Graciela Laura Kaminsky
This article examines the new trends in research on capital flows fueled by the 2007–2009 Global Crisis. Previous studies on capital flows focused on current account imbalances and net capital flows. The Global Crisis changed that. The onset of this crisis was preceded by a dramatic increase in gross financial flows while net capital flows remained mostly subdued. The attention in academia zoomed in on gross inflows and outflows with special attention to cross-border banking flows before the crisis erupted and the shift towards corporate bond issuance in its aftermath. The boom and bust in capital flows around the Global Crisis also stimulated a new area of research: capturing the “global factor.” This research adopts two different approaches. The traditional literature on the push–pull factors, which before the crisis was mostly focused on monetary policy in the financial center as the “push factor,” started to explore what other factors contribute to the co-movement of capital flows as well as to amplify the role of monetary policy in the financial center on capital flows. This new research focuses on global banks’ leverage, risk appetite, and global uncertainty. Since the “global factor” is not known, a second branch of the literature has captured this factor indirectly using dynamic common factors extracted from actual capital flows or movements in asset prices.
Alessandro Rebucci and Chang Ma
This paper reviews selected post–Global Financial Crisis theoretical and empirical contributions on capital controls and identifies three theoretical motives for the use of capital controls: pecuniary externalities in models of financial crises, aggregate demand externalities in New Keynesian models of the business cycle, and terms of trade manipulation in open-economy models with pricing power. Pecuniary and demand externalities offer the most compelling case for the adoption of capital controls, but macroprudential policy can also address the same distortions. So capital controls generally are not the only instrument that can do the job. If evaluated through the lenses of the new theories, the empirical evidence reviewed suggests that capital controls can have the intended effects, even though the extant literature is inconclusive as to whether the effects documented amount to a net gain or loss in welfare terms. Terms of trade manipulation also provides a clear-cut theoretical case for the use of capital controls, but this motive is less compelling because of the spillover and coordination issues inherent in the use of control on capital flows for this purpose. Perhaps not surprisingly, only a handful of countries have used capital controls in a countercyclical manner, while many adopted macroprudential policies. This suggests that capital control policy might entail additional costs other than increased financing costs, such as signaling the bad quality of future policies, leakages, and spillovers.
Anthony J. Venables
Economic activity is unevenly distributed across space, both internationally and within countries. What determines this spatial distribution, and how is it shaped by trade? Classical trade theory gives the insights of comparative advantage and gains from trade but is firmly aspatial, modeling countries as points and trade (in goods and factors of production) as either perfectly frictionless or impossible. Modern theory places this in a spatial context in which geographical considerations influence the volume of trade between places. Gravity models tell us that distance is important, with each doubling of distance between places halving the volume of trade. Modeling the location decisions of firms gives a theory of location of activity based on factor costs (as in classical theory) and also on proximity to markets, proximity to suppliers, and the extent of competition in each market. It follows from this that—if there is a high degree of mobility—firms and economic activity as a whole may tend to cluster, providing an explanation of observed spatial unevenness. In some circumstances falling trade barriers may trigger the deindustrialization of some areas as activity clusters in fewer places. In other circumstances falling barriers may enable activity to spread out, reducing inequalities within and between countries. Research over the past several decades has established the mechanisms that cause these changes and placed them in full general equilibrium models of the economy. Empirical work has quantified many of the important relationships. However, geography and trade remains an area where progress is needed to develop robust tools that can be used to inform place-based policies (concerning trade, transport, infrastructure, and local economic development), particularly in view of the huge expenditures that such policies incur.
The uncovered interest parity (UIP) condition states that the interest rate differential between two currencies is the expected rate of change of their exchange rate. Empirically, however, in the 1976–2018 period, exchange rate changes were approximately unpredictable over short horizons, with a slight tendency for currencies with higher interest rates to appreciate against currencies with lower interest rates. If the UIP condition held exactly, carry trades, in which investors borrow low interest rate currencies and lend high interest rate currencies, would earn zero average profits. The fact that UIP is violated, therefore, is a necessary condition to explain the fact that carry trades earned significantly positive profits in the 1976–2018 period. A large literature has documented the failure of UIP, as well as the profitability of carry trades, and is surveyed here. Additionally, summary evidence is provided here for the G10 currencies. This evidence shows that carry trades have been significantly less profitable since 2007–2008, and that there was an apparent structural break in exchange rate predictability around the same time.
