"Every five years, the World Congress of the Econometric Society brings together scholars from around the world. Leading scholars present state-of-the-art overviews of their areas of research, offering newcomers access to key research in economics. Advances in Economics and Econometrics: Twelfth World Congress consist of papers and commentaries presented at the Twelfth World Congress of the Econometric Society. This two-volume set includes surveys and interpretations of key developments in economics and econometrics, and discussion of future directions for a variety of topics, covering both theory and application. The first volume addresses such topics as contract theory, industrial organization, health and human capital, as well as racial justice, while the second volume includes theoretical and applied papers on climate change, time series econometrics, and causal inference. These papers are invaluable for experienced economists seeking to broaden their knowledge or young economists new to the field"-- Provided by publisher.

We present a theory of Keynesian supply shocks: supply shocks that trigger changes in aggregate demand larger than the shocks themselves. We argue that the economic shocks associated to the COVID-19 epidemic--shutdowns, layoffs, and firm exits--may have this feature. In one-sector economies supply shocks are never Keynesian. We show that this is a general result that extend to economies with incomplete markets and liquidity constrained consumers. In economies with multiple sectors Keynesian supply shocks are possible, under some conditions. A 50% shock that hits all sectors is not the same as a 100% shock that hits half the economy. Incomplete markets make the conditions for Keynesian supply shocks more likely to be met. Firm exit and job destruction can amplify the initial effect, aggravating the recession. We discuss the effects of various policies. Standard fiscal stimulus can be less effective than usual because the fact that some sectors are shut down mutes the Keynesian multiplier feedback. Monetary policy, as long as it is unimpeded by the zero lower bound, can have magnified effects, by preventing firm exits. Turning to optimal policy, closing down contact-intensive sectors and providing full insurance payments to affected workers can achieve the first-best allocation, despite the lower per-dollar potency of fiscal policy.

This paper argues that adding endogenous information aggregation to situations where coordination is important - such as riots, self-fulfilling currency crises, bank runs, debt crises or financial crashes - yields novel insights into the multiplicity of equilibria. Morris and Shin (1998) have highlighted the importance of the information structure for this question. They also show that, with exogenous information, multiplicity collapses when individuals observe fundamentals with small enough idiosyncratic noise. In the spirit of Grossman and Stiglitz (1976), we endogenize public information by allowing individuals to observe financial prices or other noisy indicators of aggregate activity. In equilibrium these indicators imperfectly aggregate disperse private information without ever inducing common knowledge. Importantly, their informativeness increases with the precision of private information. We show that multiplicity may survive and characterize the conditions under which it obtains. Interestingly, endogenous information typically reverses the limit result: multiplicity is ensured when individuals observe fundamentals with small enough idiosyncratic noise. Keywords: Multiple equilibria, coordination, self-fulfilling expectations, speculative attacks, currency crises, bank runs, financial crashes, rational-expectations, global games. JEL Classifications: D8, E5, F3, G1.

To what degree should societies allow inequality to be inherited? What role should estate taxation play in shaping the intergenerational transmission of welfare? We explore these questions by modeling altruistically-linked individuals who experience privately observed taste or productivity shocks. Our positive economy is identical to models with infinite-lived individuals where efficiency requires immiseration: inequality grows without bound and everyone's consumption converges to zero. However, under an intergenerational interpretation, previous work only characterizes a particular set of Pareto-efficient allocations: those that value only the initial generation's welfare. We study other efficient allocations where the social welfare criterion values future generations directly, placing a positive weight on their welfare so that the effective social discount rate is lower than the private one. For any such difference in social and private discounting we find that consumption exhibits mean-reversion and that a steady-state, cross-sectional distribution for consumption and welfare exists, where no one is trapped at misery. The optimal allocation can then be implemented by a combination of income and estate taxation. We find that the optimal estate tax is progressive: fortunate parents face higher average marginal tax rates on their bequests. Keywords: Inequality, Altruism, Private Information, Immiseration, Social Discounting, Optimal Taxation, Estate Taxes, Dynamic Programming. JEL Classifications: C61, C62, D30, D63, D64, D82, H21, H23, H24, H43.

This paper develops a simple theory of capital controls as dynamic terms-of-trade manipulation. We study an infinite horizon endowment economy with two countries. One country chooses taxes on international capital flows in order to maximize the welfare of its representative agent, while the other country is passive. We show that capital controls are not guided by the absolute desire to alter the intertemporal price of the goods produced in any given period, but rather by the relative strength of this desire between two consecutive periods. Specifically, it is optimal for the strategic country to tax capital inflows (or subsidize capital outflows) if it grows faster than the rest of the world and to tax capital outflows (or subsidize capital inflows) if it grows more slowly. In the long-run, if relative endowments converge to a steady state, taxes on international capital flows converge to zero. Although our theory emphasizes interest rate manipulation, the country's net financial position per se is irrelevant -- National Bureau of Economic Research web site.

The theory of comparative advantage is at the core of neoclassical trade theory. Yet we know little about its implications for how nations should conduct their trade policy. For example, should import sectors with weaker comparative advantage be protected more? Conversely, should export sectors with stronger comparative advantage be subsidized less? In this paper we take a first stab at exploring these issues. Our main results imply that in the context of a canonical Ricardian model, optimal import tariffs should be uniform, whereas optimal export subsidies should be weakly decreasing with respect to comparative advantage, reflecting the fact that countries have more room to manipulate prices in their comparative-advantage sectors. Quantitative exercises suggest substantial gains from such policies relative to simpler tax schedules.