Annual Review of Economics - Volume 13, 2021

Undoubtedly one of the best economists of his generation, Emmanuel Farhi transformed the theories of taxation, macroeconomics, and international finance. This essay describes his itinerary and his research style and attempts to pay tribute to his immense contribution to economics.

Modern trade agreements no longer emphasize basic trade liberalization but instead focus on international policy coordination in a much broader sense. In this review we introduce the emerging literature on the political economy of such deep integration agreements. We organize our discussion around three main points. First, the political conflict surrounding trade agreements is moving beyond the classic antagonism of exporter interests who gain from trade and import-competing interests who lose from trade. Second, there is a more intense popular backlash against deep integration agreements than there was against shallow integration agreements. Finally, the welfare economics of trade agreements has become more complex, in the sense that the goal of achieving freer trade is no longer sufficient as a guide to evaluating the efficiency of international agreements.

This review focuses on properties related to the robustness and stability of Nash equilibria in games with a large number of players. Somewhat surprisingly, these equilibria become substantially more robust and stable as the number of players increases. We illustrate the relevant phenomena through a binary-action game with strategic substitutes, framed as a game of social isolation in a pandemic environment.

Voters have strong incentives to increase their influence by trading votes, acquiring others’ votes when preferences are strong in exchange for giving votes away when preferences are weak. But is vote trading welfare improving or welfare decreasing? For a practice long believed to be central to collective decisions, the lack of a clear answer is surprising. We review the theoretical literature and, when available, its related experimental tests. We begin with the analysis of logrolling, the exchange of votes for votes. We then focus on vote markets, where votes can be traded against a numeraire. We conclude with procedures allowing voters to shift votes across decisions—that is, allowing one to trade votes with oneself only. We find that vote trading and vote markets are typically inefficient; more encouraging results are obtained by allowing voters to allocate votes across decisions.

In representative democracies, a variety of rules are employed to select and retain public officials to reflect public preferences over policies. We discuss the literature on selection and retention rules for government officials, focusing on low-information offices. First, we overview the historical origins and the scope of the variation in selection and retention rules. Second, we provide conceptual frameworks for assessing the advantages and disadvantages of direct elections and discuss various factors that influence the functioning of elections. Third, we present empirical regularities. We summarize the baseline effects of the institutional variation and their interaction with factors such as media and compensation. Finally, we discuss outstanding questions on theoretical and empirical fronts, and how the digitization of government information and advances in machine learning can open up new avenues for research.

This article reviews the literature on civil conflict and development with a focus on the socioeconomic consequences of violence and on promising policies for fostering peace. We make four main points. First, one of the reasons conflict is still often overlooked as key factor for development is that conflict costs are typically underestimated, in particular the shadow costs of deterrence. Second, there are several types of war traps that hold countries back, both economically and politically. Third, to break these traps, policies must be calibrated to address jointly both poverty and social tensions, as there is a strong macro complementarity between peace and development objectives. We document how single-minded policies that ignore this dual challenge can spectacularly fail, and we discuss in depth a series of particularly promising policies. Fourth, we highlight the increasing potential of novel data collection methodologies and the need for policy evaluation tools in violent contexts.

There is compelling evidence that globalization shocks, often working through culture and identity, have played an important role in driving up support for populist movements, particularly of the right-wing kind. I start with an empirical analysis of the 2016 presidential election in the United States to show that globalization-related attitudinal variables were important correlates of the switch to Trump. I then provide a conceptual framework that identifies four distinct channels through which globalization can stimulate populism, two each on the demand and supply sides of politics. I evaluate the empirical literature with the help of this framework, discussing trade, financial globalization, and immigration separately. I conclude the review by discussing some apparently anomalous cases in which populists have been against, rather than in favor of, trade protection.

We provide an overview of the relationship between financial networks and systemic risk. We present a taxonomy of different types of systemic risk, differentiating between direct externalities between financial organizations (e.g., defaults, correlated portfolios, fire sales), and perceptions and feedback effects (e.g., bank runs, credit freezes). We also discuss optimal regulation and bailouts, measurements of systemic risk and financial centrality, choices by banks regarding their portfolios and partnerships, and the changing nature of financial networks.

