This paper introduces some relevant policy-oriented approaches that measure the economic impact of development on social inequality. Gini inequality is often used because of its flexible nature and both grouped and individual data are considered to reflect a clear influence on the changes in Gini inequality. First, the estimation of the Lorenz curve, a concept that is closely associated with Gini inequality, is illustrated. Next, using individual data, I deduce the factors influencing the increase or decrease in the inequality. I present an empirical illustration derived from a Vietnamese survey data of 5938 households' consumption expenditure, a part of Vietnam Living Standards Survey 1997-1998.