Does technology replace more jobs than it creates? What is the net balance between these two things? Until now, that has not been measured. But a new research project led by MIT economist David Autor has developed an answer, at least for U.S. history since 1940.The study uses new methods to examine how many jobs have been lost to machine     1    , and how many have been generated through “augmentation(增强),” in which technology creates new tasks. Overall, the study finds, and particularly since 1980, technology has replaced more U.S. jobs than it has     2    .

“There does appear to be a faster rate of automation, and a slower rate of augmentation, in the last four decades, from 1980 to the present, than in the four decades     3    ,” says Autor.However, that finding is only one of the study’s     4    .The researchers have also developed an entirely new method for studying the issue, based on an analysis of thousands of U.S.censusjob categories in relation to a(n)     5     look at the text of U.S. patents over the last century. That has allowed them, for the first time, toquantifythe effects of technology over both job loss and job creation.

The study finds that overall, about 60 percent of jobs in the U.S. represent new types of work, which have been created since 1940.To determine this, Autor and his colleagues     6     through about 35,000 job categories, tracking how they emerge over time. They also used natural language processing tools to analyze the text of every U.S. patent filed since 1920. That allowed them to     7     links between new technologies and their effects on employment.

From about 1940 through 1980, for instance, jobs like elevator operator and typesetter(排字工人) tended to get automated. But at the same time, more workers —    8     roles such as shipping and receiving clerks, buyers and department heads, and civil and space engineers.  From 1980 through 2018, the ranks of cabinetmakers and machinists, among others, have been     9     by automation, while industrial engineers, and operations and systems researchers and analysts, have enjoyed growth.

Ultimately, the research suggests that the negative effects of automation on employment were more than twice as great in the 1980-2018 period as in the 1940-1980 period.There was a more     10    , and positive, change in the effect of augmentation on employment in 1980-2018, as compared to 1940-1980.