RE: WRES AND OUTLIER IDENTIFICATION/EXCLUSION

From: "Kowalski, Ken" Subject: RE: [NMusers] WRES AND OUTLIER IDENTIFICATION/EXCLUSION Date: Fri, 29 Sep 2006 12:17:45 -0400 Mats, It can be done in NONMEM...credit goes to Matt Hutmacher for figuring this out. You need to use the LIKELIHOOD or -2LL option. Here is an example of a $PRED code segment that Matt Hutmacher prepared and tested: $PRED MU=THETA(1)+ETA(1) MP=THETA(2) SIG1=THETA(3) SIG2=THETA(4) IW1=(DV-MU)/SIG1 IW2=(DV-MU)/SIG2 L1=-0.5*LOG(2*3.14159265)-LOG(SIG1)-0.5*(IW1**2) L2=-0.5*LOG(2*3.14159265)-LOG(SIG2)-0.5*(IW2**2) L=(1-MP)*EXP(L1)+MP*EXP(L2) Y=-2*LOG(L) Note that MU can be replaced with a more complex PK/PD model, MP is the mixing probability, SIG1 is the sigma for non-outliers, and SIG2 is the sigma for outliers. Regards, Ken