1.0大阪大学大学院国際公共政策研究科 大阪大学法学部国際公共政策学科 | OSIPP（Osaka School of International Public Policy）https://www.osipp.osaka-u.ac.jp/ja/Libraryhttps://www.osipp.osaka-u.ac.jp/ja/news/author/library/rich600338<blockquote class="wp-embedded-content" data-secret="qJnrToIvLX"><a href="https://www.osipp.osaka-u.ac.jp/ja/news/achievement202605/">2026年5月の研究業績</a></blockquote><iframe sandbox="allow-scripts" security="restricted" src="https://www.osipp.osaka-u.ac.jp/ja/news/achievement202605/embed/#?secret=qJnrToIvLX" width="600" height="338" title="“2026年5月の研究業績” — 大阪大学大学院国際公共政策研究科 大阪大学法学部国際公共政策学科 | OSIPP（Osaka School of International Public Policy）" data-secret="qJnrToIvLX" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" class="wp-embedded-content"></iframe><script> /*! This file is auto-generated */ !function(d,l){"use strict";l.querySelector&&d.addEventListener&&"undefined"!=typeof URL&&(d.wp=d.wp||{},d.wp.receiveEmbedMessage||(d.wp.receiveEmbedMessage=function(e){var t=e.data;if((t||t.secret||t.message||t.value)&&!/[^a-zA-Z0-9]/.test(t.secret)){for(var s,r,n,a=l.querySelectorAll('iframe[data-secret="'+t.secret+'"]'),o=l.querySelectorAll('blockquote[data-secret="'+t.secret+'"]'),c=new RegExp("^https?:$","i"),i=0;i<o.length;i++)o[i].style.display="none";for(i=0;i<a.length;i++)s=a[i],e.source===s.contentWindow&&(s.removeAttribute("style"),"height"===t.message?(1e3<(r=parseInt(t.value,10))?r=1e3:~~r<200&&(r=200),s.height=r):"link"===t.message&&(r=new URL(s.getAttribute("src")),n=new URL(t.value),c.test(n.protocol))&&n.host===r.host&&l.activeElement===s&&(d.top.location.href=t.value))}},d.addEventListener("message",d.wp.receiveEmbedMessage,!1),l.addEventListener("DOMContentLoaded",function(){for(var e,t,s=l.querySelectorAll("iframe.wp-embedded-content"),r=0;r<s.length;r++)(t=(e=s[r]).getAttribute("data-secret"))||(t=Math.random().toString(36).substring(2,12),e.src+="#?secret="+t,e.setAttribute("data-secret",t)),e.contentWindow.postMessage({message:"ready",secret:t},"*")},!1)))}(window,document); //# sourceURL=https://www.osipp.osaka-u.ac.jp/wp-includes/js/wp-embed.min.js </script> https://www.osipp.osaka-u.ac.jp/wp-content/uploads/2026/03/Achievement-2.jpg20001000OSIPP基幹講座教員から報告があった研究業績をご紹介します。 ・細井友裕 先生　・前川和歌子 先生・松林哲也 先生　・髙田陽奈子 先生・川窪悦章 先生　・松島法明 先生Tomohiro Hosoi（論文）Tomohiro Hosoi, Tomoko Takahashi, African Agency in the Formation of Summit Diplomacy: An Analysis of Diplomatic Documents on TICAD I, Global Studies Quarterly, Volume 6, Issue 2, April 2026, ksag079, https://doi.org/10.1093/isagsq/ksag079　（査読あり）Abstract: “Africa + 1 summits” have emerged as a prominent prototype of contemporary African diplomacy. But it is important to examine how such summits were initially formed and how African states engaged in their institutional design. Earlier studies have yet to explain the preference of aid recipient countries for the summitry model over traditional bilateral schemes. Further, there is a limited understanding of how donors adjusted to the voices of aid recipients during negotiations to create such forums. This article examines the formative negotiations surrounding the launch of the Tokyo International Conference on African Development (TICAD) in the early 1990s. As the first Africa + 1 summit, TICAD constituted a pioneering case that shaped the development of summit diplomacy between Africa and external actors. Drawing on documents recently declassified by the Japanese Ministry of Foreign Affairs, obtained through information disclosure procedures, this article analyses how African states engaged with the inception of TICAD and influenced its institutional configuration. The analysis demonstrates that African states were not merely passive participants; they actively shaped Japan’s Africa policy during the 1990s by embedding their preferences in the conference’s design. Core features of TICAD and the broader Africa + 1 summit framework, such as the inclusive participation of all African states, including North Africa, and the establishment of follow-up mechanisms, emanated from African proposals during the preparatory process. By revealing how African agency operated at the formative stage of Africa + 1 summitry, this article contributes to scholarship on African diplomacy and the institutional evolution of summit diplomacy with external powers.Wakako Maekawa（論文）Cyrus Azimy, Marius Mehrl, Wakako Maekawa, Margherita Belgioioso, Daina Chiba“The Gender Gap in Peace and Conflict Journals, 2000–2024”International Studies Perspectives, 04 May 2026 （査読あり）https://doi.org/10.1093/isp/ekag002Abstract: While the issue of gender representation has gained increasing recognition across various academic disciplines, existing knowledge about the current state of gender representation in peace and conflict studies remains limited. This study aims to investigate gender representation in peace and conflict studies by examining a newly collected dataset of articles published in five academic journals representative of the field between 2000 and 2024. We find that, although the gender gap has not disappeared yet, it has narrowed over time. Our results show that increased collaboration, particularly across genders, appears to be an important driver of this trend. Additionally, we find evidence that gender differences in topical specialization exist in the field and that a gender gap in citation patterns exists for some of the field’s core journals. Continued efforts are needed to further improve gender representation.