more on PREDvsDV

From: "Bonate, Peter, Quintiles" <pbonate@qkcm.quintiles.com> Subject: more on PREDvsDV Date: Tue, 2 Feb 1999 07:37:10 -0600 In my mind, the choice of whether to plot Pred vs. DV or DV vs Pred is really quite arbitrary. I believe that the use of Pred vs. DV is common practice because then one can then plot a regression line using DV as the independent variable and Pred as the dependent variable. But it must be kept in mind that any regression line (whether it is least squares, loess, etc.) between these two variables is an artifact because however you plot them, they are both subject to error. Thus, the regression coefficient will be attenuated compared to the true value of the slope. A more proper method would be to use an error-in-variables regression, such as simulation extrapolation or maximum likelihood. PETER L. BONATE, PhD. Clinical Pharmacokinetics Quintiles POB 9627 (F4-M3112) Kansas City, MO 64134 phone: 816-966-3723 fax: 816-966-6999