st: different result everytime - something strange

[Shehzad Ali <sia500@york.ac.uk>]

Hi listers,

I have encountered a funny problem, which maybe due to something wrong with 
my codes or with stata. I am trying to calculate concentration index using 
convenient regression method but everytime I run my do file, I get 
different results using exactly the same data. I am sure someone can help.

Here is what I am doing:

glcurve y [aw=weight], pvar(rank) replace nograph      
qui sum x [fw=weight]	
scalar mean=r(mean)      
qui sum rank [fw=weight]   
sca var_rank=r(Var)     
gen lhs=2*var_rank*(x/mean)          
regr lhs rank [pw=weight], cluster(commune)      
sca CI=_b[rank]        
display "concentration index", CI

Any help would be appreciated.

Shehzad

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