% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/distributional.R
\name{gb_dist_weight}
\alias{gb_dist_weight}
\title{Distributional weight for a recipient income}
\usage{
gb_dist_weight(income, eta = 1.3, reference = "median", income_data = NULL)
}
\arguments{
\item{income}{Numeric vector of recipient incomes (positive).
Equivalised household disposable income is the conventional
measure.}

\item{eta}{Numeric scalar. Income elasticity of marginal utility
of income. Default \code{1.3}.}

\item{reference}{Either \code{"median"} (default; use median of
\code{income} or \code{income_data} if supplied) or a numeric scalar
(use that income as reference).}

\item{income_data}{Optional numeric vector. Reference income
distribution for computing the median. Use, e.g., the ONS
household disposable income distribution. If \code{NULL} (default),
the median of \code{income} is used.}
}
\value{
A numeric vector of weights, same length as \code{income}.
}
\description{
Returns the Green Book distributional weight applied to net
benefits accruing to a recipient at income \code{income}, relative to
a reference income (median by default), under iso-elastic utility:
}
\details{
\deqn{w_i = (y_{ref} / y_i) ^ \eta}

Default \code{eta = 1.3} per HM Treasury Green Book Annex A3. Higher
eta places greater weight on lower-income recipients; sensitivity
tests at \code{eta = 0.8} and \code{eta = 2.0} are conventional.
}
\examples{
# Weights across deciles of a stylised income distribution
income_deciles <- seq(10000, 100000, length.out = 10)
gb_dist_weight(income_deciles)
}
\references{
HM Treasury (2022). The Green Book, Annex A3 on distributional
analysis.

Acland, D. and Greenberg, D.H. (2024). The Elasticity of Marginal
Utility of Income for Distributional Weighting and Social
Discounting: A Meta-Analysis. Journal of Benefit-Cost Analysis.
}
\seealso{
\code{\link[=gb_dist_weighted_npv]{gb_dist_weighted_npv()}}.

Other distributional: 
\code{\link{gb_dist_weighted_npv}()}
}
\concept{distributional}
