Updated on 2024/05/17

写真a

 
OKAMOTO Akira
 
Organization
Faculty of Humanities and Social Sciences Professor
Position
Professor
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Degree

  • Ph.D. (Economics) ( Kyoto University )

  • Master (Economics) ( Kyoto University )

Research Interests

  • 少子高齢化社会

  • 年金改革

  • 税制改革

  • 社会保障制度改革

  • 格差問題

  • 人口減少化社会

  • Economic Policy

  • Tax Reform

  • Social Security Reform

  • 経済政策

  • 階級社会

  • 社会の階層化

  • 所得階層の移動

  • 移民政策

  • 経済格差

  • 所得格差

  • 所得階層

  • 少子化対策

Research Areas

  • Humanities & Social Sciences / Public economics and labor economics

  • Humanities & Social Sciences / Money and finance

  • Humanities & Social Sciences / Economic policy

Education

  • Kyoto University   経済学研究科  

    - 1997

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    Country: Japan

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  • Kyoto University    

    - 1997

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  • Kyoto University    

    - 1995

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  • Kyoto University   経済学研究科  

    - 1995

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    Country: Japan

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  • Kyoto University   経済学部  

    - 1989

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    Country: Japan

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  • Kyoto University    

    - 1989

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  • Kyoto University   博士(経済学)  

    2004.3

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Research History

  • - 岡山大学社会文化科学研究科 教授

    2007.10

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  • - Professor,Graduate School of Humanities and Social Sciences,Okayama University

    1997

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Professional Memberships

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Committee Memberships

  • 岡山県   税制懇話会 委員  

    2022.4 - 2024.3   

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    Committee type:Municipal

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  • 独立行政法人日本学術振興会   科学研究費委員会専門委員  

    2014.12 - 2016.11   

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    第1段審査(書面審査)委員 「財政・公共経済」

  • 独立行政法人日本学術振興会   科学研究費委員会専門委員  

    2011.12 - 2013.11   

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    第1段審査(書面審査)委員 「財政・公共経済」

  • 内閣府経済社会総合研究所   「平成18年度 少子高齢化の下での持続的成長と財政再建に関する国際共同研究調査委員会」委員  

    2006.9 - 2007.3   

  • 独立行政法人経済産業研究所   「最適負担率研究会」委員  

    2004.7 - 2006.7   

 

Papers

  • The Optimum Quantity of Debt for an Aging Japan: Welfare and Demographic Dynamics Reviewed

    Akira Okamoto

    The Japanese Economic Review   75 ( 3 )   (in press)   2024.5

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    Authorship:Lead author, Last author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1007/s42973-024-00156-7

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  • Intergenerational earnings mobility and demographic dynamics: Welfare analysis of an aging Japan Reviewed

    Akira Okamoto

    Economic Analysis and Policy   74   76 - 104   2022.6

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    Authorship:Lead author, Last author, Corresponding author   Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.eap.2022.01.006

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  • Immigration Policy and Demographic Dynamics: Welfare Analysis of an Aging Japan Reviewed

    Akira Okamoto

    Journal of the Japanese and International Economies   62   Article - 101168   2021.12

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    Authorship:Lead author, Last author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

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  • Childcare Allowances and Public Pensions: Welfare and Demographic Effects in an Aging Japan Reviewed

    Akira Okamoto

    The B.E. Journal of Economic Analysis and Policy   20 ( 2 )   Article 20190067   2020.4

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    Authorship:Lead author, Last author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

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  • WELFARE ANALYSIS OF PENSION REFORMS IN AN AGEING JAPAN Reviewed

    Akira Okamoto

    JAPANESE ECONOMIC REVIEW   64 ( 4 )   452 - 483   2013.12

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:WILEY-BLACKWELL  

    This paper uses a computable general equilibrium model with overlapping generations to explore the effects of different public pension schemes on economic welfare, and intergenerational and intragenerational equity. Besides the benchmark case based on the 2004 public pension reform, the present paper considers two alternative reforms: financing the basic pension benefit through a consumption tax, and eliminating the earnings-related pension benefit. The simulation results suggest that even the consumption-tax financing of only the basic pension, namely, the combination of both reforms, might not improve overall economic welfare, although it increases economic output by inducing capital formation.

