After earning his PhD in Economics at Keio University in 2015, Shin'ichi Yamaguchi joined the International University of Japan (国際大学) as an associate professor at the Center for Global Communications. He also serves as the director of the Risk Communication Institute (日本リスクコミュニケーション協会) and an advisor of numerous organizations including SIEMPLE Inc., Japan Agency for Marine-Earth Science and Technology (国立研究開発法人海洋研究開発機構), and GREE Inc.

A specialist in statistics and econometrics, Yamaguchi is known for his study on social media platforms. According to him, extremists tend to write their opinions more frequently, and the moderate majority keeps quiet because they are afraid of attacks from the extremists on online platforms (2018 essays; September, December).