Hidden Exposure: Measuring US Supply Chain Reliance
利用全球投入产出数据，发现美国对国外供应商（尤其是中国）的暴露程度远大于传统贸易数据所示，但宏观层面80%以上工业投入来自国内，暴露相对有限；近期冲击多为系统性，政策应聚焦具体产品而非整个制造业。
ABSTRACT: Supply chain problems, previously relegated to specialized journals, now appear in G7 Leaders' Communiqués. Our paper looks at three core elements of the problems: measurement of the links that expose supply chains to disruptions, the nature of the shocks that cause the disruptions, and the criteria for policy to mitigate the impact of disruptions. Utilizing global input-output data, we show that the US exposure to foreign suppliers, and particularly to China, is "hidden" in the sense that it is much larger than what conventional trade data suggest. However, at the macro level, exposure remains relatively modest, given that over 80 percent of US industrial inputs are sourced domestically. We argue that many recent shocks to supply chains have been systemic rather than idiosyncratic. Moreover, systemic shocks are likely to arise from climate change, geoeconomic tensions, and digital disruptions. Our principal conclusion is that the concerns regarding supply chain disruptions, and policies to address them, should focus on individual products rather than the whole manufacturing sector.