Census data show that the ratio of black to white unemployment rates, currently in excess of 2:1, was small or nonexistent before 1940, widened dramatically during the 1940s and 1950s, and widened again in the 1980s. The authors decompose changes in the unemployment gap over the years...

Although the substantial and persistent gap between the unemployment rates of African-Americans and whites in the United States first emerged in aggregate statistics covering the 1940s and 1950s, disaggregation reveals that the gap already existed in urban areas before 1940. Using...