We establish five facts about the informal economy in developing countries. First, it is huge, reaching about half of the total in the poorest countries. Second, it has extremely low productivity compared to the formal economy: informal firms are typically small, inefficient, and run by poorly...

Tracking individual workers across jobs after Brazil's trade liberalization in the 1990s shows that tariff cuts trigger worker displacements, but neither exporters nor comparative-advantage sectors absorb trade-displaced labor. On the contrary, exporters separate from significantly more and hire...

In developing countries, informal firms (those that are not registered with the government) account for about half of all economic activity. We consider three broad views of the role of such firms in economic development. According to the romantic view, these firms would become the engine of...

This paper investigates the determinants of informal economic activity. We present two equilibrium models of informality and test their implications using a survey of 48,000+ small firms in Brazil. We define informality as tax avoidance; firms in the informal sector avoid tax payments but suffer...

Growth and structural transformation of the manufacturing sector in developing countries are generally considered to be the result of the expansion of the "modem" (large-scale) sector relative to the "traditional" (small-scale) sector. Examining the sources of labor productivity growth in...

The evolution of inequality in permanent income is investigated during the course of a less developed country's transformation from a primarily agricultural to a primarily urban-industrial economy. The source of inequality is market luck in obtaining employment in the protected urban "formal...

This paper introduces contemporaneously available monetary data into an "equilibrium" model that combines rational expectations, market clearing, and incomplete information about monetary disturbances. Data on the current money stock involve a preliminary estimate that is subject to a subsequent...

This chapter surveys new data sources employed in urban and regional economics in the past decade and the insights they have enabled. We first provide a primer on the data sources, including advantages, disadvantages and use cases. Historical data sources include linked census records as well as...

How beneficial are transport infrastructure investments and other transport policies? This chapter develops a framework whose goal is to survey and synthesize the answers that regional and urban economists have given to this question. Emphasis is placed on theoretical results about sufficient...

New, "big" data sources allow measurement of city characteristics and outcome variables higher frequencies and finer geographic scales than ever before. However, big data will not solve large urban social science questions on its own. Big data has the most value for the study of cities when it...