آیا نابرابری درآمد صرفه جویی کل را افزایش می دهد ؟

This paper reviews analytically and empirically the links between income distribution and aggregate saving. Consumption theory brings out a number of direct channels through which income inequality can affect overall household saving — positively in most cases. However, recent political-economy theory points toward indirect, negative effects of inequality — through firm investment and public saving — on aggregate saving. On theoretical grounds, the sign of the saving–inequality link is therefore ambiguous. This paper presents new empirical evidence on the relationship between income distribution and aggregate saving based on a new and improved income distribution database for both industrial and developing countries. The empirical results, using alternative inequality and saving measures and various econometric specifications on both cross-section and panel data, provide no support for the notion that income inequality has any systematic effect on aggregate saving. These findings are consistent with the theoretical ambiguity.

The theoretical relation between saving and income distribution has received attention both in the historical growth literature and more recent neoclassical consumption theory. In fact, the link between the functional distribution of income and saving (and growth) is at the heart of the neoclassical growth model (Solow, 1956) as well as neo-Keynesian growth models Lewis, 1954, Kaldor, 1957 and Pasinetti, 1962. In more recent neoclassical consumption theory, the focus is on the links between personal distribution of income and aggregate saving as a result of consumer heterogeneity in regard to endowments or institutional constraints (see Deaton, 1992 for a discussion). Most (but not all) of the mechanisms pointed out by the above mentioned theories suggest positive direct effects of income inequality on overall personal saving. However, recent political-economy research brings out negative indirect links from inequality — through investment, growth, or public saving — to aggregate saving (e.g., Dornbusch and Edwards, 1991, Persson and Tabellini, 1994 and Alesina and Perotti, 1996). Taken together, these two strands of the literature imply that the overall impact of inequality on aggregate saving is theoretically ambiguous and can only be assessed empirically. Most of the empirical literature on the links between personal income inequality and personal saving based on cross-section micro data suggest a positive relation between them (e.g., Bunting, 1991 and Dynan et al., 1996). In turn, the evidence from aggregate (typically cross-country) data is more mixed. Some studies also find positive and significant effects of personal income inequality on aggregate saving Sahota, 1993, Cook, 1995 and Hong, 1995, but other studies do not Della Valle and Oguchi, 1976, Musgrove, 1980 and Edwards, 1996. Reconciling these conflicting results is difficult because empirical studies based on macro data use different samples and specifications, different measures of saving and inequality and, in most cases, income distribution information of questionable quality. This paper reexamines the empirical evidence from macro data on the links between the distribution of personal income and aggregate saving, controlling for relevant saving determinants. It provides an encompassing framework and a robustness check for previous empirical studies, and extends them in five dimensions: (i) testing alternative saving specifications; (ii) using alternative inequality and saving measures; (iii) making use of newer, better and larger databases; (iv) conducting estimations jointly and separately for industrialized and developing countries; and (v) applying various estimation techniques on both cross-country and panel data. On the whole, we do not find any consistent effect of income inequality on aggregate saving — a result that is consistent with the theoretical ambiguity.2 The paper is organized as follows. Section 2 provides a brief literature survey on the links between income distribution and saving determination. Section 3 reviews previous empirical studies of the impact of income distribution on saving. A description of the large database on inequality and saving, used in this paper, follows. Section 5 presents new econometric evidence and Section 6 concludes.

The historical growth literature and more recent neoclassical consumption theory point out various channels through which income inequality affects personal saving. Most of these mechanisms (but not all) suggest positive direct effects of income inequality on overall personal saving. However, recent political-economy research brings out negative indirect links from inequality (through investment, growth, and public saving) to aggregate saving. Taken together, these two strands of the theoretical literature imply that the overall impact of inequality on aggregate saving is ambiguous and can be assessed only empirically. The empirical literature based on household data typically finds a positive relation between personal income inequality and overall personal saving. In turn, some empirical studies based on macro (national accounts) saving data, typically conducted on cross-country samples, also report positive effects of personal income inequality on aggregate saving. Other studies, however, find the opposite result or no effect whatsoever. Reconciling these conflicting results is difficult because macro-based empirical studies use widely different samples and specifications, different measures of saving and inequality and in most cases income distribution information of questionable quality. This paper has reexamined the empirical evidence from macro data on the links between the distribution of personal income and aggregate saving, controlling for relevant saving determinants, providing an encompassing framework and a robustness check for previous empirical studies, and extending them in five dimensions: (i) testing alternative saving specifications; (ii) using alternative inequality and saving measures; (iii) making use of newer, better, and larger databases; (iv) conducting estimations jointly and separately for industrialized and developing countries; and (v) applying various estimation techniques on both cross-country and panel data. On the whole, we do not find any consistent effect of income inequality on aggregate saving — a result that agrees with the theoretical ambiguity.