编者按：美国全国经济研究所（NBER）是美国最大的经济学研究组织，其发布的工作论文代表着经济学研究最新的成果，每周一发布新论文。本周（10.21-10.27）共发布 14 篇新工作论文，本期将会推送前 7 篇论文的题目与摘要，供读者学习。
学术财经研究团队翻译。
收入驱动还款计划如何使学生债务借款人受益？
Sylvain Catherine, Mehran Ebrahimian, and Constantine Yannelis #33059
Abstract: The rapid rise in student loan balances has raised concerns among economists and policymakers. Using administrative credit bureau data, we find that nearly half of the increase in balances from 2010 to 2020 is due to deferred payments, largely driven by the expansion of income-driven repayment (IDR) plans, which link payments to income. These plans help borrowers by smoothing consumption, insuring against labor income risk, and reducing the present value of future payments. We build a life-cycle model to quantify the welfare gains from this payment deferment and the channels through which borrower welfare increases. New, more generous IDR rules increase this transfers from taxpayers to borrowers without yielding net welfare gains. By lowering the average marginal cost of undergraduate debt to less than 50 cents per dollar, these rules may also incentivize excessive borrowing. We demonstrate that an optimally calibrated IDR plan can achieve similar welfare gains for borrowers at a much lower cost to taxpayers, and without encouraging additional borrowing, primarily through maturity extension.
摘要：学生贷款余额的快速增长引起了经济学家和政策制定者的关注。通过使用行政信用局数据，我们发现从2010年到2020年，贷款余额增长中近一半是由于延期还款，而这在很大程度上是由收入驱动还款（IDR）计划的扩展推动的。该计划将还款与收入挂钩，通过平滑消费、对劳动收入风险进行保险以及减少未来付款的现值来帮助借款人。我们建立了一个生命周期模型来量化这种延期还款带来的福利增益，以及借款人福利提高的渠道。新的、更慷慨的IDR规则增加了从纳税人到借款人的转移支付，但并未带来净福利增益。通过将本科学债务的平均边际成本降低到每美元不到50美分，这些规则可能还会激励过度借贷。我们证明，经过最优校准的IDR计划可以在降低纳税人成本的情况下，实现类似的借款人福利增益，并且不会鼓励额外借款，主要是通过延长还款期限实现的。
你的生命时光：加拿大人的死亡率与寿命
Kevin S. Milligan #33066
Abstract: I develop and implement a methodology for cohort life expectancy using a panel of administrative tax data on a large sample born between 1930 and 1964. Over these 35 years, cohort life expectancy after age 54 grew by 5 years for women and 7 years for men. The income-longevity gradient for the top vs. bottom five percent of incomes is 9 years of post-54 life for men and 7 years for women. The life expectancy improvements arise across the income distribution in Canada, unlike the United States. Large differences across neighbourhoods emerge which cannot be explained by income differences alone.
摘要：我开发并实施了一种基于大量1930年至1964年出生样本的行政税务数据面板的队列预期寿命方法。在这35年间，54岁之后的队列预期寿命对于女性增长了5年，对于男性增长了7年。收入与寿命的梯度在最高收入的前5%与最低收入的后5%之间，男性的54岁后寿命差距为9年，女性为7年。在加拿大，寿命预期的改善遍及整个收入分布，与美国不同。此外，出现了各社区之间的大幅差异，而这种差异不能仅通过收入差异来解释。
宏观经济危机的劳动力市场解析
Kevin Donovan, Will Jianyu Lu, Joseph H. Pedtke, and Todd Schoellman #33061
Abstract: This paper uses two large datasets built from quarterly labor force surveys to provide a global perspective on labor market downturns. The distribution of the severity and duration of labor market downturns is strongly right skewed. The longest and most severe downturns are associated with crises, particularly financial crises, sudden stops, and house price busts. Manufacturing and construction are key sectors for propagation, as they account for more than half of the total decline in employment. Labor market downturns fall most on young and less-educated workers, who are less able to self-insure against idiosyncratic earnings risk.
