American Economic Review

We explore how traders' equity capitalization influences asset prices in a framework that accounts for market power. In our model, traders with capital constraints engage in transactions in an imperfectly competitive market. We demonstrate that looser capital constraints elevate both asset prices and price impact, the latter diminishing market liquidity. Using Canadian Treasury auction data, we illustrate how to apply our model to quantify these effects. We estimate the shadow costs of capital constraints by leveraging a temporary policy exemption during 2020–2021. We show that while these constraints are only infrequently binding, their relative impact when activated can be sizable. (JEL E63, G12, G14, G23, G41, L13)

本文在一个考虑市场势力的框架中探讨交易者权益资本如何影响资产价格。在模型中，受资本约束的交易者在不完全竞争市场中进行交易。我们证明，放松资本约束会同时推高资产价格和价格冲击系数，后者会降低市场流动性。利用加拿大国债拍卖数据，我们展示了如何应用该模型来量化这些效应。借助2020-2021年间的一项临时政策豁免，我们估计了资本约束的影子成本。研究表明，尽管这些约束仅在少数情况下具有约束力，但一旦被激活，其相对影响可能相当可观。

We provide a model to explain how the interaction between the spot and lending markets for stocks can lead to abrupt changes in short selling activity. Furthermore, rational short sellers may choose to abandon the market even as mispricing widens. We document empirically that the dynamics of short selling are fat tailed and subject to abrupt changes, especially for the stocks that the model identifies as susceptible to such dynamics. (JEL G11, G12, G14, G41)

本文提出了一个模型来解释股票现货市场与融券市场之间的互动如何导致卖空活动的突变。此外，理性的卖空者即使在错误定价扩大时也可能选择退出市场。我们从实证上证明，卖空动态呈厚尾分布且容易发生突变，尤其对于模型识别为易受此类动态影响的股票而言更是如此。

Digitization reforms have been hailed as an effective way of strengthening state capacity. However, digitization can also fundamentally reshape the organization of bureaucracies. Using a unique administrative dataset on agricultural taxation and surveys of local bureaucrats from Punjab, Pakistan, we show that digitization reforms can have unintended consequences for state capacity. We exploit the staggered rollout of the digitization of land records in Punjab to show that digitization had a negative effect on tax collection. The fall in taxes was not due to a decrease in the tax base. Instead, digitization affected the bureaucrats' capacity to collect taxes. (JEL D73, H11, H71, O12, O17)

数字化改革被誉为加强国家能力的有效途径。然而，数字化也可能从根本上重塑官僚机构的组织方式。利用来自巴基斯坦旁遮普省农业税收的独特行政数据集和对地方官僚的调查，我们发现数字化改革可能对国家能力产生意想不到的后果。我们利用旁遮普省土地登记数字化的逐步推广来说明，数字化对税收征收产生了负面影响。税收下降并非由于税基减少，而是数字化影响了官僚征收税款的能力。

The validity of instrumental variable (IV) designs is typically tested using two types of falsification tests. We characterize these tests as conditional independence tests between negative control variables—proxies for unobserved variables posing a threat to the identification—and the IV or the outcome. We describe the conditions variables must satisfy in order to serve as negative controls. We show these falsification tests examine not only independence and the exclusion restriction but also functional form assumptions. Our analysis reveals conventional applications of these tests may flag problems even in valid IV designs. We offer implementation guidance to address these issues. (JEL C12, C18, C26, C52)

工具变量设计的有效性通常通过两类证伪检验来验证。本文将这两类检验刻画为阴性对照变量——即代表对识别构成威胁的未观测变量的代理变量——与工具变量或结果变量之间的条件独立性检验。我们描述了变量须满足的条件以充当阴性对照。我们证明，这些证伪检验不仅检验独立性和排他性约束，还检验了函数形式假设。我们的分析揭示，这些检验的传统应用方式甚至可能在有效的工具变量设计中也标记出问题。我们提供了解决这些问题的实施指南。

We study a canonical collective action game with incomplete information. Individuals attempt to coordinate to achieve a shared goal, while also facing a temptation to free-ride. More similar information can help them coordinate, but it can also exacerbate free-riding. Our main result shows that more similar information facilitates (impedes) achieving the common goal when it is sufficiently challenging (easy). We apply this insight to show why less powerful authoritarian governments may face larger protests if they restrict press freedom, when committee diversity is beneficial in costly voting, and when a more diverse community contributes more to public good provision. (JEL C71, D71, D72, D81, D82, D83, H41)

本文研究了一个不完全信息下的经典集体行动博弈。个体试图协调以实现共同目标，同时面临搭便车的诱惑。更相似的信息有助于他们协调，但也可能加剧搭便车行为。我们的主要结果表明，当共同目标足够困难时，更相似的信息会促进目标实现；而当目标足够容易时，更相似的信息反而阻碍目标实现。我们应用这一洞见来解释：为什么较弱的威权政府限制新闻自由可能面临更大规模的抗议；在成本高昂的投票中，委员会多元化何时有益；以及更异质的社区何时对公共品供给贡献更多。

