On May 13, 2019, the Institute of Science, Technology and Society invited Dr. You Tianlong of Arizona State University to give a lecture at CASTED. Dr. You introduced the history of international migration in the past 100 years, and analyzed the different flow patterns of high-skilled migrants and low-skilled migrants from the perspective of economics and sociology. A large volume of earlier studies show that the cross-border movement of high-skilled migrants makes a positive impact on the recipient countries, and will not lead to the hollowing-out of research institutions in the exporting countries. Low-skilled migrants can fill the labor shortage of low-end industries in the recipient countries, thus making a positive impact on their economic development; but in the long run, it is not conducive to the economic restructuring of the exporting countries and may cause social problems. Dr. You also introduced the current systems and policies related to international migration. Researchers from the Institute of Science, Technology and Society, the Institute of S&T Systems and Management, the Institute of S&T for Industrial Development and the Institute of Comprehensive Management and some experts from outside the Institute participated in the lecture, and had an in-depth discussion with Dr. You.