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The Dual Theory of Measuring Social Welfare and Inequality. Winter School (University of Verona) , Canazei, 12-16 January 2009. Rolf Aaberge Research Department, Statistics Norway. Outline. 1. MOTIVATION. 2. Expected and rank-dependent utility theories of social welfare.
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The Dual Theory of Measuring Social Welfare and Inequality Winter School (University of Verona), Canazei, 12-16 January 2009 Rolf Aaberge Research Department, Statistics Norway
Outline 1 MOTIVATION 2 Expected and rank-dependent utility theories of social welfare Statistical characterization of income distributions and Lorenz curves 3 Normative theories for ranking Lorenz curves 4 Ranking Lorenz curves and measuring inequality when Lorenz curves intersect 5
Problem Consider a set of income distributions How should we rank and summarize differences between these distributions? Introduce an ordering relation which justifies the statement
Rank-dependent utility based theory of social welfare where P(t) is an increasing concave function of t.
Rank-dependent measures of inequality Since and obeys the Pigou-Dalton transfer principle Yaari (1988) proposed the following family of rank-dependent measures of inequality
Statistical characterization of income distributions and Lorenz curves
Gini’s Nuclear Family Bonferroni: Gini: Aaberge, R. (2007): Gini’s Nuclear Family, Journal of Economic Inequality, 5, 305-322.
Normative theories for ranking Lorenz curves By defining the ordering relation on the set of Lorenz curves L rather than on the set of income distributions F, Aaberge (2001) demonstrated that a social planner who supports the Von Neumann – Morgenstern axioms will rank Lorenz curves according to the criterion
Alternatively, ranking Lorenz curves by relying on the dual independence axiom for Lorenz curves rather than on the conventional independence axiom is equivalent to employ the following measures of inequality where Q´(t) is a positive increasing function of t.
Ranking Lorenz curves and measuring inequality when Lorenz curves intersect How robust is an inequality ranking based on the Gini coefficient or a few meausures of inequality?
The principles of first-degree downside and upside positional transfer sensitivity