Blanch became technical director of the Mathematical Tables Project, leading a major WPA-era human-computing operation in New York.
By June 1938, Gertrude Blanch had become technical director of the Mathematical Tables Project in New York City, a Works Progress Administration program that employed a large staff of human computers. Although the exact day is not preserved in the sources, the appointment marked a decisive moment in the history of American computation. Blanch’s leadership transformed the project into the largest and most sophisticated human-computing organization in the United States.
Her role was historically significant because she was not merely supervising clerical calculation. She was organizing algorithms, coordinating workers, standardizing procedures, and shaping the literature of numerical analysis at a time when the field was still coming into its own. In practical terms, this meant converting mathematical problems into step-by-step procedures that could be carried out reliably by teams of workers, many of whom had little formal mathematical training. That work helped lay the foundations for later programming practice.
The appointment also reflects the barriers women mathematicians faced in the Depression era. Universities and research institutions often denied women stable professional posts, so large-scale government computation became one of the few places where a woman with advanced training could exercise authority. Blanch used that opportunity to build an influential computational culture that fed wartime science, military tables, and the emerging discipline of numerical analysis.