all  104
open data Mlogitdata.wk1
data(format=wk1,org=obs) /

*table

set ag = %if(age.eq.3.,1.,0.)           ; * 1->old       0->young
set SECT = %if(sector.eq.3.,1.,0.)      ; * 1->industry  0->service+trade
set EDU = %if(EDUC.eq.4.,1.,0.)         ; * 1->postgrad  0->university
set GEND = %if(GENDER.eq.2.,1.,0.)      ; * 1->MALE      0->FEMALE

SET VAR = A4  ; * THIS IS WHERE WE COPY THE ITEM I.E. DEPENDENT VARIABLE
SET X1 = AG
SET X2 = GEND
SET X3 = SECT


set Y1 = %if(VAR.eq.3.,1.,0.)                   ; * 1->AVERAGE   0->OTHER
set Y2 = %if(VAR.eq.4..OR.VAR.eq.5.,1.,0.)      ; * 1->HIGH      0->OTHER
set Y0 = 1.0-Y1-Y2                              ; * 1->LOW       0->OTHER


NONLIN B10 B11 B12 B13 B20 B21 B22 B23
COMP B10=-2.,B20=-15.,B11=-40.,B12=-0.1,B13=10.,B21=120.,B22=10.,B23=10.

FRML EQ  = B10+B11*X1+B12*X2+B13*X3
FRML EQQ = B20+B21*X1+B22*X2+B23*X3
FRML P1 = EXP(EQ)/(1.+EXP(EQ)+EXP(EQQ))
FRML P2 = EXP(EQQ)/(1.+EXP(EQ)+EXP(EQQ))

FRML LOGL = Y1*LOG(P1)  + Y2*LOG(P2) + Y0*LOG(1.0000001-P1-P2)       ;* 1.0000001 is to avoid a crash

MAXIMIZE(TRACE,METHOD=SIMPLEX,ITERS=5,PRINT) LOGL 1 *
MAXIMIZE(TRACE,METHOD=BFGS,ROBUST,RECURSIVE,ITERS=300) LOGL 1 *