云计算和人工智能对行业动态和集中度的影响

Yao Lu, Gordon M. Phillips, and Jia Yang #32811

Abstract: We examine the rise of cloud computing and AI in China and their impacts on industry dynamics after the shock to the cost of Internet-based computing power and services. We find that cloud computing is associated with an increase in firm entry, exit and the likelihood of M&A in industries that depend more on cloud infrastructure. Conversely, AI adoption has no impact on entry but reduces the likelihood of exit and M&A. Firm size plays a crucial role in these dynamics: cloud computing increases exit rates across all firms, while larger firms benefit from AI, experiencing reduced exit rates. Cloud computing decreases industry concentration but AI increases concentration. On the financing side, firms exposed to cloud computing increase equity and venture capital financing, while only large firms increase equity financing when exposed to AI.

摘要：我们研究了云计算和人工智能在中国的兴起，以及在互联网计算能力和服务成本发生冲击后，它们对行业动态的影响。我们发现，在更依赖云基础设施的行业中，云计算与企业进入、退出以及并购可能性的增加相关。相反，人工智能的采用对企业进入没有影响，但减少了退出和并购的可能性。企业规模在这些动态中起着关键作用：云计算提高了所有企业的退出率，而大型企业则从人工智能中受益，退出率有所降低。云计算降低了行业集中度，但人工智能提高了行业集中度。在融资方面，暴露于云计算的企业增加了股权和风险投资融资，而暴露于人工智能的只有大型企业增加了股权融资。

学术科学中团队合作的兴起与职业前景

Mabel Andalón, Catherine de Fontenay, Donna K. Ginther, and Kwanghui Lim #32827

Abstract: Teamwork has become more important in recent decades. We show that larger teams generate an unintended side effect: individuals who finish their PhD when the average team in their field is larger have worse career prospects. Our analysis combines data on career outcomes from the Survey of Doctorate Recipients with publication data that measures team size from ISI Web of Science. As average team size in a field increased over time, junior academic scientists became less likely to secure research funding or obtain tenure and were more likely to leave academia relative to their older counterparts. The team size effect can fully account for the observed decline in tenure prospects in academic science. The rise in team size was not associated with the end of mandatory retirement. However, the doubling of the NIH budget was associated with a significant increase in team size. Our results demonstrate that academic science has not adjusted its reward structure, which is largely individual, in response to team science. Failing to address these concerns means a significant loss as junior scientists exit after a costly and specialized education in science.

摘要：团队合作在最近几十年变得越来越重要。我们发现，较大的团队产生了一个意外的副作用：在团队平均规模较大的领域获得博士学位的个人，其职业前景较差。我们的分析结合了《博士学位获得者调查》的职业结果数据和《ISI Web of Science》中的团队规模出版数据。随着某一领域的平均团队规模随时间增加，相比年长的同行，年轻的学术科学家获得研究资金或终身教职的机会减少，离开学术界的可能性增加。团队规模效应可以完全解释学术科学中终身教职前景下降的现象。团队规模的增长与强制退休制度的结束无关，但与美国国立卫生研究院（NIH）预算翻倍有显著关联。我们的研究结果表明，学术科学尚未对团队科学的发展做出调整，依然主要基于个人的奖励结构。如果不解决这些问题，将导致年轻科学家在经过高成本的专业化教育后退出，造成巨大的损失。

外貌与游戏：谁在参与，为什么？

Andy Chung, Daniel S. Hamermesh, Carl Singleton, Zhengxin Wang, and Junsen Zhang #32809

Abstract: We investigate the relationship between physical attractiveness and the time people devote to video/computer gaming. Average American teenagers spend 2.6% of their waking hours gaming, while for adults this figure is 2.7%. Using the American Add Health Study, we show that adults who are better-looking have more close friends. Arguably, gaming is costlier for them, and they thus engage in less of it. Physically attractive teens are less likely to engage in gaming at all, whereas unattractive teens who do game spend more time each week on it than other gamers. Attractive adults are also less likely than others to spend any time gaming; and if they do, they spend less time on it than less attractive adults. Using the longitudinal nature of the Add Health Study, we find supportive evidence that these relationships are causal for adults: good looks decrease gaming time, not vice-versa.

