The article estimates how easily machines and people can replace each other in different industries in the U.S. They looked at data from 1960 to 2005 for 35 industries. They found that overall, it's easier to swap machines for people than the other way around. Most industries also find it easier to use machines instead of people. The change in technology seems to make it easier to use people more efficiently. Manufacturing industries find it harder to switch between machines and people compared to service industries. Industries that make things for people to use find it harder to switch between machines and people compared to industries that make things for people to buy.