(MIT: Cambridge, Massachusetts) -- When you use self-checkout machines in supermarkets and drugstores, you’re probably not doing a better job of bagging your purchases than checkout clerks once did. Automation just makes bagging less expensive for large retail chains.

“If you introduce self-checkout kiosks, it’s not going to change productivity all that much,” says MIT economist Daron Acemoglu. However, in terms of lost wages for employees, he adds, “It’s going to have fairly large distributional effects, especially for low-skill service workers. It’s a labor-shifting device, rather than a productivity-increasing device.”

A newly published study co-authored by Acemoglu quantifies the extent to which automation has contributed to income inequality in the U.S., simply by replacing workers with technology—whether self-checkout machines, call-center systems, assembly-line technology, or other devices. During the last four decades, the income gap between more- and less-educated workers has grown significantly; the study finds that automation accounts for more than half of that increase.

“This single variable... explains 50 to 70 percent of the changes or variation between group inequality from 1980 to about 2016,” Acemoglu says.

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