摘要：我们研究了身体吸引力与人们在视频/电脑游戏上花费时间之间的关系。数据显示，平均而言，美国青少年在清醒时间的2.6%用来玩游戏，而成年人则为2.7%。通过分析美国Add Health研究数据，我们发现身体吸引力更强的成年人有更多的亲密朋友。可以认为，游戏对他们来说成本更高，因此他们参与的游戏活动较少。身体吸引力较强的青少年不太可能参与游戏，而不具吸引力的青少年如果玩游戏，他们每周花费的时间比其他玩家更多。吸引力较强的成年人也不太可能花时间在游戏上；即使他们玩游戏，所花时间也比吸引力较弱的成年人少。通过利用Add Health研究的纵向数据，我们发现有力的证据支持这一结论对成年人来说是因果关系：外貌出众会减少游戏时间，而不是相反。

健康不平等与健康类型

Margherita Borella, Francisco A. Bullano, Mariacristina De Nardi, Benjamin Krueger, and Elena Manresa #32799

Abstract: While health affects many economic outcomes, its dynamics are still poorly understood. We use k means clustering, a machine learning technique, and data from the Health and Retirement Study to identify health types during middle and old age. We identify five health types: the vigorous resilient, the fair-health resilient, the fair-health vulnerable, the frail resilient, and the frail vulnerable. They are characterized by different starting health and health and mortality trajectories. Our five health types account for 84% of the variation in health trajectories and are not explained by observable characteristics, such as age, marital status, education, gender, race, health-related behaviors, and health insurance status, but rather, by one’s past health dynamics. We also show that health types are important drivers of health and mortality heterogeneity and dynamics. Our results underscore the importance of better understanding health type formation and of modeling it appropriately to properly evaluate the effects of health on people’s decisions and the implications of policy reforms.

摘要：虽然健康影响许多经济结果，但其动态仍然理解不足。我们使用K均值聚类（一种机器学习技术）和健康与退休研究（Health and Retirement Study）的数据，来识别中年和老年阶段的健康类型。我们确定了五种健康类型：充满活力的有韧性者、健康状况一般的有韧性者、健康状况一般的脆弱者、虚弱的有韧性者和虚弱的脆弱者。它们在起始健康状况、健康和死亡率轨迹上表现出不同的特征。我们的五种健康类型解释了84%的健康轨迹差异，并且这些类型并不由年龄、婚姻状况、教育程度、性别、种族、健康相关行为和健康保险状况等可观测特征所解释，而是由个人过去的健康动态所决定的。我们还表明，健康类型是健康和死亡率异质性和动态的重要驱动因素。我们的研究结果强调了更好地理解健康类型形成的重要性，以及适当建模以正确评估健康对人们决策的影响和政策改革的意义。

测量将2024年种族和民族标准引入当前人口调查的潜在影响

Mark Loewenstein, David Piccone, and Anne Polivka #32812

Abstract: When obtaining information on individuals’ race and ethnicity, the Current Population Survey (CPS) currently follows the 1997 OMB standards, which prescribes race and Hispanic ethnicity as distinct concepts that should be asked about in separate questions. In 2024, OMB updated the standards to stipulate that race and ethnicity be asked in one question and that a separate category be added to the single race and ethnicity question for Middle Eastern and North African. We examine the CPS microdata to tease out the effects that introduction of the 2024 standards might have on CPS labor force estimates across time. Our estimates show that individuals who indicate they are Middle Eastern or North African will likely be those who previously would have indicated that they are White, however their proportion of the population is small. In contrast, Hispanics make up a larger proportion of the population. “Other Race” responses in the CPS provide a lower bound estimate of the number of individuals who will identify as just Hispanic (Hispanic Alone) in a combined question while responses to the Hispanic ethnicity question provide an upper bound. Results from the Census Bureau’s National Content test suggest that the upper bound estimate is closer to the proportion of the population that will identify as Hispanic Alone, but there is insufficient information in the National Content test to determine how this will affect the various CPS labor force estimates. To address this issue, we calculate the labor force estimates corresponding to our lower and upper bounds However, we note that to obtain a more precise estimate of the effects changing the race and ethnicity questions on labor force estimates the two sets of questions should administered to the same respondents. One way of accomplishing this is to take advantage of the longitudinal aspect of the CPS. Individuals who initially provided their race and ethnicity using the 1997 standard questions can be asked their race and ethnicity using a combined question in subsequent months. An ongoing question is how the children of Hispanic immigrants who were born in the United States will view themselves. We therefore look at the tendency of individuals to identify as Hispanic because they were either born in a Hispanic country or were born in the U.S. but have one or two Hispanic parents.

