Re: Modeling of inter study variability (ISV) as a third random effect level

Date: Mon, 31 May 1999 17:46:11 +0200 From: Pascal Girard <pg@upcl.univ-lyon1.fr> Subject: Re: Modeling of inter study variability (ISV) as a third random effect level Dear Lutz, Silvy Laporte has presented an implementation of such an ISV model at the last PAGE meeting in Wuppertal and a poster at ASCPT 98 in New Orleans. We have recently submitted a paper on this topic. The way you implement it does not work since at NEWIND=0, NONMEM has no information to compute random study effect except for the study that appears on the very first record of your dataset. We implemented ISV just like Mats implemented IOV. The trick is that in order to have a common ETA for every patient in one study, but different ETAs from one individual to another you have to set study number as the ID (ID=STUD) but no longer the patient identifier, create <<as many ETAs as the maximum number>> of patients in the biggest studies, then constraint all these ETAs to have the same variance. cheers, Pascal Pascal Girard ------------------------------------------------------------------- Service Pharmacologie Clinique PG@upcl.univ-lyon1.fr BP 3041,162, avenue Lacassagne Tel : +33 (0)4 78 78 57 26 69394 LYON Cedex 03 FRANCE Fax : +33 (0)4 78 78 57 19