 Suburbanization became connected with white flight by this time, because whites were better established economically to move to newer housing.The situation was perpetuated by real estate agents' continuing racial discrimination.In particular, from the 1930s to the 1960s, the National Association of Real Estate Boards (NAREB) issued guidelines that specified that a realtor "should never be instrumental in introducing to a neighborhood a character or property or occupancy, members of any race or nationality, or any individual whose presence will be clearly detrimental to property values in a neighborhood."