Doob was awarded a AB by Harvard in 1930 and asked his advisor Marshall Stone if he would supervise his doctorate. Stone suggested that he would be better with J L Walsh as his supervisor.
Doob ay iginawad ng AB sa pamamagitan ng Harvard sa 1930 at nagtanong ang kanyang mga taga-payo Marshall Stone kung siya ay asikasuhin ang kanyang titulo ng doktor. Stone iminungkahi na siya ay magiging mas mahusay sa JL Walsh bilang kanyang tagapamahala.