Using national level data on worldwide robot shipments across 17 countries, George Graetz and Guy Michaels show that robots may have been responsible for about a tenth of the increases in those countries’ gross domestic product between 1993 and 2007, and may have increased labor productivity growth by over 15%. This might sound like it’s a small number, but it’s not. According to the authors, this number is comparable to the impact of steam engines on British labor productivity growth in the 19^th Century. Does this growth come at the expense of labor? Graetz and Michaels find some evidence that wages go up on average as robot use increases. But they also find some evidence that hours worked drops for low-skilled and middle-skilled workers. A paper by Daron Acemoglu and Pascual Restrepo focuses on the effect of robots on the U.S. labor market and estimates that each additional robot reduces employment by seven workers and that one new robot per thousand workers reduces wages by 1.2 to 1.6%.