Deciphering Prometheus: Temporal Change in the Skill Level of Work
梳理了关于工作技能水平随时间变化的三种主要假说（升级、降级、无净变化），指出研究结论分歧的原因在于研究设计差异，并提出未来应更系统评估构成与工作内容变化、完善时空采样及技能测量方法。
Major hypotheses about temporal change in the skill levels of work correspond to notions of upgrading, downgrading, and little net change. This paper identifies reasons why research has been equivocal on the larger question. Research designs yield differing conclusions: aggregate studies suggest little net change in recent years; case studies portray more volatile upgrading and downgrading within subsectors. A comprehensive answer to the question of skill transformation will require more systematic assessment of compositional and work content shifts, more complete sampling of the temporal and spatial domain, and better concepts and measures for skill. An improved approach includes direct measurement of two primary dimensions of skill, substantive complexity and autonomy-control. A review of existing aggregate studies illustrates the methodological problems and suggests future directions and hypotheses.