Herman Chernoff

Herman Chernoff was born in New York City on 1 July 1923 to Pauline (Markowitz) and Max Chernoff, Jewish immigrants who had been born and raised in the Russian Empire. He grew up in the Bronx during the Great Depression in a family of modest means, alongside his sister Lillian. After his father's death his mother married Louis Groh. A gifted pupil, he was invited to sit the competitive entrance examinations for Townsend Harris High School, a prestigious preparatory school for the City College of New York, and won a place.

Chernoff earned a BS in mathematics with a minor in physics from the City College of New York in January 1943, where two statistics courses and a weekend spent puzzling over a Neyman and Pearson paper first drew him toward the subject. After wartime service as a junior physicist for the US Navy, he entered Brown University, studying under Bers, Feller, Loewner and Tamarkin, and earned an MSc in applied mathematics in 1945 with a dissertation on complex solutions of partial differential equations. After a summer statistics course in North Carolina with R. A. Fisher, William Cochran and Jacob Wolfowitz, he asked Abraham Wald to supervise his doctorate. His thesis, Asymptotic Studentization in Testing of Hypotheses, earned him a PhD in applied mathematics from Brown in 1948.

Chernoff worked as a research instructor at the Cowles Commission for Research in Economics at the University of Chicago (1947 to 1949), then taught mathematics at the University of Illinois at Urbana (1949 to 1952). He joined Stanford University in 1952, became professor of statistics in 1956, later chaired the department and stayed until 1974. At Stanford he introduced the Chernoff bound (1952), co-wrote Elementary Decision Theory with Lincoln Moses (1959), developed the Chernoff-Savage theorem in nonparametric statistics, published Sequential Analysis and Optimal Design (1972) and created Chernoff faces (1973). He moved to MIT in 1974 as professor of applied mathematics and founded its statistics centre, then joined Harvard's Department of Statistics in 1985, retiring in 1997 as professor emeritus at both Harvard and MIT. His research spanned large sample theory, experimental design, sequential analysis, visual display of data and statistical decision making, and in later years he also wrote Algebra I for Students Comfortable with Arithmetic (2001).

Chernoff met Judith (Judy) Ullman when both were graduate students at Brown University in 1945, and they married in September 1947. They had two daughters, Ellen and Miriam. He later said the happiest time of his life was raising his young family in California, with trips to the beaches, Yosemite, Disneyland and the Sierra Nevada ski slopes. On a 1960 sabbatical he took the family to London and Rome, returning via Israel, India, Thailand and Japan. In Boston the couple became part of the Jewish community in Brookline and later lived at Springhouse in Jamaica Plain. Judy died on 9 June 2023 aged 98, after more than 75 years of marriage.

Chernoff believed statistics should connect theory to real decisions. He said Abraham Wald's work converted him because it treated a statistical conclusion as something with real-world consequences. Late in life he described himself as an applied statistician at heart, saying his theoretical insights came from thinking about applied problems. He valued mentoring young researchers, clear communication and careful scheduling, and remained intellectually curious to the end, trying to understand quantum mechanics in his last years.

The Chernoff bound remains a standard citation in randomized algorithms, information theory and machine learning, a piece of 1952 mathematics still used daily in software. Chernoff faces are still taught as an early argument that charts should be built for the human eye. Elementary Decision Theory stayed in print for more than 60 years. His suggestion of an annual New England Statistics Symposium in 1987 eventually led to the New England Statistical Society, whose top honour, the Chernoff Excellence in Statistics Award, bears his name. Generations of doctoral students and colleagues credit him with shaping their careers.

President of the Institute of Mathematical Statistics (1967); Fellow of the American Academy of Arts and Sciences (1974); member of the National Academy of Sciences (1980); Samuel S. Wilks Memorial Award, American Statistical Association (1987); inaugural Fellow of the American Mathematical Society (2012); Fellow of the American Statistical Association and the Institute of Mathematical Statistics; member of the International Statistical Institute; honorary doctorates from Ohio State University, the Technion, Sapienza University of Rome and the University of Athens; Chernoff Excellence in Statistics Award named in his honour (2019); City College of New York Division of Science Distinguished Alumni award (2021); Emanuel and Carol Parzen Prize for Statistical Innovation, Texas A&M (2022).

Chernoff appears in two 1989 American Statistical Association recordings, The History of Sequential Analysis: Some Reminiscences and A Conversation with Herman Chernoff with F. Anscombe, W. DuMouchel and A. Gelfand. John Bather's interview A Conversation with Herman Chernoff appeared in Statistical Science in 1996. He spoke at City College's 2021 Distinguished Alumni event and gave a colloquium on receiving the Parzen Prize at Texas A&M in 2022. WCVB Boston featured Herman and Judy Chernoff as believed to be the oldest living couple in Massachusetts.

Herman Chernoff died peacefully in Boston, Massachusetts, on 6 July 2026, aged 103, five days after his birthday. A specific cause of death was not made public. Arrangements were handled by Stanetsky Memorial Chapel. Tributes came from Stanford's Department of Statistics, the New England Statistical Society, the Royal Statistical Society and many colleagues and former students.