RE: if-the-statement for 3 class categorical covariate

Dear Bernard, If you want to model the effect of a 4 categorical covariate (genotype) on CL I would try the following code: ;3 dummy categories because you have one covariate of 4 categories.UG1=0UG2=0UG3=0 ;Reference category [I have supposed TT (GENE.EQ.1)]IF (GENE.EQ.2) UG1=1 ;GTIF (GENE.EQ.3) UG2=1 ;GGIF (GENE.EQ.4) UG3=1 ;MISSING MU1 = LOG(THETA(1)*(THETA(2)**UG1*THETA(3)**UG2*THETA(4)**UG3)) CL = EXP(MU_1+ETA(1)) Hope it helps. On the other hand, why do you use a different ETA for each category of the genotype variable? Best regards. Mario > Date: Thu, 25 Jul 2013 07:08:32 -0700 > Subject: [NMusers] if-the-statement for 3 class categorical covariate > From: [email protected] > To: [email protected] > > Dear all > > I am shoked because NONMEM sents a crash message when i factor in > covariate modeling using a 4 class categorical variable genotype: > IF (GENE.EQ.3) THEN ;GG > CL = THETA(1)* EXP(ETA(1)) > ELSE IF (GENE.EQ.2)THEN ;GT > CL = THETA(6)* EXP(ETA(3)) > IF (GENE.EQ.1) THEN ;TT > CL = THETA(7)* EXP(ETA(4)) > IF (GENE.EQ.4) THEN ;MISSING > CL = THETA(7)* EXP(ETA(4)) > END IF > However if i binarize the code, nonmem runs successfully > IF (GENE.EQ.3) THEN > CL = THETA(1)* EXP(ETA(1)) > ELSE > CL = THETA(6)* EXP(ETA(3)) > > END IF > > Thanks in advance > -- > Bernard Ngara > Trainee Biostatistician > Africa Institute of Biomedical Science and Technology > P. O Box 2294 > Harare > Zimbabwe > +263 772 160 896