2025.10.3
OSIPP基幹講座教員の9月の研究業績をご紹介します。
・生藤昌子 先生 ・松島法明 先生
・宮野紗由美 先生 ・山下拓朗 先生
・髙田陽奈子 先生 ・川窪悦章 先生
Masako Ikefuji（論文）
Masako Ikefuji, Jan R. Magnus, Andrey L. Vasnev, “The role of data and priors in estimating climate sensitivity,” Journal of the Royal Statistical Society Series C: Applied Statistics, qlaf047, 12 September 2025（査読あり）
https://doi.org/10.1093/jrsssc/qlaf047
Abstract: In Bayesian theory, the data together with the prior produce a posterior. We show that it is also possible to follow the opposite route, that is, to use data and posterior information (both of which are observable) to reveal the prior (which is not observable). We then apply the theory to equilibrium climate sensitivity as reported by the Intergovernmental Panel on Climate Change (IPCC) in an attempt to get some insights into the prior beliefs of the IPCC scientists.
Noriaki Matsushima （論文）
Qiuyu Lu, Noriaki Matsushima, Shiva Shekhar, “Welfare implications of personalized pricing in competitive platform markets: The role of network effects,” International Journal of Industrial Organization, Volume 103, Part B, 2025, 103200（査読あり）
https://doi.org/10.1016/j.ijindorg.2025.103200
Abstract: This study explores the welfare impact of personalized pricing for consumers in a duopolistic two-sided market, with consumers single-homing and developers affiliating with a platform according to their outside option. Personalized pricing, which is private in nature, cannot influence expectations regarding the network sizes, inducing the platforms to offer lower participation fees for developers. Those lower fees increase network benefits for consumers, allowing the platforms to exploit these benefits through personalized pricing. Personalized prices are higher when the network value for developers is high, benefiting competing platforms at the expense of consumers. These findings offer policy insights on personalized pricing.
Sayumi Miyano（論文）
Kim, In Song, Steven Liao, and Sayumi Miyano (2025) “How FDI reshapes host markets’ trade profile and politics.” American Journal of Political Science. Published online: 12 September 2025. （査読あり）
https://doi.org/10.1111/ajps.70010
Abstract: A fast-growing literature indicates that firms’ engagement in foreign direct investment (FDI) and trade is key to understanding deepening global value chains and their political implications. However, existing studies have mainly focused on the ramifications for FDI home countries while often overlooking the firm-product level interactions between FDI and trade, where their interdependencies manifest. This study examines how firms’ FDI reshapes host countries’ trade profiles at this level, empowering new political coalitions for trade liberalization. Analyzing greenfield FDI projects globally since 2003, we find that hosts experienced an average increase of over 45 export products in the following year. To overcome the challenges of connecting firms to products, we link FDI data with Vietnamese customs records. We find that Vietnamese export (import) volumes of FDI-related products increased by 90% (30%) within 4 years of initial investments. Importantly, these products also benefited from more substantial tariff cuts in bilateral Free Trade Agreements.
Takuro Yamashita （論文）
Yusuke Yamaguchi, Takuro Yamashita (2025) “Robust predictions and hard information in the market for lemons,” Economics Letters, Volume 256, October 2025（査読あり）
https://doi.org/10.1016/j.econlet.2025.112568
Abstract: The literature on informationally robust predictions has focused mostly on soft information. In a stylized adverse selection model, we show that hard information enables trade, even when the unique equilibrium outcome without it is no-trade.
Takuro Yamashita （論文）
Takeshi Murooka, Takuro Yamashita (2025) “Optimal Trade Mechanisms with Adverse Selection and Inferential Naivety,” American Economic Journal: Microeconomics, （査読あり）Forthcoming
https://www.aeaweb.org/articles?id=10.1257/mic.20230019&&from=f
Abstract: We study an adverse selection environment in which a buyer’s inferential ability is heterogeneous: A rational type correctly infers the value of the good from a seller’s offer, whereas a naive type is inattentive to the correlation between the seller’s private information and the offer. We characterize the optimal menu mechanism that maximizes the seller’s profits or trade surplus. Notably, no matter how severe the adverse selection is, all types of buyers trade. We then provide conditions under which the menu mechanism is optimal among all general mechanisms. A consumer-protection policy that limits the naive buyer’s loss is also investigated.
髙田陽奈子 （著書）
「国内人権機関」pp.13-14、小坂田裕子他編『アクティブラーニング国際人権法』（法律文化社、2025年）
https://www.hou-bun.com/cgi-bin/search/detail.cgi?c=ISBN978-4-589-04434-1
概要：本書は、学部生や大学院生を主な対象とした国際人権法の教科書である。この教科書における「国内人権機関」の項目を執筆し、パリ原則や国内人権機関グローバル連盟などの国内人権機関にかかわる基本事項について説明し、国連の人権条約機関の関連する実践や、日本における国内人権機関の設置に関する動向について解説した。
Takafumi Kawakubo （Discussion Paper）
Takafumi Kawakubo, Takafumi Suzuki “Spillovers through Supply Chains: How large plant openings affect local supplier firms”, RIETI Discussion Paper Series 25-E-083, September 2025
https://www.rieti.go.jp/jp/publications/nts/25e083.html
Abstract: This study examines how becoming a supplier to a newly established large-scale plant influences the performance of incumbent small plants. Exploiting detailed plant-level data, records of new large plant openings, and supply chain information, we construct a quasi-experimental setting based on the spatial distribution of new entrants. Our event-study estimates show that while local supplier plants benefit significantly—both statistically and economically—from large-scale plants, non-supplier plants in the same region face negative impacts, likely due to intensified competition spurred by the newly-contracted suppliers. The results underscore that such entries create “winners and losers” not only across different regions but also within the same locality. From a policy perspective, these insights highlight the importance of facilitating effective partnerships between large-scale entrants and local suppliers, as well as offering support to disadvantaged non-supplier firms. Overall, our findings illuminate the nuanced local economic consequences of large-scale plant entries and offer guidance for future industrial and regional policies.