Black History Month Highlight: Dr. David Blackwell

By Elaona Lemoto

For Black History Month this year, students in the Biostatistics PhD program will highlight a Black statistician or biostatistician each week who has made tremendous contributions to the field. Dr. David Blackwell has been selected for this week. 

 Dr. David Blackwell was an extraordinary mathematician and statistician who made advantageous gains in probability theory, game theory, and Bayesian inference. 

Dr. Blackwell was born in 1919 in Centralia, Illinois. He found a passion for mathematics in high school which then lead to an interest in studying mathematics in college, and then earning his PhD in mathematics at the age of 22 at the University of Illinois at Urbana-Champaign. His doctoral thesis explored properties of Markov chains and was advised by Dr. Joseph Doob.

In 1941, Dr. Blackwell received a Rosenwald Fellowship at the Institute for Advanced Study at Princeton. Though he was quite accomplished at this point of his career, racial discrimination barred him from setting foot in Fine Hall, then Princeton’s mathematics building. 

From 1941 to 1942, Blackwell wrote some 105 letters of application, all to black colleges. Eventually he received three job offers. He accepted the position of instructor at Southern University in Baton Rouge in 1942. The following year he moved on to an instructorship at Clark College, Atlanta. Finally in 1944 David obtained a regular appointment at Howard University, in the District of Columbia. He remained there until 1954, at which time he had become a professor and department chair. During his tenure at Howard, he  published the paper "Conditional Expectation and Unbiased Sequential Estimation", which outlined a technique that later became known as the Rao-Blackwell theorem. The theorem provides a method for improving statistical estimates by potentially reducing their mean squared error.  

From 1948 to 1950, Blackwell spent his summers at RAND corporation with Meyer Abraham Girshick and other mathematicians exploring the game theory of duels. In 1954 Girshick and Blackwell published Theory of Games and Statistical Decisions.  Aside from von Neumann and Girshick, other collaborators and mentors included Leonard J. Savage, Richard E. Bellman, and Nobel Laureate Kenneth J. Arrow. 

Finally in 1954 at Jerzy Neyman's invitation, Blackwell began as a visiting professor at the University of California, Berkeley. In 1955, Blackwell was appointed a professor of statistics at Berkeley. At the time of that appointment, he had published some 20 papers appearing in the major mathematics and statistics journals.

Blackwell's Berkeley years were very busy. He became department chair in 1957 and was a member of many professional committees, some of them being American Association for the Advancement of Science, American Mathematical Society, American Statistical Association, International Congress of Mathematicians, Institute of Mathematical Statistics, Mathematical Association of America, and National Research Council. He hit his next milestone in 1965 when he became the first black scholar admitted to the National Academy of Sciences. The possibility of admission wasn’t even on his radar.

Dr. Blackwell continued to publish influential work after his tenure and major appointments . In 1967 he bridged topology and game theory via a game-theoretic proof of Kuratowski's theorem in 1967. Then in 1969, he wrote one of the first Bayesian textbooks, Basic Statistics. It inspired the 1995 textbook Statistics: A Bayesian Perspective by the biostatistician Donald Berry. Blackwell’s broad interests, including pure as well as applied mathematics, led to his additional appointment at Berkeley in 1973 as professor of mathematics.