Countries are making more active use of macroprudential tools than in the past with the goal of improving the resilience of their broader financial systems. A growing body of evidence suggests that these tools can accomplish specific domestic goals and should reduce a country's vulnerability to many domestic and international shocks. The evidence also suggests, however, that these policies are not an elixir. They will not insulate economies from volatility, and they generate leakages to the nonbank financial system and spillovers through international borrowing, lending, and other cross-border exposures. Some of these unintended consequences can mitigate the effectiveness of macroprudential policies and generate new vulnerabilities and risks. The COVID-19 crisis provides a lens to evaluate the effectiveness of current macroprudential regulations during a period of extreme market volatility and economic stress. The experience to date suggests that macroprudential tools provide some benefits and should remain a focus of macroeconomic policy, but with realistic expectations about what they can accomplish.

We review the current state of the estimation of dynamic stochastic general equilibrium (DSGE) models. After introducing a general framework for dealing with DSGE models, the state-space representation, we discuss how to evaluate moments or the likelihood function implied by such a structure. We discuss, in varying degrees of detail, recent advances in the field, such as the tempered particle filter, approximated Bayesian computation, Hamiltonian Monte Carlo, variational inference, and machine learning. These methods show much promise but have not been fully explored by the DSGE community yet. We conclude by outlining three future challenges for this line of research.

We review the literature that studies the dynamics of firms in foreign markets, at both the intensive and extensive margins, and their aggregate implications. We first summarize a set of micro facts on exporter entry, expansion, contraction, and exit and several macro facts about the response of aggregate trade flows to trade-policy and business-cycle shocks. We then present the canonical model developed to account for these facts and discuss its connection to the empirical evidence. We show how three model features—future uncertain profits, an investment in market access, and high depreciation of that access upon exit—generate transition dynamics and long-run aggregate outcomes from a cut in tariffs. The model and its extensions contribute to our understanding of trade integration and the evolution of future trade barriers. We discuss the key challenges faced by the canonical model, its possible extensions, and applications of the framework to recent global events.

This article reviews the literature on currency and country risk with a focus on their macroeconomic origins and implications. A growing body of evidence shows that countries with safer currencies enjoy persistently lower interest rates and a lower required return to capital. As a result, they accumulate relatively more capital than countries with currencies that international investors perceive as risky. Whereas earlier research focused mainly on the role of currency risk in generating violations of uncovered interest parity and other financial anomalies, more recent evidence points to important implications for the allocation of capital across countries, the efficacy of exchange rate stabilization policies, the sustainability of trade deficits, and the spillovers of shocks across international borders.

This article reviews recent developments in the study of firm and industry dynamics, with a special emphasis on the econometric endogeneity of market structure. The endogeneity of market structure follows from the presence of serially correlated unobservable shocks to the profitability of firms’ dynamic decisions, a feature common to many empirical settings. Methods that ignore endogeneity can lead to misleading parameter estimates and misleading counterfactual results. We pay particular attention to extensions of standard two-step methods that leverage instrumental variables to address endogeneity in both single-agent and oligopoly models. A first step set-identifies dynamic policy functions together with serial correlation parameters, and a second step quickly solves for profit function parameters using an extension of existing forward-simulation methods. We discuss how these new methods provide a general solution to initial-conditions problems and how they can yield practical estimation strategies.

I review the literature on financial speculation driven by belief disagreements from a macroeconomics perspective. To highlight unifying themes, I develop a stylized macroeconomic model that embeds several mechanisms. With short-selling constraints, speculation can generate overvaluation and speculative bubbles. Leverage can substantially inflate speculative bubbles, and leverage limits depend on perceived downside risks. Shifts in beliefs about downside tail scenarios can explain the emergence and the collapse of leveraged speculative bubbles. Speculative bubbles are related to rational bubbles, but they match better the empirical evidence on the predictability of asset returns. Even without short-selling constraints, speculation induces procyclical asset valuation. When speculation affects the price of aggregate assets, it also influences macroeconomic outcomes such as aggregate consumption, investment, and output. Speculation in the boom years reduces asset prices, aggregate demand, and output in the subsequent recession. Macroprudential policies that restrict speculation in the boom can improve macroeconomic stability and social welfare.

