بهره وری، تجارت و اثر بازار خانگی

This paper analyzes the international transmission and welfare implications of productivity gains and changes in market size when macroeconomic adjustment occurs both along the intensive margin of trade (changes in the relative price of existing varieties of tradable goods) and the extensive margin (creation and destruction of varieties). We draw a distinction between productivity gains that enhance manufacturing efficiency and gains that lower the cost of firms' entry and of product differentiation. Countries with lower manufacturing costs have higher GDP but supply their products at lower international prices. Instead, countries with lower entry costs supply a larger array of goods at improved terms of trade. Output growth driven by demographic expansions, as well as government spending, is associated with an improvement in international relative prices and firms' entry. While trade liberalization may result in a smaller array of goods available to consumers, efficiency gains from deeper economic integration benefit consumers via lower goods prices. The international transmission mechanism and the welfare spillovers vary under different asset market structures, depending on trade costs, the elasticity of labor supply, and consumers' taste for varieties.

A common view in trade and growth theory is that an increased supply of domestic goods is associated with the deterioration of a country's terms of trade, as the additional domestic supply is absorbed by international markets at falling prices. By the same token, stronger internal demand for domestic output reduces a country's supply of exports and improves its international prices. A key welfare implication is that domestic productivity gains are transmitted positively to the country's trading partners worldwide, thanks to changes in relative prices.1 If the set of goods that a country produces and exports change over time, however, the tenet that a growing economy must experience weaker terms of trade is questionable. As argued by Krugman (1989), when domestic producers take advantage of enhanced productivity to change the attributes of their products, that country may enjoy the benefits of technological progress without experiencing any fall in its international prices.

Understanding the determinants of international relative prices and their links with output and consumption growth is a key challenge to international macroeconomics and policy making. National wealth depends not only on the quantity of goods and services that a country can produce now and in the future, but also on the relative prices such goods and services can command in the international markets. Productivity innovations that raise a country's output may raise national welfare abroad to the extent that they drive down import prices. However, when innovations also change the attributes of consumption goods, leading to product diversification, a correct assessment of the value of output, consumption and imports to consumers requires an assessment of consumers' preferences for goods variety. In this paper we have provided a stylized framework to address these issues.