/* A program to prepare data for a conditional logit 
and estimate it */

#delimit;
set mem 3000k;

log using clogit.log, replace;

use ps206hw7;

generate id = _n;          /* created a variable for ID# */

generate choice = 1;      /* to keep track of which canidate 
                             this sub-dataset is for */

generate votec=0;
replace votec=1 if vote==1;    /* =1 if vote for Bush */

generate discand = disbush;

keep id choice votec discand gender educ age income;

save vbush, replace;

/* We need to do this so we can use the "append" command later */

clear;

use ps206hw7;

generate id = _n;  

generate choice = 2;

generate votec=0;
replace votec=1 if vote==2;    /* =1 if vote for Clinton */

generate discand = disclin;

keep id choice votec discand gender educ age income;

save vclin, replace;

clear;

use ps206hw7;

generate id = _n;      

generate choice = 3;

generate votec=0;
replace votec=1 if vote==3;    /* =1 if vote for Perot */

generate discand = dispero;

keep id choice votec discand gender educ age income;

save vpero, replace;

clear;

use vbush;
append using vclin;
append using vpero;

/* this stacks all of our sub-datasets into 1 dataset */

sort id;

generate cbush = 0;
replace cbush = 1 if choice==1;

generate cclin = 0;
replace cclin = 1 if choice==2;

/* creating data matrix, normalized wrt Perot */

generate bgen = gender*cbush;
generate cgen = gender*cclin;

generate beduc = educ*cbush;
generate ceduc = educ*cclin;

generate bage = age*cbush;
generate cage = age*cclin;

generate binc = income*cbush;
generate cinc = income*cclin;

/* estimate conditional logit */

clogit votec discand cbush cclin bgen cgen beduc ceduc bage cage binc cinc, 
group(id);