The raw bilateral trade data reported by UN Comtrade suffer from two structural problems: reporting differences between country partners and countries reporting in different product classification systems, which require product-level harmonization to compare data across countries. In this paper, we address these challenges by combining a mirroring technique and a data-driven concordance method. Mirroring reconciles importer and exporter differences by estimating country reporting reliability and applying a weighted country-pair average to calculate the estimated trade value. We harmonize product classifications across vintages by calculating conversion weights that reflect a product's market share. The resulting publicly available datasets mitigate issues in raw trade statistics, reducing reporting inconsistencies while maintaining product-level granularity across six decades.

Countries trade more if they liberalized their trade relationship earlier. We derive a gravity equation featuring this path dependence due to sunk market-access costs that generate incumbency effects. We provide supporting evidence for the underlying mechanism and derive an augmented ACR formula (Arkolakis et al., 2012) for the gains from trade that accounts for incumbency effects. A quantification suggests our mechanism explains up to 25% of countries' home shares, and the gains from trade are, on average, 10% larger when allowing for incumbency effects. The analysis further reveals novel distributional effects of trade, boosting real wages but reducing profits.

Estimating trade costs is key to understanding the welfare effects of trade liberalizations. Cost minimization implies that the triangle inequality (TI) of international trade costs must hold for any three countries to avoid cross-border arbitrage. We show that re-routing opportunities might arise when trade costs change because a shipment through an intermediary becomes cheaper. The TI captures such re-routing opportunities. However, standard approaches to calculating the gains from trade liberalizations ignore the TI. We outline an estimation routine that is model-consistent and respects the TI. Counterfactual exercises suggest that the welfare gains from re-routing after trade liberalizations can be substantial.

This paper develops a quantitative general-equilibrium model that endogenously reproduces the fact that most countries trade with only a few partners in narrowly defined industries. Shocks affect trade flows along both the intensive and the extensive margins, as the set of trading partners adjusts endogenously. The framework therefore identifies least-cost substitutes when trade with a key partner country is disrupted. I develop a novel calibration strategy that fits data on industry-level bilateral trade flows and aggregate production. The model endogenously generates pair-specific trade elasticities, and the calibrated version replicates the empirical finding that smaller exporters have larger elasticities. Counterfactual exercises show that accounting for the sparsity of trade flows magnifies welfare changes from trade-cost shocks, especially for lower-income countries, which typically have few active trading partners. For a 10% reduction in global trade barriers, incorporating extensive-margin adjustments increases the average welfare gain by 15% overall and by 30% for the bottom quartile of the income distribution.

We use detailed customs records to document how sanctioned goods continue to reach Russia through third countries. Combining this evidence with a quantitative trade model that features endogenous transshipment, we study how evasion weakens export bans and how sanctions can be made more effective when trade can be rerouted.

We study how globalization changes who works with whom by creating incentives for forming highly productive teams. Combining evidence from inventor teams with a quantitative trade model, we quantify how the resulting concentration of talent affects inequality and the gains from trade.

We use detailed Swiss administrative data to look inside a major tax haven and study how multinationals respond to changing tax incentives. Focusing on US multinationals and the 2017 US tax reform (Tax Cuts and Jobs Act), we document the effects on the profits they book, their real economic activity, and local labor markets.

International trade research relies heavily on data reported at the product level. Regular classification updates of the “Harmonized System” lead to intertemporal inconsistencies affecting up to 44% of world goods trade. Existing methods to standardize product vintages either drop numerous products over time or bulk updated codes into large synthetic categories. We largely overcome these issues by developing an algorithm that exploits the persistence of trade data to convert trade flows between vintages. Our conversion estimates are robust to year and sample choices. Provided a clear correspondence and persistent data, the algorithm can be applied to other classifications.