Compute the progressivity

progressivity(income, tax, measure = c("Reynolds-Smolensky", "Kakwani"))

Arguments

income	Pre-tax income.
tax	Tax paid.
measure	Currently, only "Reynolds-Smolensky" progressivity is calculated: $$G_Y - G_Z$$ where $G_Y$ is the Gini coefficient of `income` and $G_X$ is the Gini coefficient of post-tax income.

The progressivity measure. Positive for progressive tax systems, and higher the value the more progressive the system.


I <- c(10e3, 20e3, 50e3, 100e3, 150e3)
progressivity(I, 0.3 * I) # zero
#> [1] 0
progressivity(I, income_tax(I, "2017-18"))
#> [1] 0.04856361