摘要：在获取个人的种族和民族信息时，目前的《当前人口调查》（CPS）遵循1997年OMB标准，该标准规定种族和西班牙裔民族作为两个独立的概念，应通过不同的问题进行询问。在2024年，OMB更新了标准，要求将种族和民族在一个问题中询问，并在单一的种族和民族问题中增加一个“中东和北非”（Middle Eastern and North African，MENA）的分类。我们分析了CPS的微观数据，以探讨引入2024年标准可能对CPS劳动人口估计产生的影响。我们的估计显示，表示自己为中东或北非裔的个人很可能是那些以前会表示自己为白人的人，但他们在总人口中的比例较小。相比之下，西班牙裔占了更大比例。CPS中的“其他种族”回应提供了一个下限估计，即在一个综合问题中将自己标识为仅为西班牙裔（仅西班牙裔）的个体数量，而对西班牙裔民族问题的回应提供了一个上限估计。美国人口普查局的全国内容测试结果表明，上限估计更接近将标识为仅西班牙裔的总人口比例，但全国内容测试中没有足够的信息来确定这将如何影响各种CPS劳动人口估计。为解决这一问题，我们计算了与下限和上限对应的劳动人口估计。然而，我们指出，为了更精确地估计改变种族和民族问题对劳动人口估计的影响，应对同一组受访者使用两组问题进行调查。一种实现这一目标的方法是利用CPS的纵向特性。最初根据1997年标准问题提供其种族和民族信息的个人，可以在随后的月份中被询问以综合问题形式提供种族和民族信息。一个持续的问题是，出生在美国的西班牙裔移民的子女将如何看待自己。因此，我们研究了个人是否因出生在西班牙裔国家或在美国出生但有一或两个西班牙裔父母而倾向于标识为西班牙裔的情况。

关于选举前夕政治新闻的信念

Charles Angelucci, Michel Gutmann, and Andrea Prat #32802

Abstract: This paper develops a model of news discernment to explore the influence of elections on the formation of partisan-driven parallel information universes. Using survey data from news quizzes administered during and outside the 2020 U.S. presidential election, the model shows that partisan congruence’s impact on news discernment is substantially amplified during election periods. Outside an election, when faced with a true and a fake news story and asked to select the most likely true story, an individual is 4% more likely to choose the true story if it favors their party; in the days prior to the election, this increases to 11%.

摘要：本文构建了一个新闻辨别模型，以探讨选举对形成由党派驱动的平行信息宇宙的影响。利用在2020年美国总统选举期间及非选举期间进行的新闻测验调查数据，模型显示，选举期间党派一致性对新闻辨别的影响显著增强。在非选举期间，当面对一则真实新闻和一则假新闻并被要求选择最有可能是真实的新闻时，如果新闻有利于其党派，个体选择真实新闻的概率会增加4%；而在选举前几天，这一概率增加到11%。

动态优化与预算编制相遇：解开财务复杂性

Guidon Fenig and Luba Petersen #32821

Abstract: This paper explores sources of complexity in dynamic optimization, examining how individuals navigate variation in incomes, prices, and returns in ten-period consumption-saving decisions. Our findings reveal that dynamic optimization poses significant challenges, resulting in suboptimal choices even in straightforward scenarios with stable parameters, full information, no uncertainty, and opportunities to learn. These challenges intensify in scenarios involving complexities such as inflation and compounding returns, marked by a pronounced tendency to over-smooth consumption. Additionally, we introduce a novel budgeting calculator designed to assist with consumption planning and to collect valuable non-choice data on subjects' planning strategies and horizons—an approach not previously utilized in studies of dynamic optimization. We observe significant heterogeneity in planning horizons and ability to optimize given a chosen horizon. Complete planning leads to better performance in more complex scenarios, even when people do not optimally utilize the calculator. However, there is little reoptimization after the first period and participants tend to stick with suboptimal plans for most of their life cycle. The decision to plan is less influenced by the complexity of the economic environment and more by the length of the planning horizon.

