School choice systems across the United States have increasingly adopted common applications, where students apply to multiple schools through a single form even though each school makes admissions decisions independently. Proponents argue these systems reduce logistical barriers, expand information access, and level the playing field for disadvantaged families. Yet it remains an open question whether common applications actually improve student-school matching relative to the alternatives.
Christopher Avery, Geoffrey Kocks, and Parag Pathak address this question by developing a model that compares three application systems — decentralized (where each application carries a cost), common application, and ranked-choice (where students rank schools and a matching algorithm generates placements). Their theoretical analysis shows that while common applications expand access by lowering application costs, this benefit is offset by intensified competition that can produce worse matches than decentralized systems, where application costs naturally induce students to apply more selectively. Ranked systems, by contrast, preserve low application costs while using preference-based matching to minimize mismatches.
The authors test these predictions using data from Boston's charter school sector before and after its adoption of a common application system. A key empirical finding is that student preferences are not stable between application and enrollment: a school ranked first at application remains the top choice only 72% of the time at enrollment. Accounting for this preference instability, both the common application and decentralized systems place 36% of students in their first-choice school, while simulations of a ranked system would have achieved 39%. Contrary to a primary policy goal, Boston's common application did not improve school access for disadvantaged student groups. Counterfactual simulations using a structural demand model confirm that the ranked system consistently outperforms the common application on both first-choice placement rates and overall student welfare across varying levels of market competition and preference instability.
- Working Paper: https://www.nber.org/papers/w3...