The inequality dataset compiled in the 1990s by the World Bank and extended by the United Nations has been both widely used and strongly criticized. The criticisms raise questions about conclusions drawn from secondary inequality datasets in general. The authors develop techniques to deal with...

Index of refraction is found to be a good measure of economic inequality within the Lorenz curve framework. It has origin in geometrical optics, where it measures bending of a ray of light passing from one transparent medium into another. As light refracts according to characteristics of...