I am compiling a migration history database using SIPP data for about 220,000 respondents over 48 months. I have a monthly indicator (inter[i]) of whether a migration occured or not, and I have computed a variable (intermig[i]) that represents whether a migration has occurred in the past. I now need to compute a measure of the date of migration, and have that variables stay be constant by migration. Here's an example of what I want the data to look like (in long format).

t inter intermig cminter interview 0 0 0 0 616 1 0 0 0 617 2 1 1 618 618 3 0 1 618 619 4 0 1 618 620 5 0 1 618 621 6 0 1 618 622

My data is currently in wide format and so the code below effectively creates 'intermig,' but the second part where cminter is computed does not work, and I get zeros on all obs. Is SAS not able to process the cminter[j]=interview[i] command? Thanks for your help.

/*Interstate Migrants*/ do i=2 to 48; if inter[i] eq 1 then do; do j=i to 48; intermig[j]=1; end; leave; end; else intermig[i]=0;

if inter[i] eq 1 then do; do j=i to 48; cminter[j]=interview[i]; end; leave; end; else cminter[i]=0; end;