{smcl} {* April 2014}{...} {hline} help for {hi:rq (Version 1)}{right:Carlos Gradín (April 2014)} {hline} {title:Ethnic Polarization index, Reynal-Querol (J. of Conflict Resolution, 2002)} {title:Syntax} {p 8 17 2} {cmd:rq} {it:varname} [{it:weights}] [{cmd:if} {it:exp}] [{cmd:in} {it:range}] {p 12 4 2} {it:varname} indicates the variable of interest (ex. ethnic group, religion, ...). {p 12 4 2} {cmd:fweights}, {cmd:aweights} and {cmd:aweights} are allowed; see {help weights}. {title:Description} {p 4 4 2} {cmd:rq} computes the ethnic polarization index proposed by Reynal-Querol (2002), related to Esteban and Ray (Econometrica, 1994) polarization measure, using either individual data or data aggregated by groups. {title:Formula} RQ = 1 - sum_i [(.5-pi)^2*pi / .25 ] = 4*sum_i [pi^2*(1-pi)] {p 8 4 2} where pi is the proportion of members of the ith group. RQ is between 0 and 1. {title:Saved results} {p 4 4 2} Scalar: {p 8 8 2} r(rq) {title:Examples} {p 4 4 2} Example of data: individual ethnicity weight 1 2 2 2 2 3 3 1 3 1 3 1 {p 4 8 2} . {stata rq ethnicity [aw=weight]} {p 4 4 2} Example of data: aggregated by groups ethnicity weight 1 .2 2 .5 3 .3 {p 4 8 2} . {stata rq ethnicity [aw=weight]} In both cases the result is the same: . Reynal-Querol index (J of Conflict Resolution, 2002) = 0.8800 {p 4 8 2} For bootstrapping (BC estimates), using saved scalars {p 8 8 2} cap program drop reyq {p 8 8 2} program def reyq {p 12 8 2} rq ethnicity [aw=weight] {p 8 8 2} end {p 8 8 2} bootstrap r(rq) , reps(1000): reyq {p 8 8 2} estat bootstrap {title:Author} {p 4 4 2}{browse "http://webs.uvigo.es/cgradin": Carlos Gradín} {break} Facultade de CC. Económicas{break} Universidade de Vigo{break} 36310 Vigo, Galicia, Spain. {title:References} {p 4 8 2} Esteban, Joan Maria and Debraj Ray (1994), On the Measurement of Polarization, Econometrica, 62(4):819-851. Montalvo, José G. and Marta Reynal-Querol (2005), "Ethnic Polarization, Potential Conflict, and Civil Wars", American Economic Review, 95(3): 796-816. Reynal-Querol, Marta (2002), Ethnicity, Political Systems, and Civil Wars, Journal of Conflict Resolution, 46(1): 29-54. {title:Also see} {p 4 13 2} {help er} if installed.