What matters in school choice tie-breaking? How competition guides design
نویسندگان
چکیده
Many school districts apply the student-proposing deferred acceptance algorithm after ties among students are broken exogenously. We compare two common tie-breaking rules: one in which all schools use a single common lottery, and one in which every school uses a separate independent lottery. We identify the balance between supply and demand as the determining factor in this comparison. First we analyze a two-sided matching model with random preferences in over-demanded and under-demanded markets. In a market with a surplus of seats a common lottery is less equitable and there are efficiency trade-offs between the two tie-breaking rules. However, a common lottery is always preferable when there is shortage of seats. The theory suggests that popular schools should use a common lottery to resolve ties. We run numerical experiments with New York City choice data after partitioning the market into popular and non-popular schools. The experiments support our findings.
منابع مشابه
Electronic Companion to: What matters in school choice tie-breaking? How competition guides design
We break Theorem 3.2 into several smaller (sub-)theorems and prove each one separately. This is done in sections 1.1, 1.2, and 1.3, which state and discuss the theorems about stochastic dominance, Pareto improving pairs, and variance, respectively. The theorems stated in these sections are then proved separately in the later sections. Section 2 contains the proofs for stochastic dominance. Sect...
متن کاملWhat matters in tie-breaking rules? How competition guides design PRELIMINARY DRAFT
School districts that adopt the Deferred Acceptance (DA) mechanism to assign students to schools face the tradeoff between fairness and efficiency when selecting how to break ties among equivalent students. We analyze a model with with random generated preferences for students and compare two mechanisms differing by their tie-breaking rules: DA with one single lottery (DA-STB) and DA with a sep...
متن کاملAssigning more students to their top choices: A comparison of tie-breaking rules
School districts that implement stable matchings face various decisions that affect students’ assignments to schools. We study properties of the rank distribution of students with random preferences when schools use different tie-breaking rules to rank equivalent students. Under a single tie-breaking rule, where all schools use the same ranking, a constant fraction of students are assigned to o...
متن کاملHow to Do Tie-breaking in Prioritization of Interaction Test Suites?
The prioritization of interaction test suites has received more attention in the field of combinatorial interaction testing, especially when testing resources are limited to allow the part of combinatorial test cases to be executed. Many strategies have been proposed to prioritize interaction test suites according to different evaluation measures. However, most of these strategies may face a ch...
متن کاملCentralized Clearinghouse Design: a Quantity-quality Tradeoff
Stable matching mechanisms are used to clear many two-sided markets. In practice, these mechanisms leave many agents on both sides unmatched. What factors determine the number of unmatched agents, and the quality of matches that do form? This paper answers these questions, with a particular focus on how match outcomes depend on correlations in agent preferences. I consider three canonical prefe...
متن کامل