摘要：本文使用了基于季度劳动力调查的两个大型数据集，提供了全球视角下的劳动力市场衰退分析。劳动力市场衰退的严重程度和持续时间分布呈明显的右偏分布。最严重且持续时间最长的衰退与危机相关，尤其是金融危机、突然的资金流停止以及房价暴跌。制造业和建筑业是衰退传播的关键部门，它们占就业总下降的50%以上。劳动力市场衰退对年轻和受教育程度较低的工人影响最大，因为他们较难通过自身手段应对个体化收入风险。
选举人票、总统支持率与消费者信心如何回应经济指标？
Robert J. Gordon #33068
Abstract: This paper studies the effect of economic indicators on the Michigan Consumer Sentiment Index, Presidential approval ratings, and Presidential election outcomes since 1956. How closely do the indicators predict sentiment, how well does sentiment predict approval, and what role does approval have in explaining election outcomes measured by electoral votes? How much of the variance of approval ratings depends on non-economic factors like the “honeymoon effect”? Is there a role for economic indicators in explaining election outcomes once the contribution of approval ratings is taken into account? Regression equations provide answers to these questions and allow new interpretations of political history. Equation residuals and the contributions of specific variables are graphically displayed, providing insights into time intervals when sentiment was above or below the prediction of economic indicators, when approval differed from its usual relation with sentiment and the indicators, and when and why the electoral vote totals in each election since 1956 exceeded or fell short of the predictions of the econometric equations.
摘要：本文研究了自1956年以来经济指标对密歇根消费者信心指数、总统支持率以及总统选举结果的影响。经济指标与消费者信心的预测能力有多大？消费者信心对总统支持率的预测效果如何？总统支持率在解释以选举人票衡量的选举结果中起到了什么作用？总统支持率的波动中有多少取决于非经济因素，如“蜜月期效应”？在考虑到总统支持率的贡献后，经济指标在解释选举结果时还有多大作用？回归方程为这些问题提供了答案，并允许对政治历史作出新的解释。方程残差和特定变量的贡献通过图形展示，揭示了消费者信心高于或低于经济指标预测的时间段，总统支持率偏离其与信心及经济指标通常关系的时期，以及自1956年以来每次选举中的选举人票总数为何会超出或低于经济模型的预测。
具有交易成本的最优动态资产配置：对冲需求的作用
Pierre Collin-Dufresne, Kent D. Daniel, and Mehmet Sağlam #33058
Abstract: A number of papers have solved for the optimal dynamic portfolio strategy when expected returns are time-varying and trading is costly, but only for agents with myopic utility. Non-myopic agents benefit from hedging against future shocks to the investment opportunity set even when transaction costs are zero (Merton, 1969, 1971). In this paper, we propose a solution to the dynamic portfolio allocation problem for non-myopic agents faced with a stochastic investment opportunity set when trading is costly. We show that the agent’s optimal policy is to trade toward an “aim” portfolio, the makeup of which depends both on transaction costs and on each asset’s correlation with changes in the investment opportunity set. The speed at which the agent should trade towards the aim portfolio depends both on the shock’s persistence and on the extent to which the shock can be effectively hedged. We illustrate the differences in portfolio makeup that result from considering hedging demands of a long-horizon investor using a set of simplified examples, and using a daily trading strategy based on the estimated relation between retail order imbalance and future returns.
摘要：许多论文已经解决了在预期收益率随时间变化且交易成本较高的情况下的最优动态投资组合策略，但这些研究仅针对具有短视效用的代理人。非短视代理人，即使在交易成本为零的情况下，也能通过对未来投资机会集的冲击进行对冲而受益（Merton, 1969, 1971）。本文提出了一种解决方案，针对面临随机投资机会集且交易成本较高的非短视代理人，解决其动态投资组合分配问题。我们展示了代理人的最优策略是朝着一个“目标”投资组合进行交易，这个组合的构成取决于交易成本以及每种资产与投资机会集变化的相关性。代理人应该以多快的速度向目标投资组合进行交易，取决于冲击的持续性以及冲击能被有效对冲的程度。我们通过一系列简化示例说明了考虑长期投资者对冲需求时，投资组合构成的差异，并基于零售订单失衡与未来收益之间的估计关系，使用日常交易策略进行了说明。
物理学中新颖论文的产生与影响
Jacques Mairesse, Michele Pezzoni, and Frederique Sachwald #33064
Abstract: The aim of this paper is twofold. First, it investigates how the characteristics of a research team relate to the probability of generating a novel article. Second, once a novel article has been generated, it investigates the moderating effects of the team's characteristics on the impact of the article. We consider 42,493 teams of researchers publishing a corresponding number of articles in 273 reputed journals in physics from 2005 to 2009. We find that team experience and team specialization are negatively associated with the probability of generating a novel article. On the contrary, having already written novel articles in the past is positively associated with the probability of generating a novel article. When analyzing the impact of novel articles, we find that a novel article published by an experienced team receives fewer citations than a novel article published by a team with less experience and is published in a lower impact factor journal. We also find that a novel article published by a large established team of researchers receives more citations than a novel article published by a small newly formed team. The team size is also positively related to the impact factor of the journal in which the novel article is published.
