From:  Nick Holford 
Subject:[NMusers] Correction to 1999 posting on between occasion variability
Date:Tue, 13 May 2003 08:33:09 +1200

An observant colleague pointed out an error in NM-TRAN abbreviated code I sent to NMUSERS
in 1999 describing how to implement between occasion variability (BOV) (also known as
inter occasion variability (IOV)).


http://www.cognigencorp.com/nonmem/nm/94nov171999.html


The ETA() index for the BSV random effect was incorrect. A corrected (and more flexible
code) is shown below. I have re-ordered the OMEGA for BSV so that adding BOV for
additional occasions would not require this random effect ETA to be re-numbered.

$INPUT TIME OCC AMT DV 

$THETA 1 ; CL

$OMEGA .5 ; BSVCL
$OMEGA BLOCK(1) .25 ;Occ 1
$OMEGA BLOCK(1) SAME ;Occ 2
; Repeat the $OMEGA BLOCK(1) SAME record for each occasion after the first

$PK

BSV=ETA(1)

IF (OCC.EQ.1) THEN
BOV=ETA(2)
ENDIF
IF (OCC.EQ.2) THEN
BOV=ETA(3)
ENDIF
; Repeat above IF/ENDIF block for each occasion


CL=THETA(1)*EXP(BSV+BOV)

Apologies for any confusion this may has caused.

Nick

--
Nick Holford, Dept Pharmacology & Clinical Pharmacology
University of Auckland, 85 Park Rd, Private Bag 92019, Auckland, New Zealand
email:n.holford@auckland.ac.nz tel:+64(9)373-7599x86730 fax:373-7556

http://www.health.auckland.ac.nz/pharmacology/staff/nholford/


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