Four Facts about Human Capital
总结了自Becker（1962）以来经济学家对人力资本的四个典型事实，涵盖人力资本对收入差异的解释力、投资回报、基础技能培养和高级技能价值，适合关注人力资本与经济发展的学者快速了解核心发现。
This paper synthesizes what economists have learned about human capital since Becker (1962) into four stylized facts. First, human capital explains at least one-third of the variation in labor earnings within countries and at least half of the variation across countries. Second, human capital investments have high economic returns throughout childhood and young adulthood. Third, we know how to build foundational skills such as literacy and numeracy, and resources are often the main constraint. Fourth, higher-order skills such as problem-solving and teamwork are increasingly valuable, and the technology for producing these skills is not well understood. We know that investment in education works and that skills matter for earnings, but we do not always know why.