The statistical division of the FHA prepared real property inventories which charted, among other things, the racial content of cities across the country and the link between race and the likelihood of foreclosure on mortgage development. "Redlining" maps, coding areas inappropriate for mortgage insurance and largely coinciding with the location of racial populations, were then prepared in FHA offices across the country. Largely following received directives from traditional methods of real estate development, FHA philosophy as it appeared in Technical Bulletins, underwriting manuals and other publications clearly encouraged homogeneity and exclusion.
"A Realtor should never be instrumental in introducing in a neighborhood a character of property or occupancy, members of any race or nationality, or any individual whose presence will clearly be detrimental to property values in the neighborhood." From the National Association of Real Estate Boards-code of ethics
"...But building and real estate men ever since the 1920's had advocated racial segregation. Up to 1950, the code of ethics of the National Association of Real Estate Boards imposed an obligation on Realtors to keep minorities out of new neighborhoods. Dozens of texts and more than hundred real-estate courses in colleges from coast to coast emphasized that when non-white families go where they are not wanted, they threaten real estate values and become undesirable neighbors.
The FHA and the Home Loan Bank Board adopted these policies and from 1935-1949 openly advocated racial segregation of minorities, the barring of 'inharmonious groups' from new neighborhoods, restrictive covenants, and other exclusion devices. The official manual of the FHA during the period read like a chapter from Hitler's Nuremberg laws. 
Stanley L. McMichael, Real Estate Subdivisions (New York: Prentice-Hall, 1949), p.209.
 Charles Abrams, The Reporter, 9 May 1954.