How Are Lotteries Used in Student Assignment?
School Assignment, June 2010
Parag Pathak and Jay Sethuraman investigate a simplified method for understanding how lotteries are used in assigning students to schools. This work stems from design of new student assignment mechanisms coupled with interests by policymakers from authorities such as the NYC Department of Education. Here Pathak and Sethuraman uncover that single and multiple lottery mechanisms are equivalent for the problem of allocating students to schools in which students have strict preferences and the schools are indifferent.
School districts around the world employ centralized mechanisms to assign students to schools. These processes of assigning students consider factors such as student priorities at individual schools (such as geographic proximity) along with applicants rank ordering of schools. Upon consideration of this model, a key question is raised: if many students rank the same school as their top choice, which of these students should be assigned to that school? A lottery mechanism is a way to achieve fairness in the assignment process. Pathak and Sethuraman examine single versus multiple lottery mechanisms with consideration of assignment problems motivated by DOE discussion.