Structural Change and Global Trade
Services, which are less traded than goods, rose from 50 percent of world expenditure in 1970 to 80 percent in 2015. Such structural change restrained "openness"--the ratio of world trade to world GDP--over this period. We quantify this with a general equilibrium trade model featuring non-homothetic preferences and input-output linkages. Openness would have been 70 percent in 2015, 23 percentage points higher than the data, if expenditure patterns were unchanged from 1970. Structural change is critical for estimating the dynamics of trade barriers and welfare gains from trade. Ongoing structural change implies declining openness, even absent rising protectionism.