This text reviews a set of widely used summary inequality measures, and the lesser known relative distribution method provides the basic rationale behind each and discusses their interconnections. It also introduces model-based decomposition of inequality over time using quantile regression. This approach enables researchers to estimate two different contributions to changes in inequality between two time points.

Key Features:

- Clear statistical explanations provide fundamental statistical basis for understanding the new modeling framework

- Straightforward empirical examples reinforce statistical knowledge and ready-to-use procedures

- Multiple approaches to assessing inequality are introduced by starting with the basic distributional property and providing connections among approaches

This supplementary text is appropriate for any graduate-level, intermediate, or advanced statistics course across the social and behavioural sciences, as well as individual researchers.