“The Skill Content of Recent Technological Change: An Empirical Exploration”, David H. Autor, Frank Levy, Richard J. Murnane2003-11 (tech economics)⁠:

We apply an understanding of what computers do to study how computerization alters job skill demands. We argue that computer capital (1) substitutes for workers in performing cognitive and manual tasks that can be accomplished by following explicit rules; and (2) complements workers in performing non-routine problem-solving and complex communications tasks.

Provided that these tasks are imperfect substitutes, our model implies measurable changes in the composition of job tasks, which we explore using representative data on task input for 1960^–₃₈1998_26ya. We find that within industries, occupations, and education groups, computerization is associated with reduced labor input of routine manual and routine cognitive tasks and increased labor input of non-routine cognitive tasks.

Translating task shifts into education demand, the model can explain 60% of the estimated relative demand shift favoring college labor during 1970^–₂₈1998_26ya. Task changes within nominally identical occupations account for almost half of this impact.

…To test these predictions, we pair representative data on job task requirements from the Dictionary of Occupational Titles (DOT) [which became O✱NET] with samples of employed workers from the US Census and the Current Population Survey to form a consistent panel of industry and occupational task input over the 4-decade period from 1960^–₃₈1998_26ya. A unique virtue of this database is that it permits us to analyze changes in task input within industries, education groups, and occupations—phenomena that are normally unobservable. By measuring the tasks performed in jobs rather than the educational credentials of workers performing those jobs, we believe our study supplies a missing conceptual and empirical link in the economic literature on technical change and skill demand.

Our analysis provides 4 main pieces of evidence supporting our model:

1. Commencing in the 1970s, labor input of routine cognitive and manual tasks in the U. S. economy declined, and labor input of non-routine analytic and interactive tasks rose.

2. Shifts in labor input favoring non-routine and against routine tasks were concentrated in rapidly computerizing industries. These shifts were small and insignificant in the precomputer decade of the 1960s, and accelerated in each subsequent decade.

3. The substitution away from routine and toward non-routine labor input was not primarily accounted for by educational upgrading; rather, task shifts are pervasive at all educational levels.

4. Paralleling the within-industry task shifts, occupations undergoing rapid computerization reduced input of routine cognitive tasks and increased input of non-routine cognitive tasks.

We consider a number of economic and purely mechanical alternative explanations for our results. Two supply side factors that we study in particular are the rising educational attainment of the workforce and the rising human capital and labor force attachment of women—both of which could potentially generate shifts in job task composition independent of demand shifts. As we show below, the task shifts that we document—and their associations with the adoption of computer technology—are as pervasive within gender, education, and occupation groups as between, indicating that these supply side forces are not the primary explanation for our results.