Knowledge that Transforms

Fiscal stimulus payments (i.e., direct lump-sum payments from the government to households) were used in the recessions of 2001 and 2008 in an attempt to simultaneously alleviate households' economic hardship and stimulate aggregate demand. Despite the similarities between the two stimulus policies, there were important differences in both their design and the prevailing economic conditions. We use the model of Kaplan and Violante (2013) to compare the consumption response to these policies. Consistent with empirical evidence from microdata, we find that the consumption response was around one-third lower in 2008, primarily due to the larger size of the payments.

How large are optimal tariffs? What tariffs would prevail in a worldwide trade war? How costly would a breakdown of international trade policy cooperation be? And what is the scope for future multilateral trade negotiations? I address these and other questions using a unified framework which nests traditional, new trade, and political economy motives for protection. I find that optimal tariffs average 62 percent, world trade war tariffs average 63 percent, the government welfare losses from a breakdown of international trade policy cooperation average 2.9 percent, and the possible government welfare gains from future multilateral trade negotiations average 0.5 percent.

I evaluate the empirical premise and the economic logic of the Dodd-Frank Act's requirement that issuers of asset-backed securities retain credit risk.

We explore the impact of reduced transaction costs on risk sharing by estimating the effects of a mobile money innovation on consumption. In our panel sample, adoption of the innovation increased from 43 to 70 percent. We find that, while shocks reduce consumption by 7 percent for nonusers, the consumption of user households is unaffected. The mechanisms underlying these consumption effects are increases in remittances received and the diversity of senders. We report robustness checks supporting these results and use the four-fold expansion of the mobile money agent network as a source of exogenous variation in access to the innovation.

Recent evidence suggests that exposure to a larger share of Limited English (LE) students is associated with a slight decline in performance for students at the top of the achievement distribution. In this paper we explore whether LE peer effects differ by gender and race. Utilizing school-by-year fixed effect methods that allow us to address possible endogeneity with respect to the schools students attend, we find evidence of heterogeneous peer effects of LE students on natives. Specifically, we find no LE student peer effects on females' achievement in math and reading but significant negative effects on males and black students.

We estimate the sensitivity of Internet retail purchasing to sales taxes using eBay data. Our first approach exploits the fact that a seller's location—and therefore the applicable tax rate—is revealed only after a buyer has expressed interest in an item. We document how adverse tax “surprises” reduce the likelihood of purchase and shift subsequent purchases toward out-of-state sellers. We then use more aggregated data to estimate that every one percentage point increase in a state's sales tax increases online purchases by state residents by almost 2 percent, while decreasing their online purchases from state retailers by 3–4 percent.

Motivated by empirical evidence I uncover on the dynamics of French firms' exports, I offer a novel theory of trade frictions. Firms export only into markets where they have a contact. They search directly for new trading partners, but also use their existing network of contacts to search remotely for new partners. I characterize the dynamic formation of an international network of exporters in this model. Structurally, I estimate this model on French data and confirm its predictions regarding the distribution of the number of foreign markets accessed by exporters and the geographic distribution of exports.

We provide novel insights on the decentralization of optimal outcomes under monopolistic competition with nonseparable utility, variable demand elasticity, and endogenous firm heterogeneity. Relative to the unconstrained optimum, equilibrium firm selection is too weak, average firm size is too small, low-cost firms are too small, and high-cost firms are too large. The unconstrained optimum can be decentralized through differentiated production subsidies to producers financed through lump-sum taxes on entrants and consumers. When differentiated subsidies and transfers from entrants are not viable, the constrained optimum can be decentralized through a common production subsidy financed by a lump-sum tax on consumers.

Disparate commitments to reduce GHG emissions create demands for border carbon adjustments (BCAs) to prevent negative competitive effects and carbon leakage. BCAs that accomplish economic objectives and are administratively feasible, WTO-legal, and politically acceptable may be impossible. BCAs should be limited to a few basic energy-intensive and trade-exposed products and should be based on the lower of the carbon content of production in the importing country and actual carbon content, or perhaps “best available technology.” Whether the World Trade Organization (WTO) would condone BCAs is unclear. BCAs violating basic trade rules might qualify for a special exception.

I consider economically sustainable online postsecondary education, including massive open online courses (MOOCs). The analysis suggests that MOOCs will be financially sustainable substitutes for some non-selective postsecondary education, but there are substantial risks. The analysis suggests that MOOCs will be financially sustainable substitutes for only a small share of highly selective postsecondary education (HSPE) and are likely to collapse the economic model that allows HSPE institutions to invest in advanced education and research. I outline a non-MOOC model of online education that may allow HSPE institutions to sustain their distinctive activities and to reach a larger number of students.