TDS.PSL - DIF ANALYSIS USING PARTIAL CREDIT MODEL                                                                               
          DIF DATA, TWO SAMPLES (1=Depressive, 2=Normal), 22 ITEMS                                                              
                                                                                                                                
>FILES  DFNAME='TDS.TXT';                                                                                                       
>INPUT  NIDCHAR=3, MGROUP=2, NTOTAL=22;                                                                                         
        (3A1,1X,1A1,1X,22A1)                                                                                                    
>TEST   TNAME='TDS',                                                                                                            
        ITEM=(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22),                                                        
        NBLOCK=22;                                                                                                              
>BLOCK1 REPEAT=22, NIT=1, NCAT=4, ORIGINAL=(0,1,2,3);                                                                           
>MGROUP DIF=(0,1,0,0), GNAME=('Depressive','Normal'), GCODE=('1','2');                                                          
>CALIB  LOGISTIC, PARTIAL, NQPT=25, CYCLES=(100,1,1,1,1,1), NEWTON=20,                                                          
        CRIT=0.01, POSTERIOR;                                                                                                   
>SCORE ;