摘要：本文的目标有两个。首先，它探讨了研究团队的特征如何与生成创新性论文的概率相关。其次，当创新性论文产生后，研究团队特征对论文影响力的调节作用如何。我们分析了42,493个研究团队，他们在2005年至2009年间在273本著名物理学期刊上发表了相应数量的文章。研究发现，团队经验和团队专业化与生成创新性论文的概率呈负相关。相反，过去已经撰写过创新性论文的团队更有可能再次生成创新性论文。在分析创新性论文的影响力时，我们发现，经验丰富的团队发表的创新性论文比经验较少团队发表的创新性论文收到的引用更少，且发表在影响因子较低的期刊上。此外，我们还发现，由大型资深研究团队发表的创新性论文获得的引用更多，而由小型新组建团队发表的创新性论文引用较少。团队规模也与创新性论文发表期刊的影响因子呈正相关。
科学中的不平等：谁成为明星？
Anna Airoldi and Petra Moser #33063
Abstract: How does a person’s childhood socioeconomic status (SES) influence their chances to participate and succeed in science? To investigate this question, we use machine-learning methods to link scientists in a comprehensive biographical dictionary, the American Men of Science (1921), with their childhood home in the US Census and with publications. First, we show that children from low-SES homes were already severely underrepresented in the early 1900s. Second, we find that SES influences peer recognition, even conditional on participation: Scientists from high-SES families have 38% higher odds of becoming stars, controlling for age, publications, and disciplines. Using live-in servants as an alternative measure for SES confirms the strong link between childhood SES and becoming a star. Applying text analysis to assign scientists to disciplines, we find that mathematics is the only discipline in which SES influences stardom through the number and the quality of a scientist’s publications. Using detailed data on job titles to distinguish academic from industry scientists, we find that industry scientists have lower odds of being stars. Controlling for industry employment further strengthens the link between childhood SES and stardom. Elite undergraduate degrees explain more of the correlation between SES and stardom than any other control. At the same time, controls for birth order, family size, foreign-born parents, maternal education, patents, and connections with existing stars leave estimates unchanged, highlighting the importance of SES.
摘要：一个人的童年社会经济地位（SES）如何影响他们参与科学和在科学领域取得成功的机会？为研究这个问题，我们使用机器学习方法，将《美国科学名人录》（1921年版）中的科学家与他们在美国人口普查中的童年家庭信息以及其出版物相联系。首先，我们发现，低SES家庭的孩子在20世纪初就已经严重代表不足。其次，即使参与科学领域，SES仍会影响同行的认可度：来自高SES家庭的科学家成为明星的几率高出38%，即使控制了年龄、出版物和学科。使用是否雇佣住家佣人作为SES的替代衡量指标，进一步证实了童年SES与成为明星之间的紧密联系。通过文本分析将科学家分配到不同学科，我们发现数学是唯一一个SES通过科学家的出版数量和质量影响其成为明星的学科。利用详细的职位数据区分学术科学家和工业科学家，我们发现工业科学家成为明星的几率较低。控制工业就业后，童年SES与成为明星的关联进一步加强。精英本科学位比其他任何控制因素都更能解释SES与成为明星的相关性。同时，控制出生顺序、家庭规模、父母是否为外国出生、母亲的教育水平、专利以及与现有明星的关系等因素后，估计结果未发生变化，进一步强调了SES的重要性。
往期精选：
