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解析文章首发于唧唧堂网站www.jijitang.com
解析作者 | 唧唧堂经济学小组：
战战
；审校编辑 |
悠悠
1. 歧视的动态性：理论与证据
我们建立了歧视的动态模型，并且表明，歧视的动态演进可以使我们识别出歧视的潜在来源。在一个大型在线平台的田野实验（field experiment）中，我们检验了这些理论预测，在这个大型在线平台上，用户发布的内容会被平台上的其他用户所评论。我们将用户发布的内容按照用户性别和评论历史分类之后，分发给平台上的其他用户来评论。在不考虑评论历史的情况下，女性用户面临着严重的歧视。然而，在一系列的正面评论之后，歧视的方向发生了逆转：女性用户发布的内容比男性用户发布的内容更受青睐。运用我们的模型来解释这些结果，这种动态逆转意味着歧视是由有偏见的信念所引起的。
We model the dynamics of discrimination and show how its evolution can identify the underlying source. We test these theoretical predictions in a field experiment on a large online platform where users post content that is evaluated by other users on the platform. We assign posts to accounts that exogenously vary by gender and evaluation histories. With no prior evaluations, women face significant discrimination. However, following a sequence of positive evaluations, the direction of discrimination reverses: women's posts are favored over men's. Interpreting these results through the lens of our model, this dynamic reversal implies discrimination driven by biased beliefs.
参考文献：Bohren, J. Aislinn, Alex Imas, and Michael Rosenberg. 2019. "The Dynamics of Discrimination: Theory and Evidence." American Economic Review, 109 (10): 3395-3436.
DOI: 10.1257/aer.20171829
2. 或然性推理的失败：不确定性的作用
我们提出了一种新的方式来解释为什么个体在或然性推理（contingent reasoning）中会面临困难：不确定性的存在。从一个已知值状态到多个可能值状态，发生了两个变化。第一，要考虑的值的数量增加了。第二，状态的值变成了不确定的。我们通过实验表明，这种确定性的缺乏，或确定性控制力的丧失，会阻碍收益最大化，这解释了或然性推理之所以困难的大部分原因。
We propose a new channel to account for the difficulties of individuals with contingent reasoning: the presence of uncertainty. When moving from an environment with one state of known value to one with multiple possible values, two changes occur. First, the number of values to consider increases. Second, the value of the state is uncertain. We show in an experiment that this lack of certainty, or the loss of the Power of Certainty, impedes payoff maximization and that it accounts for a substantial portion of the difficulties with contingent reasoning.
参考文献：Martínez-Marquina, Alejandro, Muriel Niederle, and Emanuel Vespa. 2019. "Failures in Contingent Reasoning: The Role of Uncertainty." American Economic Review, 109 (10): 3437-74.
DOI: 10.1257/aer.20171764
3. 企业补贴的均衡效应
补贴计划对企业有两种相抵消的效果：为符合补贴条件的企业带来了直接收益，为竞争对手符合补贴条件的企业带来了间接损失。2006年，印度改变了小企业获得补贴的资格标准，新取得补贴资格的那些企业，它们的销售额增长了大约35%。而这些企业的竞争对手也受到了影响，国际贸易较少的产品几乎被彻底挤出了市场，但国际贸易较多的产品并没有被挤出市场。新取得补贴资格的那些企业，拥有相对较高的边际产量，因此放宽补贴资格标准可以使总生产率提高大约1到2个百分点。假如把补贴目标换成别的企业，可能也会导致类似的总生产率提高。
Subsidy programs have two countervailing effects on firms: direct gains for eligible firms and indirect losses for those whose competitors are eligible. In 2006, India changed the eligibility criteria for small-firm subsidies, and the sales of newly eligible firms grew by roughly 35 percent. Competitors of the newly eligible firms were affected, with almost complete crowd-out within products that were less internationally traded, but little crowd-out for more-traded products. The newly eligible firms had relatively high marginal products, so relaxing the eligibility criteria for subsidies increased aggregate productivity by around 1−2 percent. Targeting different firms could have led to similar gains.
参考文献：Rotemberg, Martin. 2019. "Equilibrium Effects of Firm Subsidies." American Economic Review, 109 (10): 3475-3513.