A large theoretical literature explores economic explanations of this phenomenon and is briefly surveyed here. Prominent among the theoretical models are ones based on risk aversion, peso problems, rare disasters, biases in investor expectations, information frictions, incomplete financial markets, and financial market segmentation.
Difei Geng and Kamal Saggi
Foreign direct investment (FDI) plays an important role in facilitating the process of international technology diffusion. While FDI among industrialized countries primarily occurs via international mergers and acquisitions (M&As), investment headed to developing countries is more likely to be greenfield in nature; that is, it involves the establishment or expansion of new foreign affiliates by multinational firms. M&As have the potential to yield productivity improvements via changes in management and organization structure of target firms, whereas greenfield FDI leads to transfer of novel technical know-how by initiating the production of new products in host countries as well as by introducing improvements in existing production processes.
Given the prominent role that multinational firms play in global research and development (R&D), there is much interest in whether and how technologies transferred by them to their foreign subsidiaries later diffuse more broadly in host economies, thereby potentially generating broad-based productivity gains. Empirical evidence shows that whereas spillovers from FDI to competing local firms are elusive, such is not the case for spillovers to local suppliers and other agents involved in vertical relationships with multinationals. Multinationals have substantially increased their investments in research facilities in various parts of the world and in R&D collaboration with local firms in developing countries, most notably China and India. Such international collaboration in R&D spearheaded by multinational firms has the potential to accelerate global productivity growth.
The geography of economic activity refers to the distribution of population, production, and consumption of goods and services in geographic space. The geography of growth and development refers to the local growth and decline of economic activity and the overall distribution of these local changes within and across countries. The pattern of growth in space can vary substantially across regions, countries, and industries. Ultimately, these patterns can help explain the role that spatial frictions (like transport and migration costs) can play in the overall development of the world economy.
The interaction of agglomeration and congestion forces determines the density of economic activity in particular locations. Agglomeration forces refer to forces that bring together agents and firms by conveying benefits from locating close to each other, or for locating in a particular area. Examples include local technology and institutions, natural resources and local amenities, infrastructure, as well as knowledge spillovers. Congestion forces refer to the disadvantages of locating close to each other. They include traffic, high land prices, as well as crime and other urban dis-amenities. The balance of these forces is mediated by the ability of individuals, firms, good and services, as well as ideas and technology, to move across space: namely, migration, relocation, transport, commuting and communication costs. These spatial frictions together with the varying strength of congestion and agglomeration forces determines the distribution of economic activity. Changes in these forces and frictions—some purposefully made by agents given the economic environment they face and some exogenous—determine the geography of growth and development.
The main evolution of the forces that influence the geography of growth and development have been changes in transport technology, the diffusion of general-purpose technologies, and the structural transformation of economies from agriculture, to manufacturing, to service-oriented economies. There are many challenges in modeling and quantifying these forces and their effects. Nevertheless, doing so is essential to evaluate the impact of a variety of phenomena, from climate change to the effects of globalization and advances in information technology.
Pao-Li Chang and Wen-Tai Hsu
This article reviews interrelated power-law phenomena in geography and trade. Given the empirical evidence on the gravity equation in trade flows across countries and regions, its theoretical underpinnings are reviewed. The gravity equation amounts to saying that trade flows follow a power law in distance (or geographic barriers). It is concluded that in the environment with firm heterogeneity, the power law in firm size is the key condition for the gravity equation to arise. A distribution is said to follow a power law if its tail probability follows a power function in the distribution’s right tail. The second part of this article reviews the literature that provides the microfoundation for the power law in firm size and reviews how this power law (in firm size) may be related to the power laws in other distributions (in incomes, firm productivity and city size).
Sushant Acharya and Paolo Pesenti
Global policy spillovers can be defined as the effect of policy changes in one country on economic outcomes in other countries. The literature has mainly focused on monetary policy interdependencies and has identified three channels through which policy spillovers can materialize. The first is the expenditure-shifting channel—a monetary expansion in one country depreciates its currency, making its goods cheaper relative to those in other countries and shifting global demand toward domestic tradable goods. The second is the expenditure-changing channel—expansionary monetary policy in one country raises both domestic and foreign expenditure. The third is the financial spillovers channel—expansionary monetary policy in one country eases financial conditions in other economies. The literature generally finds that the net transmission effect is positive but small. However, estimated spillovers vary widely across countries and over time. In the aftermath of the Great Recession, the policy debate has devoted special attention to the possibility that the magnitude and sign of international spillovers might have changed in an environment of low interest rates worldwide, as the expenditure-shifting channel becomes more relevant when the effective lower bound reduces the effectiveness of conventional monetary policies.
