ABSTRACT
An essential preliminary to any inequality study is clarification of the nature of the distribution to be analyzed to ensure that it represents the appropriate concept of economic power and does so for each constituent unit. This chapter discusses the information provided by several alternative graphical summaries of distributions such as histograms, Pen's Parade, and Lorenz curves, plus the properties of some related and commonly-used measures of a distribution's dispersion, including the Gini coefficient. It focuses on two important classes of cardinal measures. The first is the Atkinson family derived from sets of assumptions about society's Social Welfare Function. The Generalized Entropy family of indices considered second has a rather different pedigree but is shown to be closely related to the Atkinson one and to have an additional property very useful for empirical work, namely, additive decomposability by population subgroup.