DOI: 10.1257/aer.20171840
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4.信用评级市场中的竞争和战略激励：2007年金融危机的实证分析
我们研究了从21世纪初至2007-2008年那场金融危机结束（本文认为持续到2012年）这段期间，商业抵押担保证券（Commercial Mortgage Backed Securities，CMBS）部门中的评级机构市场。利用从拍卖文献中改编而来的结构模型，我们把评级机构向有利于发行人的方向扭曲评级结果的动机，进行了数理化表征。我们的重要发现是均衡扭曲，而且在2007年金融危机之后扭曲减少了。最后，我们还研究了与业内近期政策制定有关的几个反事实实验。
We study the market for ratings agencies in the commercial mortgage backed securities sector leading up to and including the financial crisis of 2007–2008. Using a structural model adapted from the auctions literature, we characterize the incentives of ratings agencies to distort ratings in favor of issuers. We find an important equilibrium distortion, which decreased after the crisis. We study several counterfactual experiments motivated by recent policymaking in this industry.
参考文献：Chu, Chenghuan Sean, and Marc Rysman. 2019. "Competition and Strategic Incentives in the Market for Credit Ratings: Empirics of the Financial Crisis of 2007." American Economic Review, 109 (10): 3514-55.
DOI: 10.1257/aer.20140773
5. 通胀违约吗？信息在债务危机中的作用
我们研究了以本币计价的政府债务和以外币计价的政府债务的信息敏感度：以本币计价的政府债务具有通货膨胀风险，以外币计价的政府债务具有违约风险。违约只会影响高级债券交易员，而通胀则关系到更大规模的、并没有那么见多识广的群体。在两阶段贝叶斯交易博弈中，信息差异体现在二级市场上，而即使在只有高级参与者操作的一级市场上，我们也表明了在什么样的条件下债务价格对坏消息的弹性会更强。我们的结果不仅可以解释2008年金融危机之后各国的债务价格，而且还提供了一个“原罪”理论。
We study the information sensitivity of government debt denominated in domestic versus foreign currency: the former is subject to inflation risk and the latter to default. Default only affects sophisticated bond traders, whereas inflation concerns a larger and less informed group. Within a two-period Bayesian trading game, differential information manifests itself in the secondary market, and we display conditions under which debt prices are more resilient to bad news even in the primary market, where only sophisticated players operate. Our results can explain debt prices across countries following the 2008 financial crisis, and also provide a theory of "original sin."
参考文献：Bassetto, Marco, and Carlo Galli. 2019. "Is Inflation Default? The Role of Information in Debt Crises." American Economic Review, 109 (10): 3556-84.
DOI: 10.1257/aer.20170721
6. 农村劳动力市场的名义工资刚性
降雨量是对劳动力需求的短暂冲击，通过对印度600个地区降雨量的考察，本文提出了一种检验工资下降刚性（downward wage rigidity）的新方法。名义工资在劳动力需求受到正向冲击时会上升，但在干旱时并不会下降。此外，短暂的正向冲击会产生棘轮效应：当冲击消失后，名义工资不会回降。棘轮效应使就业率下降了9%，说明工资刚性扭曲了就业水平。由于通货膨胀并不受当地降雨量的影响，因此实际工资很可能会下降，这为劳动力市场效应提供了因果证据。调查显示，个体认为削减名义工资是不公平的，这会导致个体减少努力。
This paper develops a new approach to test for downward wage rigidity by examining transitory shocks to labor demand (i.e., rainfall) across 600 Indian districts. Nominal wages rise during positive shocks but do not fall during droughts. In addition, transitory positive shocks generate ratcheting: after they have dissipated, wages do not adjust back down. Ratcheting reduces employment by 9 percent, indicating that rigidities distort employment levels. Inflation, which is unaffected by local rainfall, enables downward real wage adjustments—offering causal evidence for its labor market effects. Surveys suggest that individuals believe nominal wage cuts are unfair and lead to effort reductions.
参考文献：Kaur, Supreet. 2019. "Nominal Wage Rigidity in Village Labor Markets." American Economic Review, 109 (10): 3585-3616.
