On June 29, 2022, the latest research achievement "Social Networks with Unobserved Links" by Associate Professor Qu Xi of ACEM, Professor Arthur Lewbel of Boston College and Professor Xun Tang of Rice University was officially accepted and published by the Journal of Political Economy, one of the world's top economic journals.

In this paper, Associate Professor Qu Xi and her collaborators studied how to identify and estimate linear social network when it is difficult to observe network links. The required data consist of many small networks in a certain period, such as classrooms or villages, and panel data or multi-period cross-sectional data are not needed. Using the data of Tennessee's Project STAR (Students-Teacher Achievement Ratio) for empirical analysis, this paper identifies and estimates the impact of peer effect and context effect on students' math scores without observing the potential network of each classroom. The paper has found that the peer effect of class size of about 22 people is greater than that of about 15 people, and the peer effect will indeed affect students' math scores. This social network model proposed by Associate Professor Qu Xi and her collaborators can be used to analyze the connections between economic individuals, and is of great significance to the study of peer effect and individual behaviors.

Qu Xi, associate professor of Antai College of Economics and Management (ACEM), graduated with PhD degree from the Department of Economics of Ohio State University in 2013, before which she received a bachelor's degree from the School of Economics of Peking University in 2006, and a master's degree from Guanghua School of Management of Peking University in 2008. Her research fields are econometric theory and regional economy, especially focusing on spatial econometric models and their applications in spatial spillover and peer effects. Before this paper published in JPE, she has published several papers in Journal of Econometrics, Quantitative Economics, Econometric Theory, Journal of Business & Economic Statistics, Regional Science and Urban Economics and Labor Economics, which have been widely cited. 

Journal of Political Economy is a world-class economic journal, ranking among the world's top five all the year round. Founded in 1892, it is an international core journal in the field of economics, published by the University of Chicago Press, bimonthly. Its content covers all major economic fields, including microeconomic theory, macroeconomic theory, monetary theory, fiscal policy, labor economics, development economics, international trade and finance, industrial organization and social economics. More than 5000 (5334) papers since 1899 can be retrieved on WOS, of which the journal impact factor in 2021 is 9.637 and the five-year impact factor is 11.087.