George C. Tiao, 1933–2026

George C. Tiao, Allen Wallis Emeritus Professor of Econometrics and Statistics at the University of Chicago, Booth School of Business, passed away on 25 April 2026 at the age of 92. With his passing, the statistical profession has lost a rare and outstanding leader in Bayesian inference, time series analysis and environmental statistics. Also, more widely, the business statistics community and Chinese statisticians around the world have lost one of their most devoted and visionary figures; a path-finding beacon they looked up to. George was born on 8 November 1933 in London, United Kingdom, and was raised in China during one of its most turbulent periods. His family moved to Taiwan in 1950 and George earned his Bachelor’s degree in Economics from the National Taiwan University in 1955. He moved to the United States in 1956, earned his MBA from Stern School of Business, New York University in 1958 and his PhD from University of Wisconsin, Madison in 1962 under the supervision of George E.P. Box and Arthur Goldberger. He remained at the Department of Statistics at Wisconsin for the next 20 years, serving as Chairman from 1973 to 1975 and became Bascom Professor of Statistics in 1981. He moved to Chicago Booth in 1982, serving as Allen Wallis Professor of Econometrics and Statistics until his retirement in 2003. Among his many honours, he received the Julius Shiskin Award in 2001, Wilks Memorial Medal also in 2001, Distinguished Service Medal of the Directorate General of Budget, Accounting and Statistics in Taiwan in 1993, and Statistician of the Year for the Chicago Chapter of the American Statistical Association in 2005. He received Honorary Doctorates in 2003 from the Universidad Carlos III de Madrid, Spain and the National Tsinghua University, Hsinchu, Taiwan. He was elected a fellow of the American Statistical Association, Institute of Mathematical Statistics, and the Royal Statistical Society, and member of the International Institute of Statistics. He was elected as an Academician at Academia Sinica, Taiwan in 1976. He was also an honorary professor of many universities in China and Taiwan, including Peking University. George was the founding chair editor of Statistica Sinica and the founding president of the International Chinese Statistical Association. He was one of the key organizers of the annual NBER/NSF Time Series Conference for over 25 years and established the annual conference of Making Statistics More Effective in Business Schools in 1986. He played an instrumental role in statistical education in Taiwan and China, founding the Institute of Statistical Sciences in Academia Sinica, Taiwan, the Department of Business Statistics and Econometrics at Guanghua School of Management at Peking University, and the College of Technology Management, National Tsinghua University, Taiwan. He supervised more than 25 PhD students and served as advisor to the central banks of several countries and to the US Census Bureau. With boundless enthusiasm, careful attention to substantive problems at hand, and use of theoretically sound, yet simple, methodology for data analysis, George made many fundamental and significant research contributions to the profession. He published more than 150 articles in leading environmental and statistical journals and several books. He was an international leader in Bayesian statistics, providing groundwork for random-effect models, Bayesian robustness, outlier detection, and a data-translated likelihood approach for constructing noninformative priors. His book Bayesian Inference in Statistical Analysis, published jointly with George E.P. Box is recognized as a classic. George was synonymous with time series analysis. His many important contributions in this area included proposing the intervention analysis with George E.P. Box, developing systematic procedures for outlier detection and analysis, including random variance changes and random level shift, and new methods for identifying stationary and nonstationary ARMA models. His work generated a deeper understanding of seasonal adjustment and ground-breaking methodology for model-based seasonal adjustment, methods for identifying co-integration in multivariate time series, and use of macro-economic and time series models in macro-economic forecasting. He developed new approaches for understanding the identifiability of vector ARMA models and temporal aggregation and complex unit roots in univariate time series. George was a leader and pioneer in using statistical methods for ozone study. He was a key member of the Ozone Science Tiger Team that won the 2005 Environmental Protection Agency award and was one of the first scientists who used statistical methods to detect a significant decrease in the stratospheric ozone level. The George C. Tiao Reading Room at the Peking University was officially inaugurated in 2011. In December 2013, the Institute of Statistical Science, Academia Sinica held an academic symposium in celebration of his 80th birthday, allowing many distinguished scholars at home and abroad to pay tribute to him. ‘A conversation with George C. Tiao’, published in Statistical Science in 2010, gives further detailed insights into George’s life, career, and personality. George was a caring family man who enjoyed gourmet food, music, and opera. He married Barbara in 1958 and they had four children. She died in March 2008. George is survived by his daughters Vivian and Julie, his sons Gregory and Paul, and nine grandchildren.