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{* March 2015}{...}
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help for {hi:dicseg (Version 2.2)}{right:Carlos Gradín (March 2015)}
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{title:Segregation indices with optional segregation curve for the case of two groups with either individual data or aggregated data}
(For multigroup cases see {help localseg})
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-For individual data (each observation is an individual):
{p 8 17 2} {cmd:dicseg} {it:unitvar} {it:groupvar} [{it:weights}] [{cmd:if} {it:exp}] [{cmd:in} {it:range}]
[, {cmdab:nor:malize} {cmdab:f:ormat}{it:(%9.#f)} {cmdab:sc:} {cmdab:no:graph} {cmdab:x:}{it:(newvar)} {cmdab:y:}{it:(newvar)} {cmdab:xt:itle}{it:(xtitle)} {cmdab:yt:itle}{it:(ytitle)} {cmdab:gr:aph_options}{it:(graph_options)} ]
{p 4 4 2} {cmd:fweights}, {cmd:aweights} and {cmd:aweights} are allowed; see {help weights}.
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-For aggregated data (each observation is a unit):
{p 8 17 2} {cmd:dicseg} {it:unitvar} {it:group1var} {it:group2var} [{cmd:if} {it:exp}] [{cmd:in} {it:range}]
, {cmdab:ag:gregate} [ {cmdab:nor:malize} {cmdab:f:ormat}{it:(%9.#f)} {cmdab:sc:} {cmdab:no:graph} {cmdab:x:}{it:(newvar)} {cmdab:y:}{it:(newvar)} {cmdab:xt:itle}{it:(xtitle)} {cmdab:yt:itle}{it:(ytitle)} {cmdab:gr:aph_options}{it:(graph_options)} ]
{title:Important}
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It requires to have {cmd: matsort}, written by Paul Millar, previously installed; if not, install it writing in the command line:
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. net install matsort, all from(http://fmwww.bc.edu/RePEc/bocode/m)
{title:Description}
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{cmd:dicseg} computes segregation indices across units in a two-group context.
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By default, microdata (individual observations) are required.
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{it:unitvar} indicates units (ex. occupations, census tracts, schools, ....).
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{it:groupvar} is a dichotomous variable identifying two groups such as gender (male vs. female), race (white versus non-white), ...
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For data aggregated by unit (each observation is a unit), use the {cmdab:ag:gregate} option .
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{it:unitvar} indicates units (ex. occupations, census tracts, schools, ....).
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{it:group1var} and {it:group2var} identify the variables that give the number (or proportion) of individuals from the first and second group respectively in each unit.
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If option {cmdab:sc:} is specified it also draws the segregation curve, and creates new variables using {cmdab:x:}{it:(newvar)} and {cmdab:y:}{it:(newvar)} options.
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{cmd:x} represents the group with the lowest value in {it:groupvar} and {cmd:y} the group with the highest value.
{title:Reporting}
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Segregation indices (for formulae and details, see {browse "http://webs.uvigo.es/cgradin/Measuring_Segregation_Using_Stata__The_Two_group_Case.pdf": Gradín, 2014}):
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. Dissimilarity index.
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. KM, the Karmel and Maclachlan (1988) index.
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. GE(alpha) with alpha= -2, -1, 0, .10, .25, .50, .75, .90, 1, 2 is the family of Generalized Entropy measures for different values of the segregation sensitivity parameter. GE(1) is also known as Theil index.
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Note: GE is infinite for some alpha when one group has no observations at one or more units: GE(alpha>=1) if group 1; GE(alpha<=0) if group 2. In those cases only finite cases are reported.
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. Squared Root (Hutchens, 1991, 2004) is equivalent to GE(.5)/4
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. A(epsilon) with epsilon= .10, .25, .50, .75, .90, 1, 2, 4 is the family of Atkinson indices for different values of the segregation sensitivity parameter.
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Note: A(epsilon>1) is infinite when group 2 has no observations at one or more units. In those cases only finite cases are reported.
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. Mutual Information (e.g. Theil and Finizza, 1971) using log(2).
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. Gini, the Gini index.
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All indices take the value 0 when there is no segregation because both groups have the same distribution across units.
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Dissimilarity, Squared Root, A, M, Gini take the value 1 when segregation is at its maximum (no overlapping distributions).
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Segregation Curve (if option {cmdab:sc:} is specified): as defined in Duncan and Duncan (1955) or Hutchens (1991).
{title:Options}
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{cmdab:ag:gregate} to use aggregated data, the default is to use individual data.
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{cmdab:nor:malize} to normalize GE(0{break}
Facultade de CC. Económicas{break}
Universidade de Vigo{break}
36310 Vigo, Galicia, Spain.
{title:References}
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Duncan, Otis D. and Duncan, Bervely (1955), A Methodological Analysis of Segregation Indexes, American Sociological Review, 20(2): 210-217.
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Gradín, Carlos (2014), {browse "http://webs.uvigo.es/cgradin/Measuring_Segregation_Using_Stata__The_Two_group_Case.pdf": Measuring Segregation using Stata}, Universidade de Vigo.
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Hutchens, Robert M. (1991), Segregation Curves, Lorenz Curves, and Inequality in the Distribution of People across Occupations, Mathematical Social Sciences, 21: 31- 51.
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Hutchens, Robert M. (2004), One Measure of Segregation, International Economic Review 45(2): 555-578.
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Karmel, T. and Maclachlan M. (1988), Occupational Sex Segregation - Increasing or Decreasing, Economic Record, 64: 187-195.
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Theil, Henri and Anthony J. Finizza (1971), A Note on the Measurement of Racial Integration of Schools by Means of Informational Concepts, Journal of Mathematical Sociology, 1: 187-194
{title:Also see}
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{help duncan} if installed; {help hutchens} if installed; {help localseg} if installed; {help seg} if installed