Engel's Law in the Global Economy: Demand‐Induced Patterns of Structural Change, Innovation, and Trade

Endogenous demand composition across sectors due to income elasticity differences, or Engel's Law for brevity, affects (i) sectoral compositions in employment and in value‐added, (ii) variations in innovation rates and in productivity change across sectors, (iii) intersectoral patterns of trade across countries, and (iv) product cycles from rich to poor countries. Using a two‐country model of directed technical change with a continuum of sectors under nonhomothetic preferences, which is rich enough to capture all these effects as well as their interactions, this paper offers a unifying perspective on how economic growth and globalization affect the patterns of structural change, innovation, and trade across countries and across sectors in the presence of Engel's Law. Among the main messages is that globalization amplifies, instead of reducing, the power of endogenous domestic demand composition differences as a driver of structural change.

The Missing Food Problem: Trade, Agriculture, and International Productivity Differences

Agriculture in poor countries has low productivity, high employment, and negligible trade flows relative to other sectors. These facts motivate a multisector, open-economy view of international productivity differences. With a quantitative multicountry model featuring nonhomothetic preferences, multiple interrelated sectors, distorted labor markets, and costly trade, I find: trade amplifies the negative effect of labor market distortions; trade costs—large for poor countries, especially in agriculture—significantly contribute to international productivity differences; and explicitly modeling agriculture reveals additional channels through which poor countries may gain from trade. (JEL F41, J24, J43, O13, O19, Q11, Q17)

Exclusive Goods and Formal-Sector Employment

We explore how the underemployment problem of less-developed economies is related to income inequality. Consumers have nonhomothetic preferences over differentiated products of formal-sector goods and thus inequality affects the composition of aggregate demand via the price-setting behavior of firms. We find that high inequality divides the formal sector into mass producers and exclusive producers (which serve only the rich); high inequality generates an equilibrium where many workers are crowded into the informal economy; and an increase in subsistence productivity raises the unskilled workers' wages and boosts employment due to the higher purchasing power of poorer households. (JEL D31, D43, E24, E26, J24)

EXACT AND SUPERLATIVE PRICE AND QUANTITY INDICATORS

The traditional economic approach to index number theory is based on a ratio of cost functions. Diewert defined superlative price and quantity indices as observable indices that were exact for a ratio of unit cost functions or for a ratio of linearly homogeneous utility functions. The present paper looks for counterparts to his results in the difference context, for both flexible homothetic and flexible nonhomothetic preferences. The Bennet indicators of price and quantity change turn out to be superlative for the nonhomothetic case. The underlying preferences are of the translation-homothetic form discussed by Balk, Chambers, Dickenson, Färe, and Grosskopf.