American Economic Review 2023年第9期 ? Vol. 113, Issue 9 ? ? ——更多動態(tài)，請持續(xù)關注gzh：理想主義的百年孤獨

? ? ? ? Worth Your Weight: Experimental Evidence on the Benefits of Obesity in Low-Income Countries 值得你的體重:低收入國家肥胖益處的實驗證據(jù) Elisa Macchi I study the economic value of obesity—a status symbol in poor countries associated with raised health risks. Randomizing decision-makers in Kampala, Uganda to view weight-manipulated portraits, I find that obesity is perceived as a reliable signal of wealth but not of beauty or health. Thus, leveraging a real-stakes experiment involving professional loan officers, I show that being obese facilitates access to credit. The large obesity premium, comparable to raising borrower self-reported earnings by over 60 percent, is driven by asymmetric information and drops significantly when providing more financial information. Notably, obesity benefits and wealth-signaling value are commonly overestimated, suggesting market distortions. ? ? ? ? ? Imperfect Financial Markets and Investment Inefficiencies 金融市場不完善和投資效率低 Elias Albagli, Christian Hellwig and Aleh Tsyvinski We analyze the consequences of noisy information aggregation for investment. Market imperfections create endogenous rents that cause overinvestment in upside risks and underinvestment in downside risks. In partial equilibrium, these inefficiencies are particularly severe if upside risks are coupled with easy scalability of investment. In general equilibrium, the shareholders' collective attempts to boost value of individual firms leads to a novel externality operating through price that amplifies investment distortions with downside risks but offsets distortions with upside risks. ? ? A Road to Efficiency through Communication and Commitment 通過溝通和承諾提高效率之路 Ala Avoyan and Jo?o Ramos ?We experimentally examine the efficacy of a novel pre-play institution in a well-known coordination game—the minimum-effort game—in which coordination failures are robust and persistent phenomena. This new institution allows agents to communicate while incrementally committing to their words, leading to a distinct theoretical prediction: the efficient outcome is uniquely selected in the extended coordination game. We find that commitment-enhanced communication significantly increases subjects' payoffs and achieves higher efficiency levels than various nonbinding forms of communication. We further identify the key ingredients of the institution that are central to achieving such gains. ? Market Structure, Oligopsony Power, and Productivity 市場結構、寡頭力量和生產(chǎn)率 ? Michael Rubens I examine the effects of oligopsony power on allocative efficiency and income redistribution by studying a size regulation in the Chinese tobacco industry that led to ownership consolidation. I show that separate identification of input price markdowns, goods price markups, and productivity is challenging when a subset of inputs is nonsubstitutable, which often holds for materials, and construct and estimate a model to overcome this challenge. I find that the regulation increased input price markdowns by 37 percent on average. This increase in oligopsony power led to a decline in allocative efficiency and redistributed income away from rural households. ? ? ? The Macroeconomics of the Greek Depression 希臘大蕭條的宏觀經(jīng)濟 ? Gabriel Chodorow-Reich, Loukas Karabarbounis and Rohan Kekre Greece experienced a boom until 2007, followed by a collapse of unprecedented magnitude and persistence. We assess the sources of the boom and the bust, using a rich estimated dynamic general equilibrium model. External demand and government consumption fueled the boom in production, whereas transfers fueled the boom in consumption. Different from the standard narrative, wages and prices declined substantially during the bust. Tax policy accounts for the largest fraction of the bust in production, whereas uninsurable risk accounts for the bust in consumption and wages. We assess how the composition of fiscal adjustment and bailouts affected the crisis. ? ? ? ? ? Second-Best Fairness: The Trade-off between False Positives and False Negatives 第二好的公平性：誤報和漏報之間的權衡 ? Alexander W. Cappelen, Cornelius Cappelen and Bertil Tungodden A main focus in economics is how to design optimal policies in second-best situations, which often requires a trade-off between giving some individuals more than they deserve, false positives, and others less than they deserve, false negatives. This paper provides novel evidence on people's second-best fairness preferences from large-scale experimental studies in the United States and Norway. The majority of people are more concerned with false negatives than with false positives, but we document substantial heterogeneity in second-best fairness preferences between the countries and across the political spectrum. The findings shed light on the political economy of social insurance and redistribution. ? Choice Screen Auctions Michael Ostrovsky Choice screen auctions have been recently deployed in 31 European countries, allowing consumers to choose their preferred search engine on Google's Android platform instead of being automatically defaulted to Google's own search engine. I show that a seemingly minor detail in the design of these auctions—whether they are conducted on a "per appearance" or a "per install" basis—plays a major role in the mix and characteristics of auction winners and, consequently, in their expected market share. Furthermore, per install auctions distort search engines' incentives. Empirical evidence from Android choice screen auctions conducted in 2020 is consistent with my theoretical results. ? ?