The paper by Claudia Cerrone, Yoan Hermstrüwer, and Onur Kesten explores the efficiency-adjusted deferred acceptance (EADAM) mechanism in school choice, a mechanism designed to balance efficiency and fairness. The authors provide the first experimental evidence on the performance of EADAM compared to the traditional deferred acceptance (DA) mechanism. They find that EADAM generally yields higher efficiency and truth-telling rates than DA, despite not being strategy-proof. The study also examines the impact of different default rules for priority waivers and the enforcement of priority waivers, revealing a trade-off between efficiency and vulnerability to preference manipulation. The results challenge the importance of strategy-proofness as a prerequisite for truth-telling and suggest that non-strategy-proof mechanisms can still achieve high truth-telling rates. The findings have implications for policy makers and school authorities looking to implement school admission procedures that balance stability and efficiency.The paper by Claudia Cerrone, Yoan Hermstrüwer, and Onur Kesten explores the efficiency-adjusted deferred acceptance (EADAM) mechanism in school choice, a mechanism designed to balance efficiency and fairness. The authors provide the first experimental evidence on the performance of EADAM compared to the traditional deferred acceptance (DA) mechanism. They find that EADAM generally yields higher efficiency and truth-telling rates than DA, despite not being strategy-proof. The study also examines the impact of different default rules for priority waivers and the enforcement of priority waivers, revealing a trade-off between efficiency and vulnerability to preference manipulation. The results challenge the importance of strategy-proofness as a prerequisite for truth-telling and suggest that non-strategy-proof mechanisms can still achieve high truth-telling rates. The findings have implications for policy makers and school authorities looking to implement school admission procedures that balance stability and efficiency.