Looking at the help pages in the ineq package, the Theil() function simply returns the value of the index. You can look at the source code of the relevant functions to see what they actually compute:
library('ineq') ineq # the main function Theil # for the Theil index Neither function is long - ineq() is a wrapper for the index of choice. The code for Theil is very straightforward. It appears that if you want to decompose the index, you'll have to roll your own function to do so. If you know how to compute it componentwise, you could write a function to get the necessary information in each group, and then use that information to compute the overall index. Here's a reproducible example using the chickwts data that computes means and sample sizes by feed type, then uses the result to compute a weighted mean: library('plyr') (v <- ddply(chickwts, .(feed), summarise, m = mean(weight), n = length(weight))) with(v, weighted.mean(m, n)) # [1] 261.3099 This is a template of how you might produce the components you need for the Theil index and them pull them together into a weighted sum or product, if that's what you need to do. HTH, Dennis On Tue, Nov 15, 2011 at 10:35 PM, Kitty Lee <lee.ki...@yahoo.com> wrote: > I came across the package 'ineq' that computes a variety of inequality > measures (e.g. gini, theil etc). I want to compute the Theil index (racial > segregation) and decompose the total into sub-components (by geog levels). I > think the package doesn't report the decomposition (correct me if I'm wrong). > Just wonder is that available elsewhere? > > > > K. > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.