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A Study on Optimal Income Taxation with Welfare of Stigma and Rokyu

Research Project

Project/Area Number 19K01711
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 07050:Public economics and labor economics-related
Research InstitutionHokusei Gakuen University (2021-2022)
Hokkaido University (2019-2020)

Principal Investigator

Jun-ichi Itaya  北星学園大学, 経済学部, 教授 (20168305)

Project Period (FY) 2019-04-01 – 2023-03-31
Project Status Completed (Fiscal Year 2022)
Budget Amount *help
¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2021: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2020: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2019: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Keywordsスティグマ / 生活保護 / 不正受給者 / 漏給 / 統計的差別モデル / 納税者の怒りモデル / 進化ゲーム理論 / 定常均衡 / 安定性 / Stigma / Population Dynamics / Incomplete Take-up / needy / non-needy / welfare fraud / Population Dynamics / Incomplete Take-up / 最適所得税 / 進化ゲーム
Outline of Research at the Start

マーリーズ (1971)は一定の税収を確保しながら社会厚生を最大化する最適非線形所得税理論を構築して、いかなる条件下で累進所得税制を正当化できるかを考察した。他方、生活保護の制度設計はアカデミックだけでなく実際の政策立案において税制とは別個の問題として議論されている。これに対して、本研究では、生活保護の受給にスティグマが伴う結果、漏給(生活保護を必要とする者が受給要件を満たしているにもかかわらず受給しない状態)が生じている状況下で、2つの制度を一体化して、共通の政府予算制約下で一つの社会的厚生関数の最大化して、最適所得税構造および生活保護給付水準および基準額を同時に決定するモデルを構築する。

Outline of Final Research Achievements

Two theoretical models of stigma formation in welfare are developed by applying evolutionary game theory.
(1) In the dynamic statistical discrimination model, two long-run equilibria emerged. One equilibrium was that there were no unauthorized recipients, but no eligible recipients received benefits due to stigma (complete leakers). The other equilibrium was one in which some eligible recipients received benefits, but a large number of unauthorized recipients were created. (2)The dynamic taxpayer anger model shows that the only global equilibrium with both extremes is a mixed long-term equilibrium. In both equilibria, increasing benefits reduced the number of full leavers, but increased the number of unauthorized recipients. The most desirable policy outcome was an increase in the wage rate. The most desirable policy outcome was an increase in the wage rate, since an increase in the wage rate reduced both the number of full leakers and the number of unauthorized recipients.

Academic Significance and Societal Importance of the Research Achievements

理論的な結論は、なるべく不正受給者および完全漏給者(資格があるのに受給しない人)を減少させるための最適な生活保護制度をデザインするための政策指針を得ることができた。しかし、統計的差別モデルを使うか、納税者の怒りモデルを使うかによって、到達可能な長期均衡点が異なる。しかし、両モデルはほぼ同じ政策的なインプリケーションを与えている。特に、賃金率の上昇が一番の望ましい政策であることが示されている。給付水準を上げることが次に望ましい。本研究から得られた政策的インプリケーションは、ある程度の一般性および普遍性があるので、現実の生活保護制度をデザインする際に適用できると考えられる。

Report

(5 results)
  • 2022 Annual Research Report   Final Research Report ( PDF )
  • 2021 Research-status Report
  • 2020 Research-status Report
  • 2019 Research-status Report
  • Research Products

    (15 results)

All 2023 2022 2021 2020 2019 Other

All Int'l Joint Research (4 results) Journal Article (7 results) (of which Int'l Joint Research: 2 results,  Open Access: 3 results,  Peer Reviewed: 6 results) Presentation (2 results) (of which Int'l Joint Research: 2 results) Remarks (2 results)

  • [Int'l Joint Research] Wageningen University(オランダ)

    • Related Report
      2021 Research-status Report
  • [Int'l Joint Research] Keele Business School, Keele Universit(英国)

    • Related Report
      2020 Research-status Report
  • [Int'l Joint Research] Keele 大学経済学部(英国)

    • Related Report
      2019 Research-status Report
  • [Int'l Joint Research] ワーヘニンゲン大学 経済学(オランダ)

    • Related Report
      2019 Research-status Report
  • [Journal Article] Population Dynamics of Welfare Stigma: Welfare Fraud vs. Incomplete Take-Upt2023

    • Author(s)
      Jun-ichi Itaya and Ken-ichi Kurihara
    • Journal Title

      Hokkaido University Collection of Scholarly and Academic Papers

      Volume: 0 Pages: 1-35

    • Related Report
      2022 Annual Research Report
    • Open Access
  • [Journal Article] Existence, Uniqueness, and Comparative Statics of Nash Equilibrium in a Game of Voluntary Public Good Provision with Two Public Goods2022

    • Author(s)
      Suzuki,K, Miyakoshi,T, Itaya,J and Yamanashi,A.
    • Journal Title

      Metroeconomica

      Volume: 73 Issue: 2 Pages: 567-582

    • DOI

      10.1111/meca.12375

    • Related Report
      2021 Research-status Report
    • Peer Reviewed
  • [Journal Article] Equilibrium uniqueness in aggregative games: very practical conditions2021

    • Author(s)
      Jun-ichi Itaya・Pierre von Mouche
    • Journal Title

      Optimization Letters

      Volume: - Issue: 7 Pages: 2033-2058

    • DOI

      10.1007/s11590-021-01780-7

    • Related Report
      2021 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] Social Capital and the Status Externality2020

    • Author(s)
      Jun-ichi Itaya and Christopher Tsoukis
    • Journal Title

      International Journal of Econonomic Theory

      Volume: -

    • NAID

      120006368007

    • Related Report
      2020 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Are Moderate Leviathans Harmful to Tax Coordination?2020

    • Author(s)
      Jun-ichi Itaya and Chikara Yamaguchi
    • Journal Title

      FinanzArchiv

      Volume: 76 Pages: 165-190

    • Related Report
      2020 Research-status Report
    • Peer Reviewed
  • [Journal Article] Are Moderate Leviathans Harmful to Tax Coordination?2020

    • Author(s)
      Jun-ichi Itaya, Chikara Yamaguchi
    • Journal Title

      FinanzArchiv (FA)

      Volume: Online First Issue: 2 Pages: 1-26

    • DOI

      10.1628/fa-2020-0003

    • Related Report
      2019 Research-status Report
    • Peer Reviewed
  • [Journal Article] Heterogeneous Firms and Lobby Participation Decision2019

    • Author(s)
      Ahmed Qasim, Jun-ichi Itaya
    • Journal Title

      Economics Bulletin

      Volume: 39 Pages: 2415-2422

    • Related Report
      2019 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Presentation] Income Taxation, Equilibrium Indeterminacy and Taylor Rules: The Dual Roles of Money and Government Spending2019

    • Author(s)
      Junichi Itaya
    • Organizer
      Society for the Advancement of Economic Theory
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research
  • [Presentation] Evolutionary game of welfare stigma:2019

    • Author(s)
      Junichi Itaya
    • Organizer
      The Association for Public Economic Theory
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research
  • [Remarks] 北星学園大学教員情報 板谷淳一

    • URL

      https://www.hokusei.ac.jp/about/faculty/

    • Related Report
      2022 Annual Research Report
  • [Remarks] 北星学園大学教員情報 板谷淳一

    • URL

      http://www2.hokusei.ac.jp/hguhp/KgApp?resId=S000244

    • Related Report
      2020 Research-status Report

URL: 

Published: 2019-04-18   Modified: 2024-01-30  

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