    DOI: 10.1111/jere.12002

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  • Public Pension Reform in Japan Reviewed

    Akira Okamoto

    Economic Analysis and Policy   40 ( 2 )   179 - 208   2010

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Elsevier  

    This paper aims to establish guidelines for public pension reform in Japan, using a numerical simulation approach. The paper introduces the example of a minimum guaranteed pension in the Swedish pension system and compares this with the basic pension in Japan's public pension system, with regard to methods of income redistribution through a public pension scheme. Simulation results show that the switch from the basic pension to the guaranteed pension does not always generate favorable results. If we consider a public pension program with the same scale as the current Japanese program, the highest level of social welfare is attained when a public pension system consists of only a basic pension and is financed by a consumption tax.

    DOI: 10.1016/S0313-5926(10)50024-9

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  • Optimal Tax Combination in an Aging Japan Reviewed

    OKAMOTO Akira

    International Economic Journal   21 ( 1 )   91 - 114   2007.3

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  • Simulating fundamental tax reforms in an aging Japan Reviewed

    Akira Okamoto

    Economic Systems Research   17 ( 2 )   163 - 185   2005.6

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    Language:English   Publishing type:Research paper (scientific journal)  

    This paper studies in a quantitative way the macroeconomic and welfare effects of introducing progressive expenditure taxation, in a situation of the aging of the Japanese population. It undertakes a simulation analysis taking account of the general equilibrium effects of intragenerational inequality, which increases with a transition to an aging society. The simulation results suggest that progressive expenditure taxation has advantages over progressive labor income taxation on the grounds of efficiency and equity. Thus, a shift to progressive expenditure taxation can overcome the large welfare loss that would occur under the current tax system as Japan ages. © 2005 Taylor &amp
    Francis Group Ltd.

    DOI: 10.1080/09535310500114911

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  • Simulating progressive expenditure taxation in an aging Japan Reviewed

    A Okamoto

    JOURNAL OF POLICY MODELING   27 ( 3 )   309 - 325   2005.4

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE INC  

    This paper investigates the quantitative effects of tax reform from progressive labor income taxation toward progressive expenditure taxation on efficiency and equity in Japan, a society with an aging population. To analyze this problem, we employ a comparative steady state simulation approach for an extended life-cycle general equilibrium model of overlapping generations with different lifetime earnings ability. The simulation results suggest some advantages of a new tax system of progressive expenditure taxation. (c) 2005 Society for Policy Modeling. Published by Elsevier Inc. All rights reserved.

    DOI: 10.1016/j.jpolmod.2004.08.011

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  • Pension Reform for an Aging Japan: Welfare and Demographic Dynamics

    Akira OKAMOTO

    Okayama University Discussion Paper   No. I-118   2024.3

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    Authorship:Lead author, Last author, Corresponding author   Language:English   Publishing type:Research paper (other academic)  

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  • The Optimum Quantity of Debt for an Aging Japan: Welfare and Demographic Dynamics Reviewed

    Akira Okamoto

    Okayama University Discussion Paper   I-113   1 - 52   2022.9

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    Authorship:Lead author, Last author, Corresponding author   Publishing type:Research paper (bulletin of university, research institution)   Publisher:Elsevier BV  

  • コロナ危機と地方創生 ―地域の持続可能性を評価する新たな指標― Invited

    岡本 章

    岡山大学産業経営研究会研究報告書   第55集   1 - 32   2022.5

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  • Silver Democracy and Electoral System: Political Feasibility of Policy Reform Plans in an Aging Japan

    OKAMOTO Akira

    Okayama Economic Review   51 ( 2/3 )   123 - 129   2020.3

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    Language:English   Publishing type:Research paper (bulletin of university, research institution)  

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  • 所得階層の移動促進、社会全体の損失回避を Invited

    岡本 章

    政策ブログ『財政・社会保障研究会』、日本経済研究センター   2019.6

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

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  • シルバー民主主義を考える:選挙制度の大胆改革急げ Invited

