help egen_inequal
-------------------------------------------------------------------------------

Title

    [D] egen -- Extensions to generate inequality and poverty measures

Syntax for FGT poverty measures

        egen [type] newvar = fgt(varname) [if] [in] , pline(varname or #) [
              by(varlist) weights(varname) alpha(#) ]

Syntax for inequality measures

        egen [type] newvar = inequal(varname) [if] [in] [, by(varlist)
              weights(varname) index(fcn) ]

    Or alternatively,

        egen [type] newvar = fcn(varname) [if] [in] [, by(varlist) weights(
              varname)]

Description

    The set of programs in this package uses egen to create newvar of the
    optionally specified storage type equal to one of the standard inequality
    and Foster-Greer-Thorbecke (FGT) poverty measures.

    (Note that egen may change the sort order of your data).

Options

        +----------------+
    ----+ Common options +---------------------------------------------------

    The option by(varlist) means that computations are performed separately
    for each group defined by varlist.

    The option weights(varname) means that computation of poverty and
    inequality measures are performed with weights taken from the values of
    variable varname.

        +--------------------------+
    ----+ Poverty function options +-----------------------------------------

    pline(varname or #) is a non-optional parameter that defines the poverty
    line.  The poverty line could be specified either as a variable or as a
    numeric value.

    alpha(#) is an optional positive argument that specifies the parameter in
    the FGT-type poverty measures. alpha(0) corresponds to poverty rate;
    alpha(1) corresponds to average poverty gap index; alpha(2) corresponds
    to severity of poverty index. By default (alpha is not specified) the
    poverty rate is generated.

        +-----------------------------+
    ----+ Inequality function options +--------------------------------------

    An optional parameter index(fcn) specifies the inequality function fcn
    that generates a new variable. The Gini inequality index is the default
    option (index is not specified).  Alternative syntax uses the type of
    inequality index directly to generate the new variable.  No index(fcn)
    parameter needs to be specified in that case. See examples for
    explanation.

    list of inequality functions fcn:

    -------------------------------------------------------------------------
      rmd        the relative mean deviation
      cov        the coefficient of variation
      sdl        the standard deviation of logs
      gini       the Gini index
      mehran     the Mehran index
      piesch     the Piesch index
      kakwani    the Kakwani index
      theil      Theil entropy index
      mld        the mean log deviation
      entropy    generalized entropy measure (GE -1)
      half       generalized entropy measure (GE 2)
    -------------------------------------------------------------------------

Examples

    To create a new variable gini_reg containing the value of gini
    coefficient for the distribution of household expenditure expend by
    region using household weight hhweight:

        . egen gini_reg = inequal(expend), by(region) weight(hhweight)
        index(gini)

      Alternative syntax:

        . egen gini_reg = gini(expend), by(region) weight(hhweight)

    To create a new variable mld_ur containing the value of mean log
    deviation for the distribution of household expenditure expend by urbrur
    (urban and rural) using household weight hhweight:

        . egen mld_ur = inequal(expend), by(urbrur) weight(hhweight) ind(mld)

      Alternative syntax:

        . egen mld_ur = mld(expend), by(urbrur) w(hhweight)

    To create a new variable p1_reg containing value of the average poverty
    gap corresponding to the poverty line specified in variable rpl for the
    distribution of household expenditure expend by region using household
    weight hhweight:

        . egen p1_reg = fgt(expend), by(region) weight(hhweight) pl(rpl)
        alpha(1)

    To create a new variable p0_reg containing the poverty rate corresponding
    to the poverty line equal to 1234 for the distribution of household
    expenditure expend by region using household weight hhweight:

        . egen p0_reg = fgt(expend), by(region) w(hhweight) pl(1234) a(0)

Authors

    M. Lokshin and Z. Sajaia (DECRG, The World Bank).

Also see

    Online:  help for egen, if installed: rspread, inequal, ineqdeco, 
             poverty, povdeco