Professor Richard Allen Olshen passed away on November 8, 2023.
Professor Olshen will be forever remembered for his pioneering research in the field of statistics and his unyielding passion for academia, especially to Stanford University. He played a significant role in advancing statistical learning, notably through his influential work on regression and classification trees. His well-known book Classification and Regression Trees described the motivation, algorithms and mathematical theory of CART. His internationally acclaimed and pioneering work spanned various domains, including gait analysis, digital radiography, and, in more recent years, molecular genetics.
As the division chief of Biostatistics in the Department of Health Research and Policy, his leadership, especially in the shaping of biostatistics at Stanford, will be fondly remembered. Professor Olshen was a key figure in the development of the Biostatistics Workshop (predecessor to the weekly department seminar series in DBDS) and Data Studio. His many contributions will leave a lasting imprint on Stanford’s School of Medicine and Stanford University.
Richard Olshen was born in Portland, Oregon, on May 17, 1942. After completing his undergraduate training at UC Berkeley, he attended Yale University, where he earned his PhD in Statistics in 1966 under the guidance of L.J. Savage. In 1967, he moved to Stanford University, beginning a long connection with the institution. In 1975 he joined the faculty of the Mathematics Department at UC San Diego, returning to Stanford in 1989.
Richard Olshen was a passionate mentor to many. In addition to his academic accomplishments, Richard was also a dedicated husband, nurturing father, and doting grandfather. Although we deeply mourn his loss, his influence on our field and the memories of his wisdom and candor will remain as an everlasting tribute. We will provide further information on how to honor his memory with his family once it becomes available. In lieu of flowers, the family prefers donations in honor of his memory to the charity of your choice.

Written by Sylvia K. Plevritis, Professor and Chair, Department of Biomedical Data Science, Stanford University; and Adam Olshen, Department of Epidemiology and Biostatistics, University of California, San Francisco. This obituary is based on this text and is reproduced by permission of Adam Olshen. A longer obituary by Jennifer Welsh appears here.