RE: WRES vs. time

From: "Mats Karlsson" mats.karlsson@farmbio.uu.se Subject: RE: [NMusers] WRES vs. time Date: Thu, September 2, 2004 1:18 am Toufigh, I agree with what has been suggested before. Just one additional point. There may be nothing wrong with your model but with you diagnostic plot. WRES is the "perfect" residual to inspect when we use the first-order (FO) method as there is a direct correspondence between the estimation method and the residual. However, not so when we use conditional estimation methods (FOCE, FOCE INTER), but we still use it lacking anything better. We often take it for granted that diagnostic plots should show no pattern (or a particular pattern similar for all applications). This is often not the case. I suggest that you take you final parameter estimates and your study design (realized doses and sampling times), simulate new data and obtained predictions and WRES (in one go using $SIML and $EST MAXEVAL=0). If the pattern then is similar to what you saw with real data, I would be satisfied that the WRES pattern is no concern. Best regards, Mats -- Mats Karlsson, PhD Professor of Pharmacometrics Div. of Pharmacokinetics and Drug Therapy Dept. of Pharmaceutical Biosciences Faculty of Pharmacy Uppsala University Box 591 SE-751 24 Uppsala Sweden phone +46 18 471 4105 fax +46 18 471 4003 mats.karlsson@farmbio.uu.se _______________________________________________________