DOI: 10.1257/aer.20141625
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7.企业的内部网络与地方经济冲击
利用美国人口普查局纵向商业数据库(LBD)中的机构级数据，本文研究了地方冲击是如何通过企业内部机构网络而传递到美国各地的。与企业内最优资源配置模型相一致，我们发现，如果一个机构的母公司运营在偏远地区，那么这个机构的就业会对偏远地区的经济冲击非常敏感，并且冲击弹性会随着企业融资约束（financial constraint）的增加而增加。在区域层面上，我们发现，县级就业会对由企业内部网络所连接的偏远县的冲击非常敏感。
Using confidential establishment-level data from the US Census Bureau's Longitudinal Business Database, this paper documents how local shocks propagate across US regions through firms' internal networks of establishments. Consistent with a model of optimal within-firm resource allocation, we find that establishment-level employment is sensitive to shocks in distant regions in which the establishment's parent firm is operating, and that the elasticity with respect to such shocks increases with the firm's financial constraint. At the aggregate regional level, we find that aggregate county-level employment is sensitive to shocks in distant counties linked through firms' internal networks.
参考文献：Giroud, Xavier, and Holger M. Mueller. 2019. "Firms' Internal Networks and Local Economic Shocks." American Economic Review, 109 (10): 3617-49.
DOI: 10.1257/aer.20170346
8.信息和不确定性的量化
我们研究了如何测量由一条消息所产生的信息数量，以及如何测量隐含在给定信念（given belief）中的不确定性的数量。对信息的测量是有效的，如果它与决策问题中消息的价值相一致。对不确定性的测量是有效的，如果它与决策问题中由于状态不明而导致的预期效用损失相一致。我们给出了信息和不确定性有效测量的公理化定义。我们证明，在同一个决策问题中，信息和不确定性的测量是耦合的，因为预期的不确定性减少量总是等于预期的信息生成量。我们提出了信息测量的显式公式，信息测量与任何给定的不确定性测量相耦合，反之亦然。最后，我们还证明了，当且仅当支付函数是对信息的有效测量时，卖方才不会有动机去搞“延迟信息披露（delay information revelation）”。
We examine ways to measure the amount of information generated by a piece of news and the amount of uncertainty implicit in a given belief. Say a measure of information is valid if it corresponds to the value of news in some decision problem. Say a measure of uncertainty is valid if it corresponds to expected utility loss from not knowing the state in some decision problem. We axiomatically characterize all valid measures of information and uncertainty. We show that if measures of information and uncertainty arise from the same decision problem, then they are coupled in that the expected reduction in uncertainty always equals the expected amount of information generated. We provide explicit formulas for the measure of information that is coupled with any given measure of uncertainty and vice versa. Finally, we show that valid measures of information are the only payment schemes that never provide incentives to delay information revelation.
参考文献：Frankel, Alexander, and Emir Kamenica. 2019. "Quantifying Information and Uncertainty." American Economic Review, 109 (10): 3650-80.
DOI: 10.1257/aer.20181897
9. 监管权限影响投资顾问监管质量吗？
多德弗兰克法案（Dodd-Frank Act）把对“中型”投资顾问的监管权限从美国证券交易委员会（SEC）转移到了州级证券监管机构。与继续接受美国证券交易委员会（SEC）监管的投资顾问相比，客户对中型顾问的投诉率增加了30%至40%。投诉越来越多地提到了信托违规，并且在资源较少的州级监管机构中，投诉增加得更多。对较弱监管做出了更多回应的顾问曾经抱怨说，他们的位置离监管机构较远，面临的竞争较少，利益冲突较多，服务的都是些不太成熟的客户。如何实现对信息不对称（informational asymmetries）市场和有寻找摩擦（search frictions）市场的最优监管？我们的结果对此提供了启示。
The Dodd-Frank Act shifted regulatory jurisdiction over "midsize" investment advisers from the SEC to state-securities regulators. Client complaints against midsize advisers increased relative to those continuing under SEC oversight by 30 to 40 percent of the unconditional probability. Complaints increasingly cited fiduciary violations and rose more where state regulators had fewer resources. Advisers responding more to weaker oversight had past complaints, were located farther from regulators, faced less competition, had more conflicts of interest, and served primarily less-sophisticated clients. Our results inform optimal regulatory design in markets with informational asymmetries and search frictions.
参考文献：Charoenwong, Ben, Alan Kwan, and Tarik Umar. 2019. "Does Regulatory Jurisdiction Affect the Quality of Investment-Adviser Regulation?" American Economic Review, 109 (10): 3681-3712.
DOI: 10.1257/aer.20180412
