Arthur Pentland Dempster, longtime Harvard statistics professor who developed the EM algorithm and Dempster-Shafer theory of belief functions, died on January 30, 2026, at age 96, leaving a lasting mark on statistical inference and fields from machine learning to artificial intelligence.
Obituaries
Obituary: George C. Tiao
George C. Tiao, a giant of modern statistics and beloved leader of the international statistical community, passed away peacefully in his sleep in Chicago on April 25, 2026, at the age of 92.
Obituary: Gudmund Ragnvaldsson Iversen
Gudmund Ragnvaldsson Iversen, a well-loved husband, father, grandfather, and professor emeritus at Swarthmore College, passed away peacefully on May 2 in Springfield, Pennsylvania.
Obituary: William S. Cleveland
William S. Cleveland, Shanti S. Gupta Distinguished Professor of Statistics and courtesy professor of computer science at Purdue University, passed away on March 27, 2026, at the age of 83.
Obituary: Arak M. Mathai
Arak M. Mathai—an eminent mathematician and statistician whose work shaped modern multivariate analysis—passed away December 20, 2025.
Obituary: Estelle Bee Dagum
Estelle Bee Dagum, a Fellow of the ASA and a pioneering statistician, whose work transformed the practice of official statistics, passed away April 2, 2026.
Obituary: Norman Phillip Ross
Norman Phillip Ross, pioneering chief statistician of the US Environmental Protection Agency and ASA fellow, passed away in November, leaving a legacy in environmental statistics and public health.
Obituary: James Hunter Clair
Jim Clair passed away in October. He enjoyed snowboarding, surfing, and puzzles. He also raised two scarlet macaws, caring for them for more than 47 years.
Obituary: Stephen Portnoy
Longtime ASA member and Fellow Stephen Portnoy passed away December 28, 2025.
Obituary: Richard Arnold Johnson
Richard Arnold Johnson, aged 88, died on February 2, 2026. He lived a rich life of service and contributed greatly to the profession of statistics.