Engineering Growth
首次系统考察工程师在第二次工业革命期间的作用，发现美国县级工程师密度与当今收入显著相关，可解释10%的收入差异，而美洲国家间工程师密度差异可解释约四分之一的收入分化。
Abstract This paper offers the first systematic historical evidence on the role of a central actor in modern growth theory: the engineer. We construct a database on the share of engineers in the labor force during the Second Industrial Revolution (1870–1914) at the county level for the United States and the state and national levels for the Americas. These measures are robustly correlated with income today after controlling for literacy, other types of higher-order human capital (college graduates, lawyers, physicians, patenting) and demand-side factors, as well as after instrumenting engineering using the 1862 US Land Grant Colleges program. Differences in engineering density in 1880 accounted for 10% of the higher US county incomes today, while national disparities in engineering density can explain approximately a quarter of the income divergence in the Americas. To document the mechanisms through which engineering density works, we show how it is correlated with higher rates of technology adoption and structural transformation across intermediate time periods and with numerous measures of the knowledge economy today.