I wanted to study inequalities in a health variable (negative of HAZ) and therefore wanted to generate concentration index with respect to wealth index score provided in the dataset.
The CI that i got by using conindex is -0.0275. While the CI generated by using the procedure laid down by Owen O' Donnell et. al. in their book was -0.129 which is same as reported by other researchers. Can someone tell me why is this difference coming and what it means in terms of interpretation. I have used the wealth index score for ranking the variables and have used svy wherever applicable.
I used the following command
*****For Conindex*****
conindex neghaz, rankvar(hv271) bounded limits (-6 6) svy
******2nd approach******
clear
set maxvar 10000
set more off
gen wt = hv005/1000000
svyset[pw=wt], psu(sh021) strata(hv022)
**** var Creation**
gen y= neghaz
quietly sum y [aw=wt]
sca m_y = r(mean)
display "mean of y", m_y
di m_y
**** GENERATE WEIGHTED FRACTIONAL RANK VARIABLE
gen x = hv271
sort x
egen raw_rank=rank(x), unique
sort raw_rank
quietly sum wt
gen wi=wt/r(sum)
gen cusum=sum(wi)
gen wj=cusum[_n-1]
replace wj=0 if wj==.
gen rank=wj+0.5*wi
qui sum y [aw=wt]
scalar mean=r(mean)
cor y rank [aw=wt], c
sca CI1=(2/mean)*r(cov_12)
display "concentration index by convenient covariance method", CI1
qui sum rank [aw=wt]
sca var_rank=r(Var)
gen lhs=2*var_rank*(y/mean)
regr lhs rank [pw=wt]
sca CI2=_b[rank]
display "concentration index by convenient regression method", CI2
Thanks in advance
The CI that i got by using conindex is -0.0275. While the CI generated by using the procedure laid down by Owen O' Donnell et. al. in their book was -0.129 which is same as reported by other researchers. Can someone tell me why is this difference coming and what it means in terms of interpretation. I have used the wealth index score for ranking the variables and have used svy wherever applicable.
I used the following command
*****For Conindex*****
conindex neghaz, rankvar(hv271) bounded limits (-6 6) svy
******2nd approach******
clear
set maxvar 10000
set more off
gen wt = hv005/1000000
svyset[pw=wt], psu(sh021) strata(hv022)
**** var Creation**
gen y= neghaz
quietly sum y [aw=wt]
sca m_y = r(mean)
display "mean of y", m_y
di m_y
**** GENERATE WEIGHTED FRACTIONAL RANK VARIABLE
gen x = hv271
sort x
egen raw_rank=rank(x), unique
sort raw_rank
quietly sum wt
gen wi=wt/r(sum)
gen cusum=sum(wi)
gen wj=cusum[_n-1]
replace wj=0 if wj==.
gen rank=wj+0.5*wi
qui sum y [aw=wt]
scalar mean=r(mean)
cor y rank [aw=wt], c
sca CI1=(2/mean)*r(cov_12)
display "concentration index by convenient covariance method", CI1
qui sum rank [aw=wt]
sca var_rank=r(Var)
gen lhs=2*var_rank*(y/mean)
regr lhs rank [pw=wt]
sca CI2=_b[rank]
display "concentration index by convenient regression method", CI2
Thanks in advance
