The authors estimate the domestic value-added content in exports of manufacturing goods (VAX-D ratio) for 91 countries over the period from 1970 to 2013. They find a strong decline in the world VAX-D ratio since the mid-1980s mostly accounted for by the substitution of foreign for domestic intermediates. Using a breakpoint detection method, they identify three waves of vertical specialisation in the world economy: 1970–1979, 1986–1995 and 1996–2008. The authors find that most countries (79) initiated a period of vertical specialisation at least once. They find strong evidence that the VAX-D ratio correlates negatively with GDP per capita, and that the negative slope is flattening out at higher levels of income.

中文翻译：

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纵向贸易专业化模式：91个国家的长期证据

作者估计1970年至2013年期间91个国家的制造业产品出口的国内增值含量（VAX-D比率）。他们发现，自1980年代中期以来，世界VAX-D比率出现了大幅下降通过将外国替代为国内中间体。他们使用断点检测方法确定了世界经济中的三个垂直专业化浪潮：1970–1979、1986–1995和1996–2008。作者发现，大多数国家（79个）至少启动了一次垂直专业化时期。他们发现有力的证据表明，VAX-D比率与人均GDP呈负相关，并且负斜率在较高的收入水平上正在趋于平缓。