Richard A. Olshen

Also known as Richard Allen Olshen, Richard Olshen

Richard Olshen was a Stanford statistician who co-developed CART, the classification and regression tree method used in machine learning and medical prediction. After a Berkeley degree in 1963 and a Yale PhD in 1966, he held faculty posts at Stanford, the University of Michigan and UC San Diego. He began work on CART in 1974 at the Stanford Linear Accelerator Center and published Classification and Regression Trees in 1984 with Leo Breiman, Jerome Friedman and Charles Stone. Back at Stanford from 1989, he worked with Robert Gray on image compression and led the biostatistics division from 1998 until 2016. A Fellow of the Institute of Mathematical Statistics, the American Statistical Association, the AAAS and the IEEE, and a Guggenheim Fellow, he died in 2023 at age 81.

Born: 1942
Died: 2023
Works: 197
Badges: Loyal
Pioneer

Years link to their sources. Publication numbers from OpenAlex, as of 22 October 2026. Citations and h-index are hidden because this OpenAlex record may be incomplete or mix in other authors.

Timeline

1963–1966

Berkeley and a Yale PhD

He earns an A.B. in statistics at the University of California, Berkeley, in 1963. In 1966, he completes a Ph.D. in statistics at Yale University, with a dissertation written under Jimmie Savage and Frank Anscombe.
1967–1989

Professor at Michigan and UC San Diego

He accepts a faculty appointment at Stanford in 1967, then holds tenured faculty positions at the University of Michigan from 1972 to 1975 and at UC San Diego from 1975 to 1989. At UC San Diego, he helps found what becomes the Moores Cancer Center.
1974

Starting CART at SLAC

He starts work on CART in 1974 as a member of the Computation Research Group at the Stanford Linear Accelerator Center, where Jerry Friedman is his boss. CART is a recursive-partitioning method in machine learning: a computer-based decision tree predicts an outcome from input values, and such trees are used to classify patients. He goes on to develop its binary tree-structured methods for classification, regression and probability class estimation, with extensions to survival analysis and clustering.
1984

The CART book

In 1984, he coauthors Classification and Regression Trees with Leo Breiman, Jerome Friedman and Charles Stone. The book gives the motivation, algorithms, various examples and mathematical theory for what become known as CART algorithms.
1989

Image compression with Robert Gray

He returns to Stanford in 1989 as a professor of biostatistics. Robert Gray, a Stanford electrical engineering professor, invites him to collaborate on image compression, since the pruning algorithm in the CART book applies to the problem. Their studies cover CT images of lung masses, MR images of blood flow in the chest and digital mammography.
1998–2016

Chief of Stanford biostatistics

He is chief of the biostatistics division in Stanford's Department of Health Research and Policy from 1998 until 2016, then joins the Department of Biomedical Data Science. As division chief, he helps shape biostatistics at Stanford and is a key figure in building the biostatistics workshop and data studio.
By 2015

Four society fellowships and a Guggenheim

By 2015, he is an elected Fellow of the Institute of Mathematical Statistics, the American Statistical Association, the American Association for the Advancement of Science and the IEEE. He is also a former Guggenheim Fellow and a Research Scholar in Cancer of the American Cancer Society.
November 2023

Death at age 81

After retiring in 2016 at age 74, he keeps mentoring colleagues and works on a molecular genetics project with Lu Tian. He dies in November 2023 at age 81, an emeritus professor of biomedical data science at the Stanford School of Medicine.