松林哲也（著書）松林哲也著『入門 現代政治学：選挙から政治家・政党、メディアまで』（中央公論新社、2026年）。https://www.chuko.co.jp/shinsho/2026/05/102908.html概要：そもそも政治とは何か？その体系は見えにくい。選挙で投票しなかったら不都合はあるのか。どんな政治家が選ばれ、誰の意見が通るのか。なぜ政党が新たに生まれるのか。経済成長・不平等との関係とは。有権者を幸せにしているのか。本書では、選挙、政治家、政党、有権者、メディア、民主主義などの基本概念をつなぎ合わせ、最新の政治学の理論と動向を紹介。データをもとに、民主政治の新しい見取り図を描き出す。髙田陽奈子（裁判意見書）髙田陽奈子「意見書」東京高等裁判所第１２民事部、令和7年（ネ）第3743号 自由権規約に基づく損害賠償請求控訴事件（2026年4月18日提出）。要旨：本件訴訟では、難民申請者である原告らに対して、被告である日本国が行った長期的かつ反復的な入管収容が、自由権規約9条1項の「何人も、恣意的に逮捕され又は抑留されない」という権利の侵害を構成するか否かが中心的な論点になっており、2025年に地裁判決が出て、現在、控訴審において訴訟手続が進んでいる。本意見書は、原判決と国による控訴理由書および答弁書を踏まえて、2023年に原審に提出した意見書を補足するものであり、主に、（１）国内法制度との整合性や国内法制度への影響という要素の、条約解釈における位置づけについて、（２）条約法条約31条上の諸要素の内容の理解について、（３）自由権規約委員会が採択する「一般的意見」の条約法条約31条・32条上の位置づけについて解説している。Takafumi Kawakubo（DP）Suzuki, Takafumi, Makoto Hasegawa, Masayoshi Hayashi and Takafumi Kawakubo“Information Constraints, Benchmark Dispersion, and Border Misreporting: Evidence from Japanese Customs Data”CIRJE Discussion Paper: CIRJE-F-1272, May 2026https://www.cirje.e.u-tokyo.ac.jp/research/dp/2026/2026cf1272ab.htmlAbstract: Border taxes are effective only insofar as customs can verify declarations at the border. We study whether higher border tax rates induce importers to understate the declared tax base, and whether such responses are concentrated where customs has less information from past transactions. Using confidential Japanese customs microdata linked to UN Comtrade, we construct HS6 product–partner–year cells for 2014–2021 and estimate how tax rates affect the trade-cost-adjusted log gap between partnerreported exports and Japan-reported imports, a reduced-form proxy for trade misreporting. The average semi-elasticity of this gap with respect to the tax rate is positive but statistically indistinguishable from zero. Yet the average masks sharp heterogeneity: responses are close to zero in information-rich lanes but economically meaningful in thin-information lanes, and somewhat larger where implied-unit-value dispersion is greater. A decomposition of mirror-data outcomes shows that the tax-responsive component of these discrepancies appears mainly in quantities rather than in implied unit values. The results imply that, even in a high-capacity setting, the effective incidence of border taxes depends on the lane-level information available for enforcement.Noriaki Matsushima（DP）Noriaki Matsushima“Monopolistic personalized pricing with a data advantage and cross-market harm”OSIPP Discussion Paper: DP-2026-E-006, 18 May 2026https://www.osipp.osaka-u.ac.jp/archives/DP/2026/DP2026E006.pdfAbstract: This paper develops a model of two monopoly markets linked by a common consumer budget constraint. A data-rich firm can set personalized prices in one market, whereas a traditional firm in the other must charge a uniform price. Personalized pricing can expand demand in the data-rich firm’s market, but because purchases come from a shared budget, it shrinks the residual demand facing the traditional firm and reduces its profit. When budgets are sufficiently tight, this adjacent-market distortion dominates same-market demand expansion, reducing total surplus. Thus, favorable same-market evidence alone is insufficient to support a benign assessment.Noriaki Matsushima（DP）Akio Kawasaki, Noriaki Matsushima“Competition between a public and a data-rich private firm: An application to digital health” OSIPP Discussion Paper: DP-2026-E-005, 8 May 2026https://www.osipp.osaka-u.ac.jp/archives/DP/2026/DP2026E005.pdfAbstract: Digital entrants in health care and health insurance often compete against public or mission-oriented organizations rather than only against private rivals. We develop a Hotelling model of mixed competition in which a private data-rich firm chooses the scope of consumer-data collection and then uses the acquired information to personalize offers. The rival supplies a standard service and is either a welfare-maximizing public firm or a profit-maximizing private firm. We characterize equilibrium data collection, prices, consumer surplus, profits, and social welfare. The private digital firm chooses a wider data-harvesting range when its rival is private than when its rival is public, because a public rival uses welfare-oriented pricing to discipline the induced market allocation rather than to maximize its own profit. The welfare ranking is non-monotonic in the value created by personalization. When the benefit from personalization is either small or large, competition against a public rival yields higher welfare; when the benefit is intermediate, competition against a private rival can dominate because it induces a broader rollout of personalized service. These results highlight that the welfare effects of digital entry depend jointly on data-driven personalization and the ownership objective of incumbent health-sector organizations.