Doctoral Dissertation Research in Economics: The Diffusion of Automobiles and Motortrucks in the United States in the 20th Century

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公法117-2)。这篇经济学博士论文研究了20世纪初和中期汽车和机动卡车在美国农场的扩散--具体地说，最后一英里全天候道路通道对扩散的影响，以及扩散对农业生产力的影响。这篇论文还考察了群体认同对公民和经济主体在考虑完全整合发达国家和发展中国家之间的资本、劳动力和贸易流动的协议(如在欧盟发生的情况)时对决策的影响。在美国，汽车和机动卡车几乎取代了铁路，成为长途客运和货运的首选。扩散的速度可能受到全天候道路的强大影响，农民是汽车和机动卡车的早期采用者之一。在今天的欠发达国家，机动车的销量有了巨大的增长，但缺乏最后一英里的道路通道减缓了机动车在农场的传播。衡量全天候道路通道对汽车和机动卡车使用的影响，对于可靠地模拟气候模式、世界交通网络、城市增长模式、人口结构和农业的未来至关重要。衡量汽车和机动卡车对农业生产率的影响，并将其分解为节省劳动力和节省土地的部分，对于在农业背景下更好地检验希克斯(1932)提出的诱致性创新假说至关重要：“生产要素相对价格的变化本身就是对发明的刺激，并对一种特定类型的发明--旨在节约使用已变得相对昂贵的要素--起到促进作用。”拟议或现有的放开资本、劳动力和贸易流动的国际协议经常遭到许多潜在签字国公民的政治反对，有时要么未能通过，要么退出，尽管人们压倒性地达成了共识，并高度相信此类协议将提高所有签字国的国民收入(并总体提高世界经济的整体效率)。了解群体认同对赞成或反对经济一体化的政治决策的影响，对于理解欧盟东扩、英国退欧和各种本土主义运动在发达国家涌现等事件至关重要。在关于道路准入对汽车和摩托车在农场普及的影响的论文章节中，根据1929年至1959年美国农业人口普查得出的一组县的面板数据，这段时期是机动车在农场传播最快的时期。在OLS规范中，道路准入是一个单一变量，具有县和州逐年影响和多重控制，道路准入与汽车使用率相关，机动卡车高出4.6%，汽车高出2.8%。IV基于多项式空间滞后工具的估计表明，道路通行导致汽车的使用率增加3.6%，汽车的使用率增加4.2%。这些平均值掩盖了道路通道影响的很大异质性。一个县生产的农作物和农产品的类型不同，道路通行的影响也有很大不同。在考察汽车和机动卡车对农业生产率的影响时，将估计农业企业的CES-Translog、Cobb-Douglas Translog(有交互作用项)和Log-log(不含交互作用项)生产函数，每个观察值都是单个县的农业企业。每个生产要素的影响将根据该县的作物构成而有所不同。人口、气候和天气控制变量将在县级得到控制。我们将考察全要素生产率的变化。汽车和机动卡车的影响将分别分解为节省劳动力和节省土地的组成部分。该实验考察了群体认同对经济一体化的影响，其动机是由Aranov和Palfrey(2015)采用的Metzler-Richards劳动力供给模型和实现中间选民定理的投票模型。人们可能会假设，在群体内情绪较强的人群中，选择的税率会更高，并且在给定税率的条件下，更强的群体内情绪将导致拥有更高技能劳动力的国家的选民不太可能投票支持融合。然而，组内身份对各国选民融合投票的最终影响在理论上是不确定的，因为虽然组内身份的条件是税率，但组内身份可能会导致赞成融合的票数减少，但组内认同会增加颁布的税率，而且在拥有更高技能劳动力的国家，主体投票支持融合的可能性正在增加。实验的结果将显示这两种影响中哪一种更大。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).This doctoral dissertation in economics examines the diffusion of automobiles and motortrucks on American farms in the early- and mid-20th century – specifically, the impact of last-mile all-weather road access on said diffusion, and the impact of said diffusion on agricultural productivity. This dissertation also examines the impact of group identity on the decisions of citizens and economic agents as they consider agreements to fully integrate capital, labor, and trade flows between a developed country and a developing country (as has occurred in the European Union). In the U.S., automobiles and motortrucks all but replaced railroads for long-distance travel, both passenger and freight. The pace of diffusion was likely powerfully influenced by access to all-weather roads and farmers were among the early adopters of automobiles and motortrucks. In less developed countries today, there is tremendous growth in the sales of motor vehicles, but lack of last-mile road access slows the diffusion of motor vehicles on farms. Measuring the impact of all-weather road access on uptake of automobiles and motortrucks is critical to reliably modelling the future of climate patterns, world transportation networks, urban growth patterns, demographics, and agriculture. Measuring the impact of automobile and motortruck uptake on agricultural productivity and decomposing the impact into a labor-saving and land-saving component, is critical to better examining in the context of agriculture the induced innovation hypothesis posited by Hicks (1932): "a change in the relative prices of the factors of production is itself a spur to invention, and to invention of a particular kind—directed to economizing the use of a factor which has become relatively expensive." Proposed or existing international agreements liberalizing capital, labor, and trade flows are often politically opposed by many citizens of prospective signatory nations, and sometimes either fail to be adopted or are withdrawn from, despite overwhelming consensus and a high degree of confidence that such deals will result in boosts to the national incomes of all signatory nations (and general efficiency gains to the world economy as a whole). Understanding the impact of group identity on political decisions in favor or against economic integration is critical to understanding events such as the eastward expansion of the European Union, the Brexit withdrawal, and various nativist movements surging throughout the developed world.For the dissertation chapter on the impact of road access on automobile and motortruck uptake on farms, a panel data set of counties is developed from U.S. Agricultural Censuses from 1929 to 1959, the period of most rapid diffusion of motor vehicles on farms. In OLS specifications with road access as a single variable with county and state-by-year effects and multiple controls, road access was associated with usage rates that were 4.6% higher for motortrucks and 2.8% higher for automobiles. IV estimation based on a polynomial spatial-lag instrument indicates that road access caused usage rates to be 3.6% higher for motortrucks and 4.2% higher for automobiles. These averages disguise a great deal of heterogeneity in the effect of road access. The impact of road access differed markedly by the types of crops and farm products produced in a county. When examining the impact of automobiles and motortrucks on agricultural productivity, a CES-translog, a Cobb-Douglas translog (with the interaction terms), and a log-log (without the interaction terms) production function of farm enterprises will be estimated, with each observation being the farm enterprises in a single county. The effect of each factor of production will be allowed to vary based on the crop composition of the county. Demographic, climate, and weather control variables will be controlled for at the county level. Changes in total factor productivity will be examined. The impact of automobiles and motortrucks will separately be decomposed into labor-saving and land-saving components. The experiment examining the impact of group identity on economic integration is motivated by the Metzler-Richards labor supply model as adapted by Agranov and Palfrey (2015) and a voting model that actualizes the Median Voter Theorem. One may hypothesize that taxation rates selected would be higher among populations with stronger in-group sentiment, and that conditional on a given taxation rate stronger in-group sentiment will cause the electorates of countries with higher-skilled workforces to be less likely to vote in favor of integration. However, the ultimate impact of in-group identity on the integration vote of the electorates of countries is theoretically indeterminate, as although conditional on a taxation rate in-group identity may cause fewer votes to be in favor of integration, in-group identity increases the tax rate enacted and the likelihood of a subject in countries with more-skilled workforces voting for integration is increasing in the tax rate. The results of the experiment will show which of these two effects is greater.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.