg.de