The impact of ECLAC's work can be measured through the global influence of its economic theories on Latin American development. Many of the theories have challenged existing economic approaches and have given new tools to Latin American policy-makers. .
In the immediate aftermath of World War II, ECLAC, then under the leadership of economist Raul Prebisch, published an analysis of the economic development of Latin America. The analysis attempted to explain the causes of underdevelopment within the framework of a comparative analysis between industrialized and developing nations. Prebisch introduced the structuralist economic theory, which focused on the understanding of the world economy in terms of a "center-periphery- structure. Industrialized nations formed the center and developing states the periphery. The theory proposed that underdevelopment was the direct consequence of unequal trading relations. Specifically, industrialized nations were selling increasingly expensive manufactured goods to the periphery in return for raw materials at increasingly unfavorable terms of trade for underdeveloped countries. The disadvantageous terms of trade for the periphery created a form of imperialism and, to some extent, a dependence on industrialized markets. According to Prebisch, the only way out of dependency was through industrialization and sustained growth of the peripheral economies. .
The theory of structural economic dependency gained increasing favor as the basis for Latin American economic policies. Economic exploitation and political manipulation by rich countries presented a good explanation for the underdeveloped condition of many Latin American countries. The assumption was that Latin America was not responsible for its underdevelopment since industrialized nations controlled world trade relations. .
While dependency theory highlights some truths - e.g., the consequences, particularly for small countries, of world price fluctuations for un-diversified economies, the export of recession from the rich countries to the poor countries - it implies that Latin America is impotent and that the course of its history determined by outside forces.