研究活動情報

• The Impact of Earmarked Taxes on Supply Curve Shifts: A Laboratory Experiment

  Shigeharu Okajima, Taro Shinoda, Yukihiko Funaki, Hiroko Okajima

  In this study, we examine how ordinary taxes and earmarked taxes influence tax pass-through in a market experiment. We hypothesize that tax pass-through is lower for earmarked taxes than for ordinary taxes and that this difference depends on market conditions, specifically the balance between the trade surpluses for sellers and buyers. Our findings confirm that ordinary taxes result in full tax pass-through, whereas earmarked taxes result in less pass-through. Under earmarked taxes, sellers adjust the level of pass-through based on their trade surplus relative to the buyers’ trade surplus. These results underscore the need to distinguish between tax types. The results of our study provide novel insights into the resource allocation effects of different tax types, offering significant implications for policymakers seeking to regulate goods with externalities through taxation.

  SAGE Publications, 2026年02月, Public Finance Review

  [査読有り]

  研究論文（学術雑誌）


• Gender diversity and firm performance: A multi‐level analysis of Japanese firms

  Hiroko Okajima, Shigeharu Okajima, Tomoka Ito, Atsushi Morimoto

  Abstract This study analyzes how gender diversity at the board, managerial, and employee levels relates to firm performance in Japan, using panel data from 311 listed companies (2006–2017). We apply instrumental variable estimation to address endogeneity. Across all levels and models, we find no statistically significant association between female representation and performance (measured by Tobin's Q and profit margin). These insignificant results may reflect structural or cultural barriers that limit the impact of diversity. The findings suggest that increasing female representation alone may be insufficient without broader organizational reform and institutional support mechanisms.

  Wiley, 2025年12月, Asian Economic Journal, 39(4) (4), 498 - 528

  [査読有り]

  研究論文（学術雑誌）


• Firm age and wage determination: evidence from matched employer–employee data in Japan

  Hiroko Okajima, Kazufumi Yugami, Atsushi Morimoto, Shigeharu Okajima, Kenta Nakamura

  Informa UK Limited, 2020年03月, Applied Economics Letters, 28(2) (2), 133 - 136

  [査読有り]

  研究論文（学術雑誌）


• What Motivates Donation? Empirical Evidence on Social Cooperation

  Shigeharu Okajima, Fukihiko Funaki, Hiroko Okajima

  2018年11月, Kokumin Keizai Zatsushi

  [査読有り]


• Impact of environmental regulation and the 2011 earthquake on the Japanese electricity industry

  Shigeharu Okajima, Hiroko Okajima

  2016年02月, 49, 223 - 249

  [査読有り]


• Estimation of Japanese price elasticities of residential electricity demand, 1990–2007

  Shigeharu Okajima, Hiroko Okajima

  Elsevier BV, 2013年11月, Energy Economics, 40, 433 - 440

  [査読有り]

  研究論文（学術雑誌）


• Analysis of energy intensity in Japan

  Shigeharu Okajima, Hiroko Okajima

  Elsevier BV, 2013年10月, Energy Policy, 61, 574 - 586

  [査読有り]

  研究論文（学術雑誌）

• 行動経済学会


• ヨーロッパ環境経済学会


• アメリカ経済学会


• 日本経済学会

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  競争的資金