Academic Report of School of Mathematical Sciences [2026] No. 086

(Series Report for High-Level University Construction No. 1345)

Title：Semiparametric Maximum Likelihood Estimation in Cox Model with a Change Point for “Case 1” Data

Speaker：Professor Tong Xingwei(Beijing Normal University)

Time：15:50-16:40, Sept. 12, 2026

Location：Room 601, Huiyan Building, Yuehai Campus

Abstract: This study proposes a new method for estimating the change point parameter in a Cox proportional hazards model for “case 1” interval-censored data. We establish the semiparametric maximum likelihood estimation with its computational scheme and propose a hypothesis test for testing the null hypothesis of no change point. The proposed method provides consistency, asymptotic independence and semiparametric efficiency properties under certain assumptions. Numerical performance is demonstrated by simulation studies, showing that the proposed methodology achieves high accuracy and accurate coverage probability.

Using an HIV clinical dataset collected via AIDS Clinical Trials Group Protocol 175 (ACTG175), the methodology is applied to demonstrate that HIV patients older than 46 years may benefit less from the new therapy compared with the young.

Speaker Profile：Tong Xingwei is a professor and doctoral advisor at Beijing Normal University. He currently serves as Chair of the Department of Mathematical and Statistical Sciences at Beijing Normal University and Director of the Guangdong Provincial Key Laboratory of Educational Psychology and Data Science Technology and Applications. He earned his Ph.D. from the School of Mathematical Sciences at Peking University and completed a postdoctoral fellowship at the University of Missouri, Columbia. He has long been engaged in cutting-edge research in the fields of biostatistics, financial statistics, causal analysis, and robust statistics. He currently serves as an Executive Council Member of the Chinese Causal Inference Branch; Vice President of the Chinese Association for the Teaching of Industrial Statistics; Executive Council Member of the Chinese Chapter of the International Society for Biostatistics; and Vice President of the Beijing Big Data Association, among other positions. He has led one key research and development project funded by the Ministry of Science and Technology, one key sub-project under the National Natural Science Foundation of China, and multiple general projects funded by the National Natural Science Foundation of China. He has published more than 50 academic papers in journals such as Annals of Statistics, Biometrika, and Statistica Sinica.

Faculty and students are welcome to attend!

Invited by: Zhou Yan

School of Mathematical Sciences

September 9, 2026