摘要：本文探讨了动态优化中的复杂性来源，研究了个体在十期消费-储蓄决策中如何应对收入、价格和回报的变化。我们的研究发现，动态优化带来了显著的挑战，即使在参数稳定、信息充分、无不确定性且有学习机会的简单情境中，也会导致次优选择。这些挑战在涉及通货膨胀和复利回报等复杂情境中更加严重，表现为明显的消费过度平滑倾向。此外，我们引入了一种新型预算计算器，旨在帮助进行消费规划，并收集有关受试者规划策略和时间范围的有价值的非选择数据——这种方法在以往的动态优化研究中未曾使用。我们观察到，在规划时间范围和在选定时间范围内优化的能力方面存在显著的异质性。即使人们没有充分利用计算器，完整的规划仍能在更复杂的情境中带来更好的表现。然而，在第一个时期之后很少有重新优化的行为，参与者倾向于在其生命周期的大部分时间内坚持次优的计划。规划决策受经济环境复杂性的影响较小，而更多地受到规划时间范围长短的影响。

将“破坏”作为产业政策

Jin Liu, Martin Rotemberg, and Sharon Traiberman #32798

Abstract: We characterize sabotage, exemplified by recent U.S. policies concerning China's semiconductor industry, as trade policy. For some (but not all) goods, completely destroying foreigners’ productivity increases domestic real income by shifting the location of production and improving the terms of trade. The gross benefit of sabotage can be summarized by a few sufficient statistics: trade and demand elasticities and import and production shares. The cost of sabotage is determined by countries' relative unit labor costs for the sabotaged goods. We find important non-monotinicities: for semi-conductors, partially sabotaging foreign production would lower US real income, while comprehensive sabotage would raise it.

摘要：我们将破坏行为——以美国最近针对中国半导体产业的政策为例——归类为一种贸易政策。对于某些（但不是所有）商品，彻底摧毁外国的生产力可以通过改变生产的地理位置和改善贸易条件来增加国内实际收入。破坏带来的总收益可以通过一些足够的统计数据来概括：贸易和需求弹性、进口和生产份额。破坏的成本由国家在被破坏商品上的相对单位劳动成本决定。我们发现其中存在重要的非单调性：对于半导体来说，部分破坏外国生产会降低美国的实际收入，而全面破坏则会提高美国的实际收入。

大规模铁路撤资计划的空间影响：比钦大斧（Beeching Axe）

Steve Gibbons, Stephan Heblich, and Edward W. Pinchbeck #32800

Abstract: This paper investigates the reversibility of the effects of transport infrastructure investments, based on a programme that removed much of the rail network in Britain during the mid-20th Century. We find that a 10% loss in rail access between 1950 and 1980 caused a persistent 3% decline in local population relative to unaffected areas, implying that the 1 in 5 places most exposed to the cuts saw 24 percentage points less population growth than the 1 in 5 places that were least exposed. The cuts reduced local jobs and shares of skilled workers and young people.

摘要：本文研究了交通基础设施投资影响的可逆性，基于20世纪中期英国大规模撤除铁路网络的计划。我们发现，1950年至1980年间铁路通达度减少10%，导致受影响地区的当地人口相对于未受影响地区持续下降3%，这意味着受削减影响最大的五分之一地区人口增长比受影响最小的五分之一地区少了24个百分点。这些削减还减少了当地的就业机会、技能工人和年轻人所占比例。

世界各地的个人破产法与创新

Douglas Cumming, Randall Morck, Zhao Rong, and Minjie Zhang #32826

Abstract: Because corporate limited liability prevents creditors from founder’s personal assets, creditors often require founders of new, small and risky firms to contract around limited liability by pledging their personal assets as collateral for loans to their firms. This makes personal bankruptcy law (PBL) relevant to corporate finance. We find that pro-debtor PBL reforms increase the number of patents filed, citations to those patents, and début patents by firms with no previous patents. These reforms also redistribute innovation across industries in closer alignment to its distribution in the U.S., which we take to approximate industry innovative potential. These effects are driven by firms without histories of high-intensity patenting, and are damped in countries that impose minimum capital requirements on new firms. Firms with largescale legacy technology may avoid radical innovations that devalue that technology. Consequently, new, initially small and risky firms often develop the disruptive innovations that contribute most to economic growth. Consistent with this, we also find pro-debtor PBL reforms increasing value-added growth rates across all industries, and by larger margins in industries with more innovation potential. Our difference-in-differences regressions use patents and PBL reforms for 33 countries from 1990 to 2002, with subsequent years used to measure citations to patents in this period.

