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. 2017 Jun 15;25(2):93–100. doi: 10.12793/tcp.2017.25.2.93

Table 2. Ten models for data in Table 1.

Model No. Description SAS Script
1 Independent two-group t-test PROC TTEST
 DIST=LOGNORMAL ALPHA=0.1;
 CLASS TRT2;
 VAR CMAX;
2 Conventional 2×2 model PROC GLM;
 CLASS SEQ PRD TRT SUBJ;
 MODEL LNCMAX = SEQ SUBJ(SEQ) PRD TRT;
 RANDOM SUBJ(SEQ) / TEST;
 LSMEANS TRT /PDIFF=CONTROL('R') CL ALPHA=0.1;
3A Full model with ADM as fixed factor and PRD nested within ADM PROC GLM;
 CLASS ADM SEQ PRD TRT SUBJ;
 MODEL LNCMAX = ADM SEQ(ADM) SUBJ(ADM*SEQ) PRD(ADM) ADM*TRT TRT;
 RANDOM SUBJ(ADM*SEQ) / TEST;
 LSMEANS TRT /PDIFF=CONTROL('R') CL ALPHA=0.1;
3B Reduced model of 3A remov- ing ADM*TRT PROC GLM;
 CLASS ADM SEQ PRD TRT SUBJ;
 MODEL LNCMAX = ADM SEQ(ADM) SUBJ(ADM*SEQ) PRD(ADM) TRT;
 RANDOM SUBJ(ADM*SEQ) / TEST;
 LSMEANS TRT /PDIFF=CONTROL('R') CL ALPHA=0.1;
4A Full model with ADM as fixed factor and PRD not nested PROC GLM;
 CLASS ADM SEQ PRD TRT SUBJ;
 MODEL LNCMAX = ADM SEQ(ADM) SUBJ(ADM*SEQ) PRD ADM*TRT TRT;
 RANDOM SUBJ(ADM*SEQ) / TEST;
 LSMEANS TRT /PDIFF=CONTROL('R') CL ALPHA=0.1;
4B Reduced model of 4A removing ADM*TRT PROC GLM;
 CLASS ADM SEQ PRD TRT SUBJ;
 MODEL LNCMAX = ADM SEQ(ADM) SUBJ(ADM*SEQ) PRD TRT;
 RANDOM SUBJ(ADM*SEQ) / TEST;
 LSMEANS TRT /PDIFF=CONTROL('R') CL ALPHA=0.1;
5A Full model with ADM as random factor and PRD nested within ADM PROC MIXED;
 CLASS ADM SEQ TRT SUBJ PRD;
 MODEL LNCMAX = SEQ(ADM) PRD(ADM) TRT;
 RANDOM ADM SUBJ(ADM*SEQ) ADM*TRT;
 ESTIMATE 'T VS R' TRT -1 1 / CL ALPHA=0.1;
5B Reduced model of 5A removing ADM*TRT PROC MIXED;
 CLASS ADM SEQ TRT SUBJ PRD;
 MODEL LNCMAX = SEQ(ADM) PRD(ADM) TRT;
 RANDOM ADM SUBJ(ADM*SEQ);
 ESTIMATE 'T VS R' TRT -1 1 / CL ALPHA=0.1;
6A Full model with ADM as random factor and PRD not nested PROC MIXED;
 CLASS ADM SEQ TRT SUBJ PRD;
 MODEL LNCMAX = SEQ(ADM) PRD TRT;
 RANDOM ADM SUBJ(ADM*SEQ) ADM*TRT;
 ESTIMATE 'T VS R' TRT -1 1 / CL ALPHA=0.1;
6B Reduced model of 6A removing ADM*TRT PROC MIXED;
 CLASS ADM SEQ TRT SUBJ PRD;
 MODEL LNCMAX = SEQ(ADM) PRD TRT;
 RANDOM ADM SUBJ(ADM*SEQ);
 ESTIMATE 'T VS R' TRT -1 1 / CL ALPHA=0.1;

ADM, hospitalization and drug administration group code (1, 2, or 3); SEQ, treatment sequence group (RT, reference then test treatment; TR, test then reference treatment); PRD, period (1 or 2); TRT, treatment (T, test treatment; R, reference treatment); SUBJ, subject ID; LNCMAX, maximum concentration (Cmax) value in natural log scale.