Why do health facilities in developing countries do so poorly? This paper examines the role of financial constraints. I describe an experiment in which we surprised health workers in randomly selected public health clinics in Nigeria with a ₦600,000 grant paid out in installments over one year. Its administration was left entirely to health workers. The award led to large productivity gains. Using expenditure data combined with novel textual data, I provide an explanation for these effects. I show the award increased investments in physical and human capital, led to lower prices for patients, and inspired health workers to do better. (JEL D24, G31, H75, I11, J24, J31, O15)

为什么发展中国家的医疗设施表现如此糟糕？本文考察了财务约束的作用。我描述了一项实验：我们在尼日利亚随机选择的公立卫生诊所中，以一年内分期发放的方式给卫生工作者提供了一笔60万奈拉的意外拨款，拨款的使用完全由卫生工作者自主管理。这笔拨款带来了大幅生产率提升。结合支出数据和新型文本数据，我为这些效果提供了解释。研究表明，拨款增加了对物质资本和人力资本的投资，降低了患者支付的价格，并激励卫生工作者做得更好。

We study how international migrant income prospects affect long-run development in origin areas. We leverage the 1997 Asian Financial Crisis exchange rate shocks in a shift-share identification strategy across Philippine provinces. Initial migrant income shocks are magnified six-fold over time, increasing domestic income, education levels, migrant skills, and high-skilled migration. Remarkably, 74.9 percent of long-run income gains come from domestic rather than migrant income. Trade driven impacts of exchange rate shocks are orthogonal to effects via migrant income. A structural model reveals that 19.7 percent of long-run income gains stem from educational investments. International migration fosters broad economic development in origin communities. (JEL F22, F31, G01, J24, J82, O15, O16)

本文研究国际移民收入前景如何影响来源地的长期发展。我们利用1997年亚洲金融危机中的汇率冲击，在菲律宾各省之间采用移位-份额识别策略。初始移民收入冲击随时间推移被放大六倍，提高了国内收入、教育水平、移民技能和高技能移民比例。值得注意的是，长期收入增长的74.9%来自国内收入而非移民收入。汇率冲击经由贸易渠道的影响与经由移民收入的影响相互正交。结构模型揭示，长期收入增长的19.7%源于教育投资。国际移民促进了来源社区的广泛经济发展。

We develop a simple multilayer network model in which agents allocate effort across layers with heterogeneous structures, subject to an aggregate effort constraint. Incentives are shaped by agents' network positions within each layer, and equilibrium behavior reflects both within- and cross-layer interactions. We analyze how shocks propagate through the network and characterize optimal targeting interventions. Our results show that effective policy design must account for effort allocation across layers. We also demonstrate that predictions from monolayer models can diverge sharply from those of multilayer models, underscoring the importance of accounting for network complexity in both empirical and policy analyses. (JEL C70, D78, D82, D85, H41, Z13)

本文构建了一个简单的多层网络模型，其中行动者在结构异质的各层之间分配努力，并受总努力约束。激励由行动者在每层中的网络位置所塑造，均衡行为反映了层内和跨层互动。我们分析了冲击如何通过网络传播，并刻画了最优定向干预的特征。我们的结果表明，有效的政策设计必须考虑跨层的努力分配。我们还证明，单层模型的预测可能与多层模型的预测存在显著差异，这凸显了在实证和政策分析中考虑网络复杂性的重要性。

This paper studies which misspecified models are likely to persist when decision-makers compare them with competing models. The main result characterizes such models based on two features that can be derived from primitives: The model's asymptotic accuracy in predicting the equilibrium distribution of observed outcomes and the "tightness" of the prior around such equilibria. Misspecified models can be robust, persisting against any arbitrary competing model—including the true model—despite decision-makers observing an infinite amount of data. Moreover, simple misspecified models equipped with entrenched priors can be more robust than complex correctly specified models. (JEL C11, C52, D11, L82)

本文研究当决策者将错误设定模型与竞争模型进行比较时，哪些错误设定模型可能持续存在。主要结果基于可从原始条件导出的两个特征来刻画此类模型：模型在预测观测结果的均衡分布方面的渐近准确性，以及围绕此类均衡的先验分布的"紧密度"。错误设定模型可以是稳健的，能够在面对任何任意竞争模型（包括真实模型）时持续存在，即使决策者观察到无限量的数据也是如此。此外，配备了根深蒂固先验的简单错误设定模型可能比复杂的正确设定模型更加稳健。

We embed diagnostic expectations in a workhorse neoclassical model with heterogeneous firms and risky debt. A realistic degree of overreaction estimated from US firms' earnings forecasts generates realistic credit cycles. Good times produce economic and financial fragility, predicting future disappointment of expectations, low bond returns, and investment declines. To generate the size of spread increases observed during 2007–2009, the model requires only moderate negative shocks. Diagnostic expectations offer a realistic, parsimonious way to produce financial reversals in business cycle models. (JEL D84, E13, E22, E32, E44, G12, G32)

本文将诊断性预期嵌入一个包含异质性企业和风险债务的标准新古典模型。从美国企业盈利预测中估计的现实过度反应程度产生了真实的信贷周期。繁荣时期造就经济和金融脆弱性，预示着未来的预期落空、低债券回报和投资下降。为了产生2007-2009年间观察到的利差扩大幅度，模型仅需适度的负面冲击。诊断性预期为在商业周期模型中产生金融逆转提供了一种现实且简约的方式。