KolmPollak: Kolm-Pollak Inequality Index adjustable for indexing...

In ejanalysis/ejanalysis: Tools for Environmental Justice (EJ) Analysis

Kolm-Pollak Inequality Index adjustable for indexing inequality in bad outcomes

Description

This is a simple wrapper for the ineq::Kolm function, but it makes explicit the need to transform x first if x measures a harm or cost.

Usage

KolmPollak(x, parameter = 1, na.rm = TRUE, bigbadx = FALSE)

Arguments

x	Same as in ineq::Kolm().
parameter	Same as in ineq::Kolm().
na.rm	Same as in ineq::Kolm().
bigbadx	Optional, default is FALSE. Setting bigbadx = TRUE means bigger x values are bad, as in the case of x measuring levels of risk to health, or exposure to a pollutant. If bigbadx=TRUE, the x values are first transformed into 0 - x

Details

The Kolm-Pollak inequality index is provided by the package ineq but that index is only suitable for use with a variable where larger values are preferred, such as with income. The need for this type of transformation is noted by Maguire and Sheriff (2011) in http://dx.doi.org/10.3390/ijerph8051707 Many variables represent negative outcomes, such as measures of risks to health, or costs. For those types of variables, the variable should first be transformed by multiplying it by negative one. This function does that when a parameter is set appropriately.

The typical KP index says inequality is worse if some incomes are very low (than if some are very high). The adjusted KP index says inequality is worse if some costs or health risks are very high (than if some are very low).

Value

This returns what Kolm does, except if bigbadx=TRUE it first transforms x.

Examples

 # Typical KP index says
 #   inequality is worse
 #   if some incomes are very low
 #   (than if some are very high):
 KolmPollak(c(-5,0,1), bigbadx = FALSE) #[1] 2.577229
 KolmPollak(c(-1,0,5), bigbadx = FALSE) #[1] 1.549793

 # Adjusted KP index says
 #   inequality is worse
 #   if some costs or health risks are very high
 #   (than if some are very low):
 KolmPollak(c(-1,0,5), bigbadx = TRUE) #[1] 2.577229
 KolmPollak(c(-5,0,1), bigbadx = TRUE) #[1] 1.549793

 set.seed(99)
 x=rep(c(1,2,5),50)*rnorm(mean=1, sd=0.2, n=50*3)
 ineq::Kolm(x)
 KolmPollak(x)
 KolmPollak(x, bigbadx = TRUE)

ejanalysis/ejanalysis documentation built on April 2, 2024, 10:12 a.m.