Prebisch–Singer hypothesis

In economics, the Prebisch–Singer hypothesis (also called the Prebisch–Singer thesis) argues that the price of primary commodities declines relative to the price of manufactured goods over the long term, which causes the terms of trade of primary-product-based economies to deteriorate. As of 2013^[update], recent statistical studies have given moderate support for the idea. The idea was initially developed by Hans Singer in 1948–49 and expanded by Raúl Prebisch shortly thereafter; since that time, it has served as a major pillar of dependency theory and policies such as import substitution industrialization (ISI).

A common explanation for this supposed phenomenon is that manufactured goods have a greater income elasticity of demand than primary products, especially food. Therefore, as incomes rise, the demand for manufactured goods increases more rapidly than demand for primary products. In addition, primary products have a low price elasticity of demand, so a decline in their prices tends to reduce revenue rather than increase it.

This theory implies that the very structure of the global market is responsible for the persistent inequality within the world system. This provides an interesting twist on Wallerstein's neo-Marxist interpretation of the international order which faults differences in power relations between 'core' and 'periphery' states as the chief cause for economic and political inequality (However, the Singer–Prebisch thesis also works with different bargaining positions of labour in developed and developing countries). As a result, the hypothesis enjoyed a high degree of popularity in the 1960s and 1970s with neo-Marxist developmental economists and even provided a justification for an expansion of the role of the commodity futures exchange as a tool for development.

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