We present a framework for understanding the effects of automation and other types of technological changes on labor demand, and use it to interpret changes in US employment over the recent past. At the center of our framework is the allocation of tasks to capital and labor—the task content of production. Automation, which enables capital to replace labor in tasks it was previously engaged in, shifts the task content of production against labor because of a displacement effect. As a result, automation always reduces the labor share in value added and may reduce labor demand even as it raises productivity. The effects of automation are counterbalanced by the creation of new tasks in which labor has a comparative advantage. The introduction of new tasks changes the task content of production in favor of labor because of a reinstatement effect, and always raises the labor share and labor demand. We show how the role of changes in the task content of production—due to automation and new tasks—can be inferred from industry-level data. Our empirical decomposition suggests that the slower growth of employment over the last three decades is accounted for by an acceleration in the displacement effect, especially in manufacturing, a weaker reinstatement effect, and slower growth of productivity than in previous decades.

中文翻译：

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自动化和新任务：技术如何替代和恢复劳动力

我们提供了一个框架，用于理解自动化和其他类型的技术变化对劳动力需求的影响，并用它来解释最近一段时间美国就业的变化。我们框架的中心是将任务分配给资本和劳动力，即生产的任务内容。自动化使资本能够替代以前从事的任务中的劳动力，由于转移效应，使生产的任务内容相对于劳动力发生了变化。结果，自动化总是会减少增加值中的劳动力份额，即使提高生产率也可能减少劳动力需求。通过创建新的任务来抵消自动化的影响，在这些新任务中，劳动力具有相对优势。新任务的引入由于恢复作用而改变了生产的任务内容而有利于劳动，并总是提高劳动份额和劳动力需求。我们展示了如何根据行业数据来推断由于自动化和新任务而导致的生产任务内容变化的作用。我们的经验分解表明，过去三十年来，就业增长的放缓是由取代效应（尤其是制造业）加速增长，恢复效应减弱以及生产率增长较前几十年放缓造成的。