Segregation and school composition in Washington, DC following the implementation of a unified school lottery

The global expansion of choice programmes fuels debates about the equity potential of school choice policies and mechanisms. In 2014, Washington, D.C. pioneered a citywide lottery and enrolment system to match students with preferred institutions and distribute access to seats in high-demand schools. While unified lottery and enrolment systems impact a vast number of students and influence educational opportunities across continents, little evidence exists on the efficacy of these systems or the link between centralized lotteries and changes in school composition or segregation. Using longitudinal data and an interrupted time series analysis, this study examines the relationship between D.C.'s centralized lottery system and student distribution. We find unchanged desegregation trends systemwide and annual increases in segregation in schools located in wealthier and lower-income wards after the adoption of the lottery system. We raise questions about the way school-designated preference structures give the appearance of numerous school options for families, while keeping access to meaningful choices superficial. Across international contexts, these systems may aid desegregation efforts and enhance equity by randomizing school matches, preventing cream skimming, and offering a baseline of school information, but additional research is needed to better understand their substantive outcomes.