{smcl} {hline} help for {cmd:concindexi} {right:(Amadou Bassirou DIALLO: AFTPM, The World Bank and CERDI, Univ. of Auvergne)} {hline} {title:Estimation of the Concentration Index based on Kakwani and Wagstaff covariance formulae.} {p 4 4 2}{cmd:concindexi} [{it:varlist}] [{it:if}] [{it:in}] [{it:weight}] [ {cmd:,} {cmdab:w:elfarevar}{cmd:(}{it:varname}{cmd:)} {cmdab:f:ormat}{cmd:(}{it:format}{cmd:)} {cmdab:cu:rve} {cmdab:co:nvenient} {cmdab:cl:ean} } {p 4 4 2}where : {p 4 4 2}{it:welfarevar} is the welfare variable - not optional - , {p 4 4 2}{it:format} is the format type used to display results, {p 4 4 2}{it: clean} is to erase matrices and scalars created by the program, {p 4 4 2}{it: curve} is to graph lorenz curve for each indicator, {p 4 4 2}{it: convenient} is to use in addition the convenient regression method to compute the concentration index. {title:Description} {p 4 4 2}{cmd:concindexi} computes the concentration index on individual (micro) data. See work by Wagstaff and Kakwani. {title:Formulas} {p 4 4 2}The concentration index is computed as: C = 2 cov(yi,Ri) / µ {p 4 4 2}yi is the individual i's indicator variable (e.g. health status), {p 4 4 2}µ its mean {p 4 4 2}Ri his fractional rank in the socioeconomic distribution {p 4 4 2}Standard errors of C are obtained by a "covariance" or "formula" method: 1 1 2 2 Var(C) = - [ - sum (a ) - (1 + C) ] n n {p 4 4 2}where : yi a = - ( 2 Ri - 1 - C) + 2 - qi-1 - qi µ {p 4 4 2}and : 1 qi = - sum(yi) µn {p 4 4 2}is the ordinate of the concentration curve L(p), and q0 = 0. {title:Examples} {p 4 4 2}{cmd:. concindexi has_water has_elec, welf(quint) }{p_end} {p 4 4 2}{cmd:. concindexi has_water has_elec, welf(quint) cu cl)}{p_end} {p 4 4 2}{cmd:. concindexi has_water [aw=weight], we(quint) co by(urbrur)}{p_end} {p 4 4 2}{cmd:. concindexi var1 var2 [aw=weight], we(quint) f(%9.2f)}{p_end} {title:Saved Results} {p 4 4 2}Concentration indices are saved in matrice r(CII). {title:Author} {p 4 4 2} Amadou Bassirou DIALLO, AFTPM, The World Bank -and- CERDI, Univ. of Auvergne (France). {p 4 4 2}Email: {browse "mailto:adiallo5@worldbank.org":adiallo5@worldbank.org}, {browse "mailto:adiallo5@gmail.com":adiallo5@gmail.com} {title:Note} {p 4 4 2} This program has been initially developped to use the Demographic and Health Surveys (DHS). {title:Also see} {p 4 4 2}Online: help for {help concindexg}, {help ineqdeco}, {help inequal}, {help povdeco}, {help ineqerr} if installed. {p_end} {hline}