Herman Rubin

Born in 1926 in Chicago, Illinois, Rubin was considered a child prodigy^{[according to whom?]} who earned his undergraduate and graduate degrees from the University of Chicago, completing his doctorate in mathematics at the age of 21 in 1948; his official advisor was Paul Halmos. He served in the U.S. Army during the Second World War.^[3] Prior to joining Purdue University in 1967, Rubin held faculty positions at several other prestigious institutions (Stanford University,^[4] the University of Oregon, and Michigan State University).

Rubin was considered a polymath with a unique ability to solve complex problems. He was a prolific researcher, publishing over 130 papers that have become standard texts in various fields. His key contributions include:

• Multivariate Analysis: He co-authored seminal papers with T.W. Anderson on the distribution theory of maximum likelihood estimators in factor analysis and structural equation models.
• Monotone likelihood ratio: He is credited with the widely used and fundamental concept of monotone likelihood ratio families.
• Bayesian Inference: Rubin was a lifelong Bayesian statistician who took the theory and axioms of Leonard Jimmie Savage literally, and he contributed significantly to the theory of Bayes risks.
• Econometrics: He worked on problems related to the simultaneous equations model in economics, including the development of the Limited information maximum likelihood (LIML) estimator.
• Set Theory and Probability: His work also included contributions to set theory, the theory of moderate deviations, and the characterization of probability distributions.
• Hypothesis testing: in collaboration with Samuel Karlin, the Karlin-Rubin theorem provides a method for finding uniformly most powerful tests for one-sided hypotheses, a significant contribution to the theory of hypothesis testing.

He was an inaugural Fellow of the American Mathematical Society and a Fellow of the Institute of Mathematical Statistics.

He was married to Jean E. Rubin (1926–2002), a professor of mathematics at Purdue University whose primary research focus was on the axiom of choice.^[5] His son Arthur Rubin (born 1956) is a mathematician and aerospace engineer.

Over his career, Herman Rubin supervised at least eleven doctoral students,^[6] was highly respected by his colleagues and was known for his generosity in helping others with their research problems without seeking credit.^[7] A memorial lecture series, the Herman Rubin Memorial Lecture, was established at Purdue University in his honor.^[8]