Scott Baier and Samuel Standaert
The gravity model of international trade states that the volume of trade between two countries is proportional to their economic mass and a measure of their relative trade frictions. Perhaps because of its intuitive appeal, the gravity model has been the workhorse model of international trade for more than 50 years. While the initial empirical work using the gravity model lacked sound theoretical underpinnings, the theoretical developments have highlighted how a gravity-like specification can be derived from many models with varying assumptions about preferences, technology, and market structure. Along the strengthening of the theoretical roots of the gravity model, the way in which it is estimated has also evolved significantly since the start of the new millennium. Depending on the exact characteristics of regression, different estimation methods should be used to estimate the gravity model.
While the modern theory of international trade allows for many different modeling assumptions, the gains from trade can often be calculated using a common set of statistics. In particular, the share of a country’s output that is consumed domestically, the elasticity of bilateral trade with respect to trade costs, and the relationship between markups and firm size, each have a clear role in the gains from integration. All of these statistics may also be structurally linked to the degree of firm heterogeneity, usually the dispersion in firm-level productivity. Accordingly, the presence of firm heterogeneity may have a meaningful impact on the welfare response to trade liberalization. A quantitative application of a common firm heterogeneity model indicates that increased dispersion of firm-level productivity has a disproportionately large and positive impact on the gains from trade for smaller, less-developed countries.
Home bias in international macroeconomics refers to the fact that investors around the world tend to allocate majority of their portfolios into domestic assets, despite the potential benefits to be had from international diversification. This phenomenon has been occurring across countries, over time, and across equity or bond portfolios. The bias towards domestic assets tends to be larger in developing countries relative to developed economies, with Europe characterized by the lowest equity home bias, while Central and South America—by the highest equity home bias. In addition, despite the secular decline in the level of equity home bias over time in all countries and regions, home bias still remains a robust feature of the data.
Whether home bias is a puzzle depends on the portfolio allocation that one uses as a theoretical benchmark. For instance, home bias in equity portfolio is a puzzle when assessed through the lens of a simple international capital asset pricing model (CAPM) with homogeneous investors. This model predicts that investors should hold world market portfolios, namely a portfolio with the share of domestic asset equal to the share of those assets in the world market portfolio. For instance, since the share of US equity in the world capitalization in 2016 was 56%, then US investors should allocate 56% of their equity portfolio into local assets, while investing the remaining 44% into foreign equities. Instead, foreign equity comprised just 23% of US equity portfolio in 2016, hence the equity home bias.
Alternative portfolio benchmark comes from the theories that emphasize costs for trading assets in international financial markets. These include transaction and information costs, differential tax treatments, and more broadly, differences in institutional environments. This research, however, has so far been unable to reach a consensus on the explanatory power of such costs.
Yet another theory argues that equity home bias can arise due to the hedging properties of local equity. In particular, local equity can provide insurance from real exchange rate risk and non-tradable income risk (such as labor income risk), and thus a preference towards home equities is not a puzzle, but rather an optimal response to such risks.
These theories, main advances and results in the macroeconomic literature on home bias are discussed in this article. It starts by presenting some empirical facts on the extent and dynamics of equity home bias in developed and developing countries. It is then shown how home bias can arise as an equilibrium outcome of the hedging demand in the model with real exchange rate and non-tradable labor income risk. Since solving models with portfolio choice is challenging, the recent advances in solving such models are also outlined in this article.
Integrating the portfolio dynamics into models that can generate realistic asset price and exchange rate dynamics remains a fruitful avenue for future research. A discussion of additional open questions in this research agenda and suggestions for further readings are also provided.
Eduardo A. Cavallo
Sudden stops in capital flows are a form of financial whiplash that creates instability and crises in the affected economies. Sudden stops in net capital flows trigger current account reversals as countries that were borrowing on net from the rest of the world before the stop can no longer finance current account deficits. Sudden stops in gross capital flows are associated with financial instability, especially when the gross flows are dominated by volatile cross-border banking flows. Sudden stops in gross and net capital flows are episodes with an external trigger. This implies that the spark that ignites sudden stops originates outside the affected country: more specifically, in the supply of foreign financing that can halt for reasons that may be unrelated to the affected country’s domestic conditions. Yet a spark cannot generate a fire unless combustible materials are around. The literature has established that a set of domestic macroeconomic fundamentals are the combustible materials that make some countries more vulnerable than others. Higher fiscal deficits, larger current account deficits, and higher levels of foreign currency debts in the domestic financial system are manifestations of weak fundamentals that increase vulnerability. Those same factors increase the costs in terms of output losses when the crisis materializes. On the flip side, international reserves provide buffers that can help countries offset the risks. Holding foreign currency reserves hedges the fiscal position of the government providing it with more resources to respond to the crisis. While it may be impossible for countries to completely insulate themselves from the volatility of capital inflows, the choice of antidotes to prevent that volatility from forcing potentially costly external adjustments is in their own hands. The global financial architecture can be improved to support those efforts if countries could agree on and fund a more powerful international lender of last resort that resembles, at the global scale, the role of the Federal Reserve Bank in promoting financial stability in the United States.
