The Changing Skill Requirements of Jobs in the U.S. Economy
研究了1960至1976年间美国经济中工作技能分布的变化，发现就业分布向高技能工作倾斜，但单个职业的技能要求变化缩小了技能分布差距，整体平均技能要求上升但增速放缓。
Changes in the aggregate distribution of job skills result from changes in the distribution of employment among occupations as well as from changes in the skill requirements of individual occupations. This study measures the effects of both of these factors on the distribution of skills in the U.S. economy between 1960 and 1976. Skill changes in individual occupations are measured with data from the two most recent editions of the Dictionary of Occupational Titles on the general skill requirements of all individual jobs. The analysis reveals that between 1960 and 1976 changes in the distribution of employment have favored more skilled jobs, while changes in the skill requirements of individual occupations have tended to narrow the distribution of job skills. Overall the average skill requirements of jobs increased in this period, but at a slower rate than in earlier periods.