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解析文章首发于唧唧堂网站www.jijitang.com
解析作者 | 唧唧堂经济金融学研究小组：
Xinxin Chen
；审校编辑 |
悠悠 糖糖
1. 万有引力
摘要：我们研究了一大类一般均衡贸易和经济地理模型的理论性质和反事实预测。将总要素供求函数和市场出清条件相结合，我们证明了均衡的存在性、唯一性，以及在给定观测到的贸易流的情况下，这类模型的反事实预测仅取决于需求和供给弹性(“引力常数”)。用“模型暗含的”工具变量法，我们估计了引力常数，并且用这一估计计算了中美贸易战的影响。
Abstract: We study the theoretical properties and counterfactual predictions of a large class of general equilibrium trade and economic geography models. By combining aggregate factor supply and demand functions with market-clearing conditions, we prove that existence, uniqueness, and—given observed trade flows—the counterfactual predictions of any model within this class depend only on the demand and supply elasticities (“gravity constants”). Using a new “model-implied” instrumental variables approach, we estimate these gravity constants and use these estimates to compute the impact of a trade war between the United States and China.
参考文献：Treb Allen, Costas Arkolakis, and Yuta Takahashi, "Universal Gravity," Journal of Political Economy 128, no. 2 (February 2020): 393-433.
https://www.journals.uchicago.edu/doi/full/10.1086/704387
2. 亲社会性的形成:社会环境作用的因果证据
摘要：本研究为社会环境在亲社会性形成中的作用提供了证据。我们发现，社会经济地位、母子互动强度、母亲亲社会的态度与小学学生亲社会行为相关。我们也提供了“为孩子分配为期一年的导师”这一社会环境随机变动情况下的证据。数据显示，与对照组相比，处理组的亲社会性行为显著且持续增加。此外，丰富的社会环境也可缩小低社会经济地位的儿童和高社会经济地位的儿童之间的亲社会差异。中介作用检验表明，亲社会性是在亲社会的榜样效应和激烈的社会互动中发展起来的。
Abstract: This study presents evidence on the role of social environment for the formation of prosociality. We show that socioeconomic status (SES) as well as intensity of mother-child interaction and mothers’ prosocial attitudes are related to elementary school children’s prosociality. We also present evidence on a randomly assigned variation of the social environment, providing children with a mentor for 1 year. Our data reveal a significant and persistent increase in prosociality in the treatment relative to the control group. Moreover, enriching the social environment closes the prosociality gap between low- and high-SES children. A mediation analysis suggests that prosociality develops in response to prosocial role models and intense social interactions.
参考文献：Fabian Kosse, Thomas Deckers, Pia Pinger, Hannah Schildberg-Hörisch, and Armin Falk, "The Formation of Prosociality: Causal Evidence on the Role of Social Environment," Journal of Political Economy 128, no. 2 (February 2020): 434-467.
https://www.journals.uchicago.edu/doi/full/10.1086/704386
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3. 移动球门柱
摘要：我们研究了动态道德风险框架下，信息作为激励手段的问题。代理人要执行难度不确定性(以工作持续时间来表示)的任务。委托人知晓任务的难度，并逐渐提供信息。最优机制以移动的球门柱为特征: 一开始就告知任务难度，会使代理人乐观地认为任务非常简单。如果任务确实很困难，只有在代理人工作足够长的时间，将艰巨的任务完成的差不多后，才会告知代理人。即使委托人一开始并没有告知代理人任务的难度，代理人也会完成困难的任务。
Abstract: We study information as an incentive device in a dynamic moral hazard framework. An agent works on a task of uncertain difficulty, modeled as the duration of required effort. The principal knows the task difficulty and provides information over time. The optimal mechanism features moving goalposts: an initial disclosure makes the agent sufficiently optimistic that the task is easy. If the task is indeed difficult, the agent is told this only after working long enough to put the difficult task within reach. The agent then completes the difficult task even though he never would have chosen to at the outset.
