In the 1920s, the Chicago Real Estate Board established a racially restrictive covenant policy in response to the rapid influx of southern black migrants who were allegedly feared in bringing down property values of white neighborhoods. Contractual agreements among property owners included prohibiting sale or lease of any part of a building to specific groups of people, usually African Americans. For the next few decades, blacks were prevented from purchasing homes in certain white neighborhoods in Chicago. Although highly skilled African Americans gained unprecedented access to city jobs, they were not given as many opportunities for work and were often left with less desirable positions, sometimes in dangerous or unpleasant settings. School boundary lines were carefully drawn to avoid integrating the Chicago Public Schools (CPS), and African American children attended all-black schools in overcrowded conditions, with less funding in materials. As a result, many black families were locked in the overcrowded South Side in shoddy conditions.