st: Yitzhaki index

["Frank Elgar, Dr." <frank.elgar@mcgill.ca>]

Dear Statalist,

My dataset contains a group variable (schoolID) and affluence variable
(FAS).  I want to calculate Yitzhaki's (1979) index of relative
deprivation for each individual within schools, the reference group. The
Yitzhaki index is simply the average distance that separates the income of
each individual from all higher incomes in the group.  As such, feelings
of deprivation are based on upward comparisons.

It does not seem that complicated but I cannot sort out the syntax.

I have been tried things along the lines of

by schoolID, sort: egen totFAS=total(FAS)
by schoolID, sort: egen maxFAS=max(FAS)
by schoolID, sort: egen schoolsize=count(FAS)
by schoolID, sort: generate
yitz=(((total(FAS))-FAS)/schoolsize-1)-FAS)/(size-1)
by schoolID, sort: replace yitz=0 if FAS>=maxFAS

But this isn't even close. The distances must be based on all higher FAS
values within each schoolID. Any suggestions?


Frank J Elgar, PhD
McGill University


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