This paper addresses the lack of connection between theory and empirics in most export diversification - economic development studies. We provide a Ricardian-based theoretical explanation of countries' relative export variety as a function of the level of technology and country size assessed with respect to the rest of the world. Relative export diversification is an outcome of two forces: a relative productivity change (technological progress) and a relative country size change (labour force growth). The model predictions are confirmed in a sample of 132 countries (1988-2014), including 53 low-income countries, for which we measure export variety using product-level trade data. The influence of technology differences on export variety is: (i) stronger than is the effect of cross-country differences in size and (ii) non-linear, driving diversification at the beginning of the development process. The results are robust to the measurement of export variety, the inclusion of control variables, and estimation methods.
export variety export diversification Ricardian model economic development