π€ AI Summary
This study addresses the high costs of exhaustive verification in centralized school admissions and the risks associated with ex post sampling. Drawing on mechanism design and game theory, we leverage the deferred acceptance algorithm to propose a method for identifying pivotal claims, establishing the principle of verifying decisions rather than documents. Specifically, our approach selectively verifies only those priority claims whose falsification could alter admission outcomes. We demonstrate that this method strictly preserves the original admission results while reducing the verification workload by 76% compared to exhaustive checking and by 36% relative to school-by-school verification. By reconciling efficiency with reliability, this work offers a novel paradigm for verification in centralized admission systems.
π Abstract
Centralized admissions platforms grant priority based on self-reported facts such as residence, sibling status, or family income, and a false claim can cost another applicant her seat. Verifying every claim before matching is expensive, yet checking only admitted applicants afterward is unsafe: a false claim by an applicant who ends up unmatched may already have triggered a chain of rejections. We show how a platform can check far fewer claims without changing any outcome. A claim matters only if it can move its applicant across a school's admission cutoff, and we give an exact, easily computed test for when this happens. Checking only such claims, and only when they could change a school's tentative choice, reproduces every application, rejection, and assignment of deferred acceptance under full verification. When claims are truthful, checking the highest claimed priority first minimizes checks among such policies at each school decision, and the number of checks never exceeds the school's capacity. Truthful reporting of preferences and eligibility is a weakly dominant strategy, so incentives deliver the conditions under which this audit order is optimal. In simulated markets, the policy cuts verification by 76 percent relative to checking every claim upfront and by 36 percent relative to checking each claim when it first reaches a school. The design principle is to verify decisions, not files.