Ehsan U. Choudhri
Exchange rates often display sudden and large changes. There is considerable interest in examining how these changes affect prices, especially import and consumer prices. Exchange rate pass-through measures the responsiveness of the price of a basket of goods to changes in the exchange rate and is defined as the elasticity of the price of the basket (expressed in home currency) with respect to the exchange rate (defined as the price of foreign currency). The pass-through estimates vary across product groups, countries, and time periods, but a general finding is that pass-through tends to be significantly less than one, which implies that prices do not fully respond to a foreign currency appreciation. Pass-through to export prices tends to be smaller than pass-through to import prices. Pass-through to consumer prices is lower than both import and export price pass-through and is generally very small. One explanation of pass-through evidence focuses on the role of nominal rigidities (infrequent changes in prices set in home or foreign currency). Another explanation emphasizes the importance of markup variation in response to exchange rate changes.
In models with nominal rigidities, one important issue is whether exporting firms set prices in their country’s currency (producer’s currency) or importing country’s currency (consumer’s currency). If prices are sticky in producer’s currency, flexible exchange rates are preferable as they allow for desirable relative price adjustment. On the other hand, if prices are sticky in consumer’s currency, exchange rate flexibility is not as helpful in adjusting prices and fixed exchange rates are superior. The standard model where markup is constant and all firms (at home and abroad) use either producer or consumer currency pricing is not consistent with typical estimates of pass-through to import and export prices. To explain this evidence, the standard model needs to be modified to allow for variable markup and/or a hybrid model of currency choice where some firms set prices in producer’s and others in consumer’s currency. In the case of the hybrid model, the welfare difference between fixed and flexible exchange rates is not as stark as in the pure cases of currency choice and is likely to be small. Another issue of much interest is whether inflationary environment can affect pass-through, especially to consumer prices. Inflationary environment can influence pass-through to import and consumer prices through several channels, such as persistence of costs and frequency of price change. Empirical evidence shows that pass-through to consumer prices is related to the level and variability of inflation across countries and time periods and is lower in an environment with low and stable inflation. This evidence suggests that a monetary policy regime that targets low inflation will produce a low pass-through environment, which would dampen the price effects of exchange rate changes.
The links of international reserves, exchange rates, and monetary policy can be understood through the lens of a modern incarnation of the “impossible trinity” (aka the “trilemma”), based on Mundell and Fleming’s hypothesis that a country may simultaneously choose any two, but not all, of the following three policy goals: monetary independence, exchange rate stability, and financial integration. The original economic trilemma was framed in the 1960s, during the Bretton Woods regime, as a binary choice of two out of the possible three policy goals. However, in the 1990s and 2000s, emerging markets and developing countries found that deeper financial integration comes with growing exposure to financial instability and the increased risk of “sudden stop” of capital inflows and capital flight crises. These crises have been characterized by exchange rate instability triggered by countries’ balance sheet exposure to external hard currency debt—exposures that have propagated banking instabilities and crises. Such events have frequently morphed into deep internal and external debt crises, ending with bailouts of systemic banks and powerful macro players. The resultant domestic debt overhang led to fiscal dominance and a reduction of the scope of monetary policy. With varying lags, these crises induced economic and political changes, in which a growing share of emerging markets and developing countries converged to “in-between” regimes in the trilemma middle range—that is, managed exchange rate flexibility, controlled financial integration, and limited but viable monetary autonomy. Emerging research has validated a modern version of the trilemma: that is, countries face a continuous trilemma trade-off in which a higher trilemma policy goal is “traded off” with a drop in the weighted average of the other two trilemma policy goals. The concerns associated with exposure to financial instability have been addressed by varying configurations of managing public buffers (international reserves, sovereign wealth funds), as well as growing application of macro-prudential measures aimed at inducing systemic players to internalize the impact of their balance sheet exposure on a country’s financial stability. Consequently, the original trilemma has morphed into a quadrilemma, wherein financial stability has been added to the trilemma’s original policy goals. Size does matter, and there is no way for smaller countries to insulate themselves fully from exposure to global cycles and shocks. Yet successful navigation of the open-economy quadrilemma helps in reducing the transmission of external shock to the domestic economy, as well as the costs of domestic shocks. These observations explain the relative resilience of emerging markets—especially in countries with more mature institutions—as they have been buffered by deeper precautionary management of reserves, and greater fiscal and monetary space.
