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st: concentration indices and SEs (Was: Postlist for bootstrap)

From   <>
To   <>
Subject   st: concentration indices and SEs (Was: Postlist for bootstrap)
Date   Tue, 4 Jun 2013 10:12:19 +0100


Date: Mon, 3 Jun 2013 17:26:14 +0200
From: Vincenzo Carrieri <>
Subject: st: Postlist for bootstrap

Dear Statalisters,
I am trying to implement bootstrap estimations of standard errors for
concentration indexes but I get an error like: the variable "sesso"
(name of the first variable that I use in the regression) was not
found. I think that the problem is mostly on the use of postfile but I
cannot find the solution.

Here an example of what I did using just few variables.

I first using data:

use "C:\Users\User\Desktop\TEST.dta", replace

Then I Declare variable names and filename of dataset where results
will be stored

postfile test2 my ciy m01 b01 ci01 using

Then I launch my programme

capture program drop index
program define index
regress sesso eta
predict sesso
sum sesso
scalar my = r(mean)
sum eta
scalar m01=r(mean)

tempname my ciy m01 b01  ci01
sca b01 = _b[eta]
gen rank=reddito

I compute  concentration indices
  corr rank sesso        , c
     sca ciy           = 2*r(cov_12)/my
  corr rank eta        , c
     sca ci01           = 2*r(cov_12)/m01

post stak my ciy m01 b01 ci01


Up to now everything is ok.

Finally I do boostrap:

bootstrap , reps(10) : index

Here I get the error message: variable sesso not found an error
occurred when bootstrap executed index

My code  would continue:

I close the postfile

postclose test2

use "C:\Users\User\Desktop\test.dta", replace

sum my ciy m01 b01 ci01

Anyone can help me to understand what is wrong in my bootstrap

Any help is appreciated.


Not the answer to your question, but ...

... For calculation of concentration indices and bootstrapping, I
recommend the -sgini- package by Philippe Van Kerm.

Look at , which has the program
(downloadable) plus good documentation

Install the package from within Stata by typing:
    net describe sgini , from( 


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