To what extent do politicians reward voters who are members of their own ethnic or racial group? Using data from large cities in the United States, we study how black employment outcomes are affected by changes in the race of the cities’ mayors between 1973 and 2004. We find that relative to whites, black employment and labor force participation rise, and the black unemployment rate falls, during the tenure of black mayors. Black employment gains in municipal government jobs are particularly large, which suggests that our results capture causal effects of black mayors. Black mayors also lead to higher black incomes relative to white incomes. We show that our results continue to hold when we compare the treated cities to alternative control groups of cities, explicitly control for changing attitudes towards blacks or use regression discontinuity analysis to compare cities that elected black and white mayors in close elections.That is from a paper by John V.C. Nye, Ilia Rainer, & Thomas Stratton (The Journal of Law, Economics & Organisation, April 2014). A draft (2010) is here.
The authors suggest ideas for research (p. 41):
While we show that urban blacks benefit from having a black mayor in office, we do not have enough evidence to assess the overall impact of black mayors on social welfare. In particular, it remains unclear whether improvements in the condition of urban blacks were a result of the efficiency-enhancing removal of previous discrimination against blacks or whether they were a result of new discrimination in favor of blacks. It is also possible that gains to blacks came at the expense of other groups. Although our results suggest that gains to urban blacks were not accompanied by losses to urban whites, these gains could still represent a rent transfer from rural workers, taxpayers or business investors.