Herfindahl: Herfindahl Index of Concentration
In SciencesPo: A Tool Set for Analyzing Political Behavior Data

Description Usage Arguments Details References See Also Examples

Calculates the Herfindahl Index of concentration.

Herfindahl(x, n = rep(1, length(x)), base = 1, na.rm = FALSE, ...)

## Default S3 method:
Herfindahl(x, n = rep(1, length(x)), base = NULL,
  na.rm = FALSE, ...)

`x`	a vector of data values of non-negative elements.
`n`	a vector of frequencies of the same length as `x`.
`base`	a parameter of the concentration measure (if `NULL`, the default parameter (1.0) is used instead).
`na.rm`	a logical. Should missing values be removed? The Default is set to `na.rm=FALSE`.
`...`	additional arguements (currently ignored)

This index is also known as the Simpson Index in ecology, the Herfindahl-Hirschman Index (HHI) in economics, and as the Effective Number of Parties (ENP) in political science.

Cowell, F. A. (2000) Measurement of Inequality in Atkinson, A. B. / Bourguignon, F. (Eds): Handbook of Income Distribution. Amsterdam.

Cowell, F. A. (1995) Measuring Inequality Harvester Wheatshef: Prentice Hall.

Atkinson, Rosenbluth, PoliticalDiversity, Gini. For more details see the Indices vignette: vignette("Indices", package = "SciencesPo")

# generate a vector (of incomes)
x <- c(778, 815, 857, 888, 925, 930, 965, 990, 1012)

# compute the Herfindahl coefficient with base=1
Herfindahl(x, base=1)