We close the discussion noting that the global financial crisis, and the subsequent Eurozone crisis, have shown that no country is immune from exposure to financial instability and from the modern quadrilemma. However, countries with mature institutions, deeper fiscal capabilities, and more fiscal space may substitute the reliance on costly precautionary buffers with bilateral swap lines coordinated among their central banks. While the benefits of such arrangements are clear, they may hinge on the presence and credibility of their fiscal backstop mechanisms, and on curbing the resultant moral hazard. Time will test this credibility, and the degree to which risk-pooling arrangements can be extended to cover the growing share of emerging markets and developing countries.
While economists overwhelmingly favor free trade, even unilateral free trade, because of the gains realizable from specialization and the exploitation of comparative advantage, in fact international trading relations are structured by a complex body of multilateral and preferential trade agreements. The article outlines the case for multilateral trade agreements and the non-discrimination principle that they embody, in the form of both the Most Favored Nation principle and the National Treatment principle, where non-discrimination has been widely advocated as supporting both geopolitical goals (reducing economic factionalism) and economic goals (ensuring the full play of theories of comparative advantage undistorted by discriminatory trade treatment).
Despite the virtues of multilateral trade agreements, preferential trade agreements (PTAs), authorized from the outset under GATT, have proliferated in recent years, even though they are inherently discriminatory between members and non-members, provoking vigorous debates as to whether (a) PTAs are trade-creating or trade-diverting; (b) whether they increase transaction costs in international trade; and (c) whether they undermine the future course of multilateral trade liberalization.
A further and similarly contentious derogation from the principle of non-discrimination under the multilateral system is Special and Differential Treatment for developing countries, where since the mid-1950s developing countries have been given much greater latitude than developed countries to engage in trade protectionism on the import side in order to promote infant industries, and since the mid-1960s on the export side have benefited from non-reciprocal trade concessions by developed countries on products of actual or potential export interest to developing countries.
Beyond debates over the strengths and weaknesses of multilateral trade agreements and the two major derogations therefrom, further debates surround the appropriate scope of trade agreements, and in particular the expansion of their scope in recent decades to address divergences or incompatibilities across a wide range of domestic regulatory and related policies that arguably create frictions in cross-border trade and investment and hence constitute an impediment to it.
The article goes on to consider contemporary fair trade versus free trade debates, including concerns over trade deficits, currency manipulation, export subsidies, misappropriation of intellectual property rights, and lax labor or environmental standards. The article concludes with a consideration of the case for a larger scope for plurilateral trade agreements internationally, and for a larger scope for active labor market policies domestically to mitigate transition costs from trade.
Martin D. D. Evans and Dagfinn Rime
An overview of research on the microstructure of foreign exchange (FX) markets is presented. We begin by summarizing the institutional features of FX trading and describe how they have evolved since the 1980s. We then explain how these features are represented in microstructure models of FX trading. Next, we describe the links between microstructure and traditional macro exchange-rate models and summarize how these links have been explored in recent empirical research. Finally, we provide a microstructure perspective on two recent areas of interest in exchange-rate economics: the behavior of returns on currency portfolios, and questions of competition and regulation.
James Lake and Pravin Krishna
In recent decades, there has been a dramatic proliferation of preferential trade agreements (PTAs) between countries that, while legal, contradict the non-discrimination principle of the world trade system. This raises various issues, both theoretical and empirical, regarding the evolution of trade policy within the world trade system and the welfare implications for PTA members and non-members. The survey starts with the Kemp-Wan-Ohyama and Panagariya-Krishna analyses in the literature that theoretically show PTAs can always be constructed so that they (weakly) increase the welfare of members and non-members. Considerable attention is then devoted to recent developments on the interaction between PTAs and multilateral trade liberalization, focusing on two key incentives: an “exclusion incentive” of PTA members and a “free riding incentive” of PTA non-members. While the baseline presumption one should have in mind is that these incentives lead PTAs to inhibit the ultimate degree of global trade liberalization, this presumption can be overturned when dynamic considerations are taken into account or when countries can negotiate the degree of multilateral liberalization rather than facing a binary choice over global free trade. Promising areas for pushing this theoretical literature forward include the growing use of quantitative trade models, incorporating rules of origin and global value chains, modeling the issues surrounding “mega-regional” agreements, and modelling the possibility of exit from PTAs. Empirical evidence in the literature is mixed regarding whether PTAs lead to trade diversion or trade creation, whether PTAs have significant adverse effects on non-member terms-of-trade, whether PTAs lead members to lower external tariffs on non-members, and the role of PTAs in facilitating deep integration among members.