参考文献：Jeffrey C. Ely and Martin Szydlowski, "Moving the Goalposts," Journal of Political Economy 128, no. 2 (February 2020): 468-506.
https://www.journals.uchicago.edu/doi/full/10.1086/704387
4. 政治繁荣，金融危机
摘要：政治繁荣(用政府受欢迎程度的上升来衡量)，可以预测金融危机，这一指标远远优于那些众所周知的早期预警指标，如信贷繁荣。然而，这一预测能力只适用于新兴经济体。我们认为，发展中国家的政府有更强的动机去利用不健康的信贷繁荣，以提高它们的受欢迎程度，而不是实施那些能够预防危机、但在政治上代价高昂的纠正性政策。我们通过构建基于民意调查的政府受欢迎程度的跨国数据集，提供了这一机制的证据。
Abstract: Political booms, measured by the rise in governments’ popularity, predict financial crises above and beyond better known early warning indicators, such as credit booms. This predictive power, however, only holds in emerging economies. We argue that governments in developing countries have stronger incentives to “ride” unsound credit booms in order to boost their popularity, rather than implementing corrective policies that could prevent crises but are politically costly. We provide evidence of the relevance of this mechanism, partly by constructing a new cross-country data set on government popularity based on opinion polls.
Political Booms, Financial Crises
参考文献：Helios Herrera, Guillermo Ordoñez, and Christoph Trebesch, "Political Booms, Financial Crises," Journal of Political Economy 128, no. 2 (February 2020): 507-543.
https://www.journals.uchicago.edu/doi/full/10.1086/704544
5. 弱条约的政治经济学
摘要：近几十年来，民主国家谈判达成了数百项国际条约和协定。本文分析了谋求连任的在位政治家进行条约谈判的均衡设计。我们发现，在任者倾向于谈判达成“软弱”的条约，因为他们可能会，也可能不会遵守: 这有利于在任政治家区分不同候选人的偏好。我们还发现，政治经济方面的考虑会引致过于雄心勃勃的条约，这些条约过于依赖技术，而不是制裁来激励合规。我们的理论可以解释与条约有关的若干难题。
Abstract: In recent decades, democratic countries have negotiated hundreds of international treaties and agreements. This paper analyzes the equilibrium design of treaties negotiated by political incumbents seeking reelection. We show that incumbents are prone to negotiate treaties that are “weak,” in that they may or may not be complied with: this makes it possible to differentiate the alternative candidates in a way that favors the incumbent. We also show that political economy considerations lead to overambitious treaties that rely too much on technology instead of sanctions to motivate compliance. Our theory can rationalize several puzzles associated with treaties.
参考文献：Marco Battaglini and Bård Harstad, "The Political Economy of Weak Treaties," Journal of Political Economy 128, no. 2 (February 2020): 544-590.
https://www.journals.uchicago.edu/doi/full/10.1086/704610
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6. 聘礼与女性教育
摘要：我们发现了聘礼(新郎向新娘家支付的费用)的一个重要结果。回顾印尼的学校建设项目，我们发现，在没有这一习俗的少数民族中，聘礼对女孩上学没有影响。在有这一习俗的民族中，它产生了很大的积极影响。我们证明(从理论和实证上)，女儿受教育程度越高，收到的聘礼就越多，就更能激励父母投资于女儿的教育。我们在赞比亚也发现了这一影响，该国也有类似的大规模学校建设项目。
Abstract:We document an important consequence of bride price, a payment made by the groom to the bride’s family at marriage. Revisiting Indonesia’s school construction program, we find that among ethnic groups without the custom, it had no effect on girls’ schooling. Among ethnic groups with the custom, it had large positive effects. We show (theoretically and empirically) that this is because a daughter’s education, by increasing the amount of money parents receive at marriage, generates an additional incentive for parents to educate their daughters. We replicate these findings in Zambia, a country that had a similar large-scale school construction program.
参考文献：Nava Ashraf, Natalie Bau, Nathan Nunn, and Alessandra Voena, "Bride Price and Female Education," Journal of Political Economy 128, no. 2 (February 2020): 591-641.
https://www.journals.uchicago.edu/doi/full/10.1086/704572
7. 学校选择模型的结构估计:波士顿机制与其他机制
我们在波士顿机制(BM)下建立了家庭选择学校的模型，并开发了一种适用于多种机制的新方法，使得在传统方法不可行的情况下，仍能充分解决选择难题。使用巴塞罗那的数据，我们估计了家庭偏好和家庭复杂程度类型(策略性或非策略性)的联合分布。反事实政策分析表明，从波士顿机制(BM)转换到延期接受算法(DA)，将使平均福利减少1020欧元，而转换到TTC算法，将使平均福利增加460欧元。
Abstract: We model household choice of schools under the Boston mechanism (BM) and develop a new method, applicable to a broad class of mechanisms, to fully solve the choice problem even if it is infeasible via the traditional method. We estimate the joint distribution of household preferences and sophistication types, using administrative data from Barcelona. Counterfactual policy analyses show that a change from BM in Barcelona to the deferred-acceptance mechanism would decrease average welfare by €1,020, while a change to the top-trading-cycles mechanism would increase average welfare by €460.
