Average most-favored-nation tariffs in the "Quad" (Canada, the European Union, Japan, and the United States) have fallen to about 5 percent. But tariffs more than three times the average most-favored-nation duty are not uncommon in the Quad and have a disproportionate effect on exports of least...

A developing country's good (or bad) export performance in one market can affect its future export performance not only in the same market but also in "neighboring" markets. This happens if importers in different countries share information about a particular exporter's performance or if...