Menzie D. Chinn
The idea that prices and exchange rates adjust so as to equalize the common-currency price of identical bundles of goods—purchasing power parity (PPP)—is a topic of central importance in international finance. If PPP holds continuously, then nominal exchange rate changes do not influence trade flows. If PPP does not hold in the short run, but does in the long run, then monetary factors can affect the real exchange rate only temporarily. Substantial evidence has accumulated—with the advent of new statistical tests, alternative data sets, and longer spans of data—that purchasing power parity does not typically hold in the short run. One reason why PPP doesn’t hold in the short run might be due to sticky prices, in combination with other factors, such as trade barriers. The evidence is mixed for the longer run. Variations in the real exchange rate in the longer run can also be driven by shocks to demand, arising from changes in government spending, the terms of trade, as well as wealth and debt stocks. At time horizon of decades, trend movements in the real exchange rate—that is, systematically trending deviations in PPP—could be due to the presence of nontraded goods, combined with real factors such as differentials in productivity growth. The well-known positive association between the price level and income levels—also known as the “Penn Effect”—is consistent with this channel. Whether PPP holds then depends on the time period, the time horizon, and the currencies examined.
Vivian Zhanwei Yue and Bin Wei
This article reviews the literature on sovereign debt, that is, debt issued by a national government. The defining characteristic of sovereign debt is the limited mechanisms for enforcement. Because a sovereign government does not face legal consequences of default, the reasons why it makes repayment are to avoid default penalties related to reputation loss or economic cost. Theoretical and quantitative studies on sovereign debt have investigated the cause and impact of sovereign default and produced analysis of policy relevance. This article reviews the theories that quantitatively account for key empirical facts about sovereign debt. These studies enable researchers and policy makers to better understand sovereign debt crises.
The rise in obesity and other food-related chronic diseases has prompted public-health officials of local communities, national governments, and international institutions to pay attention to the regulation of food supply and consumer behavior. A wide range of policy interventions has been proposed and tested since the early 21st century in various countries. The most prominent are food taxation, health education, nutritional labeling, behavioral interventions at point-of-decision, advertising, and regulations of food quality and trade. While the standard neoclassical approach to consumer rationality provides limited arguments in favor of public regulations, the recent development of behavioral economics research extends the scope of regulation to many marketing practices of the food industry. In addition, behavioral economics provides arguments in favor of taxation, easy-to-use front-of-pack labels, and the use of nudges for altering consumer choices. A selective but careful review of the empirical literature on taxation, labeling, and nudges suggests that a policy mixing these tools may produce some health benefits. More specifically, soft-drink taxation, front-of-pack labeling policies, regulations of marketing practices, and eating nudges based on affect or behavior manipulations are often effective methods for reducing unhealthy eating.
The economic research faces important challenges. First, the lack of a proper control group and exogenous sources of variations in policy variables make evaluation very difficult. Identification is challenging as well, with data covering short time periods over which markets are observed around slowly moving equilibrium. In addition, truly exogenous supply or demand shocks are rare events. Second, structural models of consumer choices cannot provide accurate assessment of the welfare benefits of public policies because they consider perfectly rational agents and often ignore the dynamic aspects of food decisions, especially consumer concerns over health. Being able to obtain better welfare evaluation of policies is a priority. Third, there is a lack of research on the food industry response to public policies. Some studies implement empirical industrial organization models to infer the industry strategic reactions from market data. A fruitful avenue is to extend this approach to analyze other key dimensions of industrial strategies, especially decisions regarding the nutritional quality of food. Finally, the implementation of nutritional policies yields systemic consequences that may be underestimated. They give rise to conflicts between public health and trade objectives and alter the business models of the food sector. This may greatly limit the external validity of ex-ante empirical approaches. Future works may benefit from household-, firm-, and product-level data collected in rapidly developing economies where food markets are characterized by rapid transitions, the supply is often more volatile, and exogenous shocks occur more frequently.