Specifying Human Capital
回顾了实证增长研究中常用的人力资本度量指标（如识字率、入学率、平均受教育年限），指出这些指标大多不能准确反映人力资本存量。基于人力资本理论，作者扩展了人力资本的设定，允许教育回报递减和不同教育质量，发现不同设定导致各国人力资本存量差异巨大，且错误度量会严重低估人力资本对发展的作用。
A review of the measures of the stock of human capital used in empirical growth research – including adult literacy rates, school enrollment ratios, and average years of schooling of the working‐age population – reveals that human capital is mostly poorly proxied. The simple use of the most common proxy, average years of schooling, misspecifies the relationship between education and the stock of human capital. Based on human capital theory, the specification of human capital is extended to allow for decreasing returns to education and for differences in the quality of a year of education. The different specifications give rise to hugely differing measures of the stock of human capital across countries, and development‐accounting results show that misspecified human capital measures can lead to severe underestimation of the development effect of human capital.