Preference Formation and Peer Effects in University Admission: The Further Deferred Acceptance

就研究如何改善现实生活中的实践而言，市场设计一直是经济学中最成功的领域之一。作为一种认可，2012年诺贝尔经济学奖授予了阿尔文·罗斯（Alvin Roth）和劳埃德·沙普利（Lloyd Shapley），以表彰他们“稳定配置理论和市场设计实践”。然而，仍有许多尚未解决的研究问题和实际问题。本研究旨在通过关注两个悬而未决的问题，提高我们对大学录取市场设计的理解。首先，通常假设学生可以免费对所有大学进行偏好排名。其次，文献大多不考虑外部性，如同伴效应。不幸的是，这两个假设在实际应用中都不太可能得到满足。例如，学生通常会从大量的选项中进行选择，而他们对这些选项的信息有限，因此很难制定一个完整的偏好排名。此外，学生可能更喜欢在他们的朋友被录取的大学附近学习。德国最近引入了一种新机制，以解决标准假设不成立时可能出现的问题。我们的项目研究了这种机制，它是延迟接受（DA）机制的一种变体（Gale和Shapley， 1962）。由于其理想的理论特性，如稳定性和抗策略性，DA一直处于市场设计的核心，并已被采用在许多教育环境中，如波士顿，纽约和巴黎的学校选择。与DA相比，德国的机制有两个重要特点：首先，系统中的学生“申请”一组大学，只有在大学发出第一轮录取通知后才需要对这些大学进行排名。其次，学生可能会收到多个首轮录取通知，他们可以决定留下哪一个。与DA相比，排名决定和接受/拒绝第一轮报价的时间进一步推迟。因此，我们称之为进一步延期接受（FDA）机制。我们建立了一个模型来说明，如果偏好形成是昂贵的和/或同伴效应存在，FDA在学生福利方面支配DA。该模型的两个组成部分在文献中都是非标准的。为了对这些假设进行实证检验，我们使用了调查、管理和实验数据。FDA相对于DA的表现也将通过反事实分析进行定量评估，即基于估计偏好模拟两种机制下的结果。这个项目将调查一个市场设计解决方案，当申请人不确定他们的偏好，当偏好受到同伴的影响。我们的项目将利用理论和数据，为FDA支配DA的情况提供证据。考虑到从DA转换到FDA的低成本，这可以在许多现实环境中成为一种选择。

Market design has been one of the most successful fields of economics in terms of how research has improved practices in real life. As a recognition, the 2012 Nobel Prize in Economics was awarded to Alvin Roth and Lloyd Shapley "for the theory of stable allocations and the practice of market design". However, many unresolved research questions and practical problems remain. This research aims to advance our understanding of market design for university admission by focusing on two open questions. First, it is typically assumed that students can form a preference ranking of all universities at no cost. Second, the literature mostly does not allow for externalities such as peer effects. Unfortunately, both assumptions are unlikely to be satisfied in real applications. For example, students usually choose from a large set of options about which they have limited information, and thus have difficulties to formulate a full preference ranking. Also, students may prefer to study close to where their friends are admitted to university.A new mechanism that was recently introduced in Germany addresses the problems that can arise when the standard assumptions do not hold. Our project investigates this mechanism which is a variant of the Deferred-Acceptance (DA) mechanism (Gale and Shapley, 1962). Due to its desirable theoretical properties such as stability and strategy-proofness, the DA has been at the very center of market design, and it has been adopted in numerous educational settings such as school choice in Boston, New York City, and Paris. In contrast to the DA, the German mechanism has two important features: First, students in the system "apply to" a set of universities and are only required to rank them after universities make first-round offers. Second, students may receive multiple first-round offers and can decide which one to keep. Compared with the DA, the ranking decision and the acceptance/rejection of first-round offers are further deferred. Hence, we call it the Further-Deferred-Acceptance (FDA) mechanism. We build a model to illustrate that the FDA dominates the DA in terms of student welfare if preference formation is costly and/or peer effects exist. Both ingredients of the model are non-standard in the literature. To empirically test these assumptions, we use survey, administrative, and experimental data. The performance of the FDA relative to the DA will also be evaluated quantitatively by counterfactual analyses, i.e. by simulating outcomes under both mechanisms based on estimated preferences.This project will investigate a market design solution when applicants are uncertain about their preferences and when preferences are affected by peers. Our project will provide evidence on the conditions under which the FDA dominates the DA, using both theory and data. Given the low cost of switching from the DA to the FDA, this can be an option in many real-life contexts.