Knowledge that Transforms

As normally measured, “global inequality” is the relative inequality of incomes found among all people in the world no matter where they live. Francois Bourguignon and Branko Milanovic have written insightful and timely books on global inequality, emphasizing the role of globalization. The books are complementary: Milanovic provides an ambitious broad-brush picture, with some intriguing hypotheses on the processes at work; Bourguignon provides a deep and suitably qualified economic analysis. This paper questions the thesis of both books—that globalization has been a major driving force of inequality between or within countries. The paper also questions the robustness of the evidence for declining global inequality, and notes some conceptual limitations of standard measures in capturing the concerns of many observers in the ongoing debates about globalization and the policy responses. ( JEL D31, D63, E25, F61, F63)

Research in international trade has changed dramatically over the last twenty years, as attention has shifted from countries and industries towards the firms actually engaged in international trade. The now-standard heterogeneous firm model posits measure-zero firms that compete under monopolistic competition and decide whether to export to foreign markets. However, much of international trade is dominated by a few “global firms,” which participate in the international economy along multiple margins and account for substantial shares of aggregate trade. We develop a new theoretical framework that allows firms to have large market shares and decide simultaneously on the set of production locations, export markets, input sources, products to export, and inputs to import. Using US firm and trade transactions data, we provide strong evidence in support of this framework's main predictions of interdependencies and complementarities between these margins of firm international participation. Global firms participate more intensively along each margin, magnifying the impact of underlying differences in firm characteristics and increasing their shares of aggregate trade. (JEL D22, F14, F23, L60, R32)

A growing experimental literature studies the determinants of cooperation in infinitely repeated games, tests different predictions of the theory, and suggests an empirical solution to the problem of multiple equilibria. To provide a robust description of the literature's findings, we gather and analyze a metadata set of experiments on infinitely repeated prisoner's dilemma games. The experimental data show that cooperation is affected by infinite repetition and is more likely to arise when it can be supported in equilibrium. However, the fact that cooperation can be supported in equilibrium does not imply that most subjects will cooperate. High cooperation rates will emerge only when the parameters of the repeated game are such that cooperation is very robust to strategic uncertainty. We also review the results regarding the effect of imperfect monitoring, changing partners, and personal characteristics on cooperation and the strategies used to support it. (JEL C71, C73, D81, D83)

Invariably, across a cross-section of countries and time periods, wealth distributions are skewed to the right displaying thick upper tails, that is, large and slowly declining top wealth shares. In this survey, we categorize the theoretical studies on the distribution of wealth in terms of the underlying economic mechanisms generating skewness and thick tails. Further, we show how these mechanisms can be micro-founded by the consumption–savings decisions of rational agents in specific economic and demographic environments. Finally we map the large empirical work on the wealth distribution to its theoretical underpinnings. (JEL C46, D14, D31, E21, J31)

This paper argues for a careful (re)consideration of the expectations formation process and a more systematic inclusion of real-time expectations through survey data in macroeconomic analyses. While the rational expectations revolution has allowed for great leaps in macroeconomic modeling, the surveyed empirical microevidence appears increasingly at odds with the full-information rational expectation assumption. We explore models of expectation formation that can potentially explain why and how survey data deviate from full-information rational expectations. Using the New Keynesian Phillips curve as an extensive case study, we demonstrate how incorporating survey data on inflation expectations can address a number of otherwise puzzling shortcomings that arise under the assumption of full-information rational expectations. (JEL D04, E24, E27, E31, E37)

There is growing interest in enhancing research transparency and reproducibility in economics and other scientific fields. We survey existing work on these topics within economics and discuss the evidence suggesting that publication bias, inability to replicate, and specification searching remain widespread in the discipline. We next discuss recent progress in this area, including through improved research design, study registration and pre-analysis plans, disclosure standards, and open sharing of data and materials, drawing on experiences in both economics and other social sciences. We discuss areas where consensus is emerging on new practices, as well as approaches that remain controversial, and speculate about the most effective ways to make economics research more credible in the future. ( JEL A11, C18, I23)

Understanding whether labor market discrimination explains inferior labor market outcomes for many groups has drawn the attention of labor economists for decades— at least since the publication of Gary Becker’s The Economics of Discrimination in 1957. The decades of research on discrimination in labor markets began with a regression-based “decomposition” approach, asking whether raw wage or earnings differences between groups—which might constitute prima facie evidence of discrimination—were in fact attributable to other productivity-related factors. Subsequent research—responding in large part to limitations of the regression-based approach—moved on to other approaches, such as using firm-level data to estimate both marginal productivity and wage differentials. In recent years, however, there has been substantial growth in experimental research on labor market discrimination—although the earliest experiments were done decades ago. Some experimental research on labor market discrimination takes place in the lab. But far more of it is done in the field, which makes this particular area of experimental research unique relative to the explosion of experimental economic research more generally. This paper surveys the full range of experimental literature on labor market discrimination, places it in the context of the broader research literature on labor market discrimination, discusses the experimental literature from many different perspectives (empirical, theoretical, and policy), and reviews both what this literature has taught us thus far, and what remains to be done. (JEL C93, J14, J15, J16, J23, J41, J71)

That prenatal events can have life-long consequences is now well established. Nevertheless, research on the fetal origins hypothesis is flourishing and has expanded to include the early childhood (postnatal) environment. Why does this literature have a “second act?” We summarize the major themes and contributions driving the empirical literature since our 2011 reviews, and try to interpret the literature in light of an overarching conceptual framework about how human capital is produced early in life. One major finding is that relatively mild shocks in early life can have substantial negative impacts, but that the effects are often heterogeneous reflecting differences in child endowments, budget constraints, and production technologies. Moreover, shocks, investments, and interventions can interact in complex ways that are only beginning to be understood. Many advances in our knowledge are due to increasing accessibility of comprehensive administrative data that allow events in early life to be linked to long-term outcomes. Yet, we still know relatively little about the interval between, and thus about whether it would be feasible to identify and intervene with affected individuals at some point between early life and adulthood. We do know enough, however, to be able to identify some interventions that hold promise for improving child outcomes in early life and throughout the life course. (JEL I12, J13, J16, Q51, Q53)