We study inference in shift-share regression designs, such as when a regional outcome is regressed on a weighted average of sectoral shocks, using regional sector shares as weights. We conduct a placebo exercise in which we estimate the effect of a shift-share regressor constructed with randomly generated sectoral shocks on actual labor market outcomes across U.S. commuting zones. Tests based on commonly used standard errors with 5% nominal significance level reject the null of no effect in up to 55% of the placebo samples. We use a stylized economic model to show that this overrejection problem arises because regression residuals are correlated across regions with similar sectoral shares, independent of their geographic location. We derive novel inference methods that are valid under arbitrary cross-regional correlation in the regression residuals. We show using popular applications of shift-share designs that our methods may lead to substantially wider confidence intervals in practice.

Much of the variation in international trade volume is driven by firms’ extensive margin decisions of whether to participate in export markets. We evaluate how the information potential exporters possess influences their decisions. We estimate a model of export participation in which firms weigh the fixed costs of exporting against the forecasted profits from serving a foreign market. We adopt a moment inequality approach, placing weak assumptions on firms’ expectations. The framework allows us to test whether firms differ in the information they have about foreign markets. We find that larger firms possess better knowledge of market conditions in foreign countries, even when those firms have not exported in the past. Quantifying the value of information, we show that, in a typical destination, total exports rise while the number of exporters falls when firms have access to better information to forecast export revenues.

How global are the gains from innovation? When firms operate plants in multiple countries, technological improvements developed in one location may be shared with foreign sites for efficiency gain. We develop a model that accounts for such transfer and apply it to measure returns to R&D investment for a panel of US multinationals. Our estimates indicate that innovation increases performance at firm locations beyond the innovating site: the median multinational firm realizes abroad 20% of the return to its US R&D investment, revealing a spatial disconnect between the costs and potential gains of policies that encourage multinationals’ US innovation.

We study state taxes as a potential source of spatial misallocation in the U.S.. We build a spatial general equilibrium framework that incorporates salient features of the U.S. state tax system, and use changes in state tax rates between 1980 and 2010 to estimate the model parameters that determine how worker and firm location respond to changes in state taxes. We find that heterogeneity in state tax rates leads to aggregate welfare losses. In terms of consumption equivalent units, harmonizing state taxes increases worker welfare by 0.6% if government spending is held constant, and by 1.2% if government spending responds endogenously. Harmonization of state taxes within Census regions achieves most of these gains. We also use our model to study the general equilibrium effects of recently implemented and proposed tax reforms.

Exporting firms often enter foreign markets that are similar to their previous export destinations. We develop a dynamic model in which a firm’s exports in a market may depend on how similar the market is to the firm’s home country (gravity) and to its previous export destinations (extended gravity). Given the large number of export paths from which forward-looking firms may choose, we use a moment inequality approach to estimate our model. Our estimates indicate that sharing similarities with a prior export destination in terms of geographic location, language, and income per capita jointly reduces the cost of foreign market entry by 69–90%. Reductions due to geographic location (25–38%) and language (29–36%) have the largest effect. Extended gravity thus has a large impact on export entry costs.

We study the relationship between domestic-demand shocks and exports using data for Spanish manufacturing firms in 2002–2013. Exploiting plausibly exogenous geographical variation caused by the Great Recession, we find that firms whose domestic sales declined by more experienced a larger increase in export flows, controlling for firms’ supply determinants. This result illustrates the capacity of export markets to counteract the negative impact of local demand shocks. By structurally estimating a heterogeneous-firm model of exporting with nonconstant marginal costs of production, we conclude that these firm-level responses accounted for half of the spectacular increase in Spanish goods exports over the period 2009–2013.

We provide measures of ethnic and racial segregation in urban consumption. Using Yelp reviews, we estimate how spatial and social frictions influence restaurant visits within New York City. Transit time plays a first-order role in consumption choices, so consumption segregation partly reflects residential segregation. Social frictions also affect restaurant choices: individuals are less likely to visit venues in neighborhoods demographically different from their own. While spatial and social frictions jointly produce significant levels of consumption segregation, we find that restaurant consumption is only about half as segregated as residences. Consumption segregation owes more to social than spatial frictions.