摘要：由于公司有限责任防止债权人从创始人的个人资产中追偿，债权人通常要求新成立的小型高风险企业的创始人通过将个人资产作为公司贷款的抵押品来规避有限责任。这使得个人破产法（PBL）与公司金融密切相关。我们发现，倾向于保护债务人的个人破产法改革增加了专利申请数量、这些专利的引用次数，以及没有历史专利记录的公司的首个专利申请。这些改革还使创新在各行业之间的分布更加接近美国的分布，我们认为这可以近似为行业的创新潜力。这些影响主要由过去没有高强度专利申请历史的公司驱动，并且在对新公司设定最低资本要求的国家中有所减弱。拥有大规模传统技术的公司可能会避免那些会使该技术贬值的激进创新。因此，新成立的、最初规模小且风险高的公司通常会开发出对经济增长贡献最大的颠覆性创新。与此一致的是，我们还发现，倾向于保护债务人的个人破产法改革提高了所有行业的增值增长率，特别是在创新潜力较大的行业中增幅更大。我们的差异中差异回归使用了33个国家1990年至2002年的专利和个人破产法改革数据，并通过后续年份的数据来衡量这一时期专利的引用情况。

全球霸权与过度特权

Carolin Pflueger and Pierre Yared #32775

Abstract: We present a dynamic two-country model in which military spending, geopolitical risk, and government bond prices are jointly determined. The model is consistent with three empirical facts: hegemons have a funding advantage, this advantage rises with geopolitical tensions, and war losers suffer from higher debt devaluation than victors. Even though higher debt capacity increases the military and financial advantage of the exogenously stronger country, it also gives rise to equilibrium multiplicity and the possibility that the weaker country overwhelms the stronger country with support from financial markets. For intermediate debt capacity, transitional dynamics exhibit geopolitical hysteresis, with dominance determined by initial conditions, unless war is realized and induces a hegemonic transition. For high debt capacity, transitional dynamics exhibit geopolitical fragility, where bond market expectations drive unpredictable transitions in dominance, and hegemonic transitions occur even in the absence of war.

摘要：我们提出了一个动态的双国模型，其中军费开支、地缘政治风险和政府债券价格共同决定。该模型与三个经验事实一致：霸权国家拥有融资优势，这种优势随着地缘政治紧张局势的加剧而上升，而战争失败者的债务贬值比胜利者更严重。尽管较高的债务能力增加了外生更强国家的军事和金融优势，但这也导致了均衡的多样性，并可能出现较弱国家在金融市场支持下压倒较强国家的情况。在中等债务能力下，过渡动态表现出地缘政治滞后效应，主导地位由初始条件决定，除非战争发生并引发霸权转移。在高债务能力下，过渡动态表现出地缘政治脆弱性，债券市场的预期驱动主导地位的不确定转变，甚至在没有战争的情况下也会发生霸权转移。

往期精选：

      重磅：学术财经•学术笔记全汇总

重磅：学术财经全球价值链专题学术笔记大汇总（附下载链接失效学术笔记推文）

重磅| 基金申请内部学习和交流

【学术笔记·第37篇】风险和全球供应链：我们知道什么和我们需要知道什么

【学术笔记·第36篇】各有所长：全球供应链风险敞口（Exposure）测度

【学术笔记·第35篇】日本生产者价格指数理论与实证：最终需求-中间需求加总系统

【学术笔记·第34篇】北美自由贸易的贸易和福利影响估计

【学术笔记 第33篇】 英属印度时期铁路：交通基础设施的影响评估（AER）

【学术笔记 第32篇】 技术、地理和贸易(经典EK模型）

【学术笔记 第31篇】2018年贸易战对美国物价和福利的影响

【学术笔记 第30篇】全球价值链和国家部门层面实际有效汇率