The Direction of Technical Change and Economic Growth

人们普遍认为技术进步是经济增长的引擎。尽管有大量文献研究技术进步的决定因素，但关于哪些因素形成了开发不同类型技术的激励因素的研究相对较少。例如，经济学家的普遍共识是，在过去的两个世纪里，技术变革一直是劳动力增长型的，从某种意义上说，它提高了劳动力的生产率，而不是资本的生产率。同样，至少在过去的50年里，技术变革似乎对技能有偏见，从某种意义上说，技术和受过教育的工人比没有技术和受教育程度较低的工人受益更多。尽管有这些公认的模式，但我们对技术发展采取这些特殊形式的原因知之甚少。这个项目调查了企业和社会开发和实施不同类型技术的动机。它表明，技术所支配的市场规模和相对要素价格决定了这些激励措施：人们将更多地致力于开发能够节省更昂贵的要素并占据更大市场规模的技术。它展示了这些因素如何解释我们在数据中观察到的广泛模式。该项目对这类技术变革对跨国收入差异的影响。例如，以技能为导向的技术变革将扩大拥有丰富技术工人的富国与缺乏技术工人的穷国之间的收入差距。同样，取决于资本和劳动密集型产品的可替代性，劳动密集型技术变革也可能扩大这一差距。该项目还研究了劳动力稀缺性的差异如何影响经济增长率，并解释了为什么劳动力稀缺性更严重的国家可能是19世纪最早实现工业化的国家。

There is widespread agreement that technical progress is the engine of economic growth. Despite a large literature investigating determinants of technical progress, there is relatively little work on what factors shape the incentives to develop different types of technologies. For example, the general consensus among economists is that technical change throughout the past two centuries has been labor-augmenting, in the sense that it increased the productivity of labor more than that of capital. Similarly, technical change appears to have been skill-biased at least for the past 50 years, in the sense that it has benefited skilled and educated workers more than unskilled and less educated workers. Despite these well-established patterns, we know little about the reasons why technological developments have taken these particular forms. This project investigates the incentives for firms and the society to develop and implement different types of technologies. It demonstrates that the size of the markets that technologies command and relative factor prices shape these incentives: there will be more effort devoted to develop technologies that save on more expensive factors and command a greater market size. It shows how these factors explain the broad patterns we observe in the data.The project draws implications for this type of technical change for cross-country income differences. For example, skill-biased technical change will increase the income gap between rich countries that are abundant in skilled workers and poor countries that are scarce in skilled workers. Similarly, depending on how substitutable capital and labor-intensive products are, labor-augmenting technical change may also increase this gap. The project also investigates how differences in the scarcity of labor may affect the growth rate of the economy, and offers an explanation for why countries with greater labor scarcity may have been the first ones to industrialize during the 19th century.