Productivity and the Middle Class: Saving Market Validation and the Durability of Growth

This working paper develops a two-condition explanation of sustained economic growth. Domestic saving finances capital accumulation, while productivity determines whether that capital continues to generate value after protection, exceptional commodity prices, unused capacity, or extraordinary state demand recede. The paper argues that productivity also depends on access to a broad and technologically demanding middle class. Countries may obtain this demand domestically or through exports of their own value added to advanced consumer markets. The empirical analysis combines a modern country-cohort panel with historical case studies beginning in 1960. The panel uses OECD Trade in Value Added, World Bank, and Penn World Table data and examines manufacturing value added, total factor productivity, and output per unit of capital. The historical analysis covers South Korea, China, Brazil, Mexico, East Germany, the Soviet Union and Russia, and very poor economies represented by Madagascar, Niger, and Burundi. South Korea provides the principal positive case: high saving, coordinated capability formation, and export discipline transformed access to foreign middle-class demand into domestic technological development. China confirms this mechanism while revealing the later risks of overaccumulation. Brazil and Mexico illustrate different incomplete combinations of saving and market access. The remaining cases identify protected, resource-dependent, state-directed, and low-saving growth regimes. The paper defines spurious growth as the portion of measured expansion that cannot reproduce comparable civilian prosperity once its exceptional supporting condition disappears.