After being awarded a Rosenwald Fellowship, established by the clothing magnate Julius Rosenwald to aid black scholars, he attended the Institute for Advanced Study at Princeton but left after a year when, because of his race, he was not issued the customary invitation to become an honorary faculty member. At Berkeley, where the statistician Jerzy Neyman wanted to hire him in the mathematics department, racial objections also blocked his appointment.

Instead, Mr. Blackwell sent out applications to 104 black colleges on the assumption that no other schools would hire him. After working for a year at the Office of Price Administration, he taught briefly at Southern University in Baton Rouge, La., and Clark College in Atlanta before joining the mathematics department at Howard University in Washington in 1944.

Obituary of David Blackwell, NYT, ht Andrew Gelman