We estimate productivities at the sector level for 72 countries and 5 decades, and examine how they evolve over time in both developed and developing countries. In both country groups, comparative advantage has become weaker: productivity grew systematically faster in sectors that were initially...

This paper investigates the welfare gains from European trade integration, and the role of comparative advantage in determining the magnitude of those gains. We use a multisector Ricardian model implemented on 79 countries, and compare welfare in the 2000s to a counterfactual scenario in which...

This paper uses a database covering the universe of French firms for the period 1990--2007 to provide a forensic account of the role of individual firms in generating aggregate fluctuations. We set up a simple multi-sector model of heterogeneous firms selling to multiple markets to motivate a...

This paper evaluates the global welfare impact of observed levels of migration using a quantitative multi-sector model of the world economy calibrated to aggregate and firm-level data. Our framework features cross-country labor productivity differences, international trade, remittances, and a...

We propose a novel identification scheme for a non-technology business cycle shock, that we label "sentiment." This is a shock orthogonal to identified surprise and news TFP shocks that maximizes the short-run forecast error variance of an expectational variable, alternatively a GDP forecast or...

Less developed countries tend to experience higher output volatility, a fact that is, in part, explained by their specialization in more volatile sectors. This paper proposes theoretical explanations for this pattern of specialization -- with the complexity of the goods playing a central role....

Firm size follows Zipf's Law, a very fat-tailed distribution that implies a few large firms account for a disproportionate share of overall economic activity. This distribution of firm size is crucial for evaluating the welfare impact of economic policies such as barriers to entry or trade...

This paper analyzes the impact of international trade on the quality of institutions, such as contract enforcement, property rights, or investor protection. It presents a model in which imperfect institutions create rents for some parties within the economy, and are a source of comparative...

This paper proposes a new mechanism by which country size and international trade affect macroeconomic volatility. We study a multi-country, multi-sector model with heterogeneous firms that are subject to idiosyncratic firm-specific shocks. When the distribution of firm sizes follows a power law...

One of the most striking aspects of the recent recession is the collapse in international trade. This paper uses disaggregated data on U.S. imports and exports to shed light on the anatomy of this collapse. We find that the recent reduction in trade relative to overall economic activity is far...