We live in a world filled with uncertainty. In this essay, I show that featuring this phenomenon more in economic analyses adds to our understanding of how financial markets work and how best to design prudent economic policy. This essay explores methods that allow for a broader conceptualization of uncertainty than is typical in economic investigations. These methods draw on insights from decision theory to engage in uncertainty quantification and sensitivity analysis. Uncertainty quantification in economics differs from uncertainty quantification in most sciences because there is uncertainty from the perspective both of an external observer and of people and enterprises within the model. I illustrate these methods in two example economies in which the understanding of long-term growth is limited. One example looks at uncertainty ramifications for fluctuations in financial markets, and the other considers the prudent design of policy when the quantitative magnitude of climate change and its impact on economic opportunities are unknown.

This review considers conceptual issues underlying empirical work on markets. It is divided in three parts. The first part reviews the analysis of demand and equilibrium in retail markets and then considers recent advances in the analysis of markets that require different assumptions: markets where adverse selection and moral hazard may be important, vertical markets with bargaining, and markets wherein a centralized allocation mechanism replaces prices. The second part considers the analysis of cost and production. It reviews the simultaneity and selection issues in production function estimation and then considers the distinction between revenue- and quantity-generating functions and its implications for the analysis of markups, as well as the empirical analysis of fixed costs and its implications for the analysis of product repositioning. The review concludes by considering issues that arise due to the complexity of the empirical analysis of market dynamics and appropriate ways of dealing with them.

The real exchange rate (RER) measures relative price levels across countries, capturing deviations from purchasing power parity (PPP). RER is a key variable in international macroeconomic models as it is central to equilibrium conditions in both goods and asset markets. It is also one of the most starkly behaving variables empirically, tightly comoving with the nominal exchange rate and virtually uncorrelated with most other macroeconomic variables, nominal or real. This review lays out an equilibrium framework of RER determination, focusing separately on each building block and discussing corresponding empirical evidence. We emphasize home bias and incomplete pass-through into prices with expenditure switching and goods market clearing, imperfect international risk sharing, country budget constraint, and monetary policy regime. We show that RER is inherently a general equilibrium variable that depends on the full model structure and policy regime, and therefore partial theories like PPP are insufficient to explain it. We also discuss issues of stationarity and predictability of exchange rates.

Should choice be offered in social insurance programs? This review presents a conceptual framework that identifies the key forces determining the social value of offering choice. We show that the value of offering choice is higher the larger the variation in individual valuations for extra insurance is, but it gets reduced by both selection on risk and selection on moral hazard. Besides adverse selection, the implementation of choice-based policies is further challenged by the presence of choice frictions or the obligation to offer basic uncompensated care. All these inefficiencies can be seen as externalities that do not rationalize the absence of providing choice per se but point to the need for regulatory policies and suggest the potential value of corrective pricing à la Pigou. Applying this framework to the existing evidence on these forces in the context of unemployment insurance, we find that offering insurance choice can be valuable even in the presence of significant adverse selection. We conclude by showing how this framework can constitute a fruitful guide for further empirical research in different insurance domains.

This article reviews recent developments in the econometrics of early childhood human capital and investments. We start with a discussion about the lack of cardinality in test scores, the reasons it matters for empirical research on human capital, and the approaches researchers have used to address this problem. Next, we discuss how the literature has accounted for the errors in human capital measurements and investments. Then, we focus on the estimation of production functions of human capital. We present two different specifications of the production function and discuss when to use one versus the other. We describe how researchers have addressed cardinality, measurement errors, and endogeneity of inputs to estimate the technology of skill formation. Finally, we take stock of the work to date, and we identify opportunities for new research directions in this field.

This article reviews and generalizes the sufficient statistics approach to policy evaluation. The idea of the approach is that the welfare effect of policy changes can be expressed in terms of estimable reduced-form elasticities, allowing for policy evaluation without estimating the structural primitives of fully specified models. The approach relies on three assumptions: that policy changes are small, that government policy is the only source of market imperfection, and that a set of high-level restrictions on the environment and on preferences can be used to reduce the number of elasticities to be estimated. We generalize the approach in all three dimensions. It is possible to develop transparent sufficient statistics formulas under very general conditions, but the estimation requirements increase greatly. Starting from such general formulas elucidates that feasible empirical implementations are in fact structural approaches.