参考文献：Caterina Calsamiglia, Chao Fu, and Maia Güell, "Structural Estimation of a Model of School Choices: The Boston Mechanism versus Its Alternatives," Journal of Political Economy 128, no. 2 (February 2020): 642-680.
https://www.journals.uchicago.edu/doi/full/10.1086/704573
8. 投资阻塞问题中的信息设计
摘要：我们分析了一个双边贸易模型，在这个模型中，买方选择她对商品估价的分布。卖方观测到买方的估价分布但在估价没有落实之前，提出要么接受要么放弃(take-it-or-leave-it)的报价。如果分布是无成本的，那么在唯一均衡结果中，买卖双方的价格和收益都是1/e。买方的均衡分布会产生单位弹性需求，且交易是事后有效的。即使不同分布有不同的成本，只要成本是分布离差(即风险)的增函数，这些性质也会被保留下来。
Abstract: We analyze a bilateral trade model where the buyer chooses the distribution of her valuation for the good. The seller, after observing the buyer’s distribution but not the realized valuation, makes a take-it-or-leave-it offer. If distributions are costless, the price and the payoffs of both the buyer and the seller are shown to be 1/e in the unique equilibrium outcome. The buyer’s equilibrium distribution generates a unit-elastic demand, and trade is ex post efficient. These properties are shown to be preserved even when different distributions are differentially costly as long as the cost is monotone in the dispersion of the distribution.
参考文献：Daniele Condorelli and Balázs Szentes, "Information Design in the Holdup Problem," Journal of Political Economy 128, no. 2 (February 2020): 681-709.
https://www.journals.uchicago.edu/doi/full/10.1086/704574
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9. 物以类聚：同性和异性家庭中同性婚姻的结构比较
摘要：在本文中，我们将Gary Becker对婚姻市场的实证分析扩展到同性伴侣身上。我们建立了一个同性婚姻市场的均衡模型，该模型可以直接识别婚姻的收益。我们利用2008-12年美国加州的社区调查数据估计了该模型，结果发现在年龄和种族方面，同性伴侣的门当户对倾向比异性伴侣要弱。在教育方面，女性同性伴侣更倾向于门当户对，而男性同性伴侣和异性伴侣则差不多。在劳动力市场方面，我们的结果表明，家庭内部分工主要适用于不同性别的夫妇。
Abstract: In this paper, we extend Gary Becker’s empirical analysis of the marriage market to same-sex couples. We build an equilibrium model of the same-sex marriage market that allows for straightforward identification of the gains of marriage. We estimate the model with 2008–12 American Community Survey data on California and find that positive assortative mating is weaker for same-sex couples than for different-sex couples with respect to age and race. Positive assortative mating on education is stronger among female same-sex couples but comparable for male same-sex and different-sex couples. As regards labor market outcomes, our results suggest that specialization within the household mainly applies to different-sex couples.
参考文献：Edoardo Ciscato, Alfred Galichon, and Marion Goussé, "Like Attract Like? A Structural Comparison of Homogamy across Same-Sex and Different-Sex Households," Journal of Political Economy 128, no. 2 (February 2020): 740-781.
https://www.journals.uchicago.edu/doi/full/10.1086/704611
10. 论最优金融抑制
摘要：什么时候实施金融抑制（即使银行持有政府债务的政策）才是最优的? 有了承诺，这样的政策永远不会是最优的，因为这一政策挤出了银行的生产性投资。如果没有承诺，且当政府需要发行巨额债务时(比如战时)，金融抑制是最优选择。在这种情况下，金融抑制可以让政府可信地发行更多债务。金融抑制增加了可信度，因为当银行持有政府债务时，违约会稀释净值，减少投资，因此违约的事后成本高昂。迫使银行内生地持有债务，会增加事后成本，但也会产生事前成本，因为这样做会挤出投资。
Abstract: When is financial repression—namely, policies that force banks to hold government debt—optimal? With commitment, such policies are never optimal because they crowd out banks’ productive investments. Without commitment, they are optimal when governments need to issue unusually large amounts of debt, such as during wartime. In such times, repression allows governments to credibly issue more debt. Repression increases credibility because when banks hold government debt, defaults dilute net worth, reduce investment, and are thus costly ex post. Forcing banks to hold debt endogenously increases these ex post costs but has ex ante costs because doing so crowds out investments.