    岡本 章

    日本経済新聞『経済教室』   朝刊 ( 17面 )   2017.5

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  • 年金給付削減は政治的に実現できるのか Invited

    岡本 章

    中央公論新社『中央公論』   130 ( 7 )   42 - 54   2016.7

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    Language:Japanese   Publisher:中央公論新社  

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  • Simulating Public Pension Reforms in an Aging Japan: Welfare Analysis with LSRA Transfers Invited

    岡本 章

    Public Policy Review   9 ( 4 )   597 - 632   2013.9

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  • 少子高齢・人口減少社会における公的年金改革 ―LSRA による所得移転を含む厚生分析 ― Invited

    岡本 章

    財務省財務総合政策研究所 『フィナンシャル・レビュー』   ( 115 )   23 - 52   2013.6

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  • Tax Policy in Aging Japan Reviewed

    Okamoto Akira

    Journal of International Economic Studies   23   43 - 58   2009.3

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    Language:English   Publisher:The Institute of Comparative Economic Studies, Hosei University  

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  • 日本の公的年金改革 Invited

    岡本 章

    日本財政学会叢書 『財政研究』(日韓特別セッション)   4   92 - 102   2008.10

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  • 少子高齢化と国民負担率 Invited

    岡本 章

    橘木俊詔編著 『政府の大きさと社会保障制度』   第2章   67 - 94   2007.6

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  • 基礎年金・最低保障年金の分析 Invited

    岡本章, 島俊彦

    橘木俊詔編著 『政府の大きさと社会保障制度』   第4章   121 - 153   2007.6

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  • 国民の受益・負担と政府の大きさ Invited

    橘木俊詔, 岡本章, 川出真清, 畑農鋭矢, 宮里尚三

    橘木俊詔編著『政府の大きさと社会保障制度』   第1章   31 - 66   2007.6

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  • 望ましい財源調達手段 Invited

    橘木俊詔, 岡本章, 川出真清, 畑農鋭矢, 宮里尚三, 島俊彦, 石原章史

    橘木俊詔編著『政府の大きさと社会保障制度』   第3章   95 - 120   2007.6

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  • 少子高齢化と租税政策 Invited

    岡本 章

    橘木俊詔編著 『日本経済の実証分析』   第5章   91 - 116   2007.3

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  • An Optimal Rate of the National Burden in an Aging Japan Reviewed

    Okamoto Akira

    The Kyoto Economic Review   75 ( 1 )   13 - 34   2006.6

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    Language:English   Publisher:Graduate School of Economics, Kyoto University  

    This paper examines an optimal rate of the national burden to establish guidelines for fiscal reform in Japan&rsquo;s graying society. The paper looks at Japanese tax and social security systems through an extended life-cycle general equilibrium simulation model. It explicitly considers the benefits that the government provides to households, which enables us to comprehensively evaluate the balance between benefits and burdens. Simulation results show that an optimal rate of the national burden is high when households put a great utility weight on the benefits coming from public services, and that it is low when the degree of publicness of government expenditure is high. The results also suggest that an optimal rate of the national burden would rise as Japan ages and may exceed 50% during the rapid aging of its population.<br>

    DOI: 10.11179/ker.75.13

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  • Integration of tax and social security systems - On the financing methods of a public pension scheme in a pay-as-you-go system Invited

    A Okamoto, T Tachibanaki

    SOCIAL SECURITY REFORM IN ADVANCED COUNTRIES   Chapter 7   132 - 160   2002

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:ROUTLEDGE  

    This chapter explores whether or not the contributions to public pension scheme in the pay-as-you-go system should be substituted by general taxes, e.g. a progressive labor income tax or a consumption tax. The chapter also investigates whether or not such possible integration of tax and social security systems is desirable from the aspects of both efficiency and equity. To analyze the problem, we adopt an extended lifecycle general equilibrium model of overlapping generations with heterogeneity in the ability of labor supply, using the household expenditure survey data. The simulation results indicate that a progressive expenditure tax with full integration is the most desirable policy.

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Books

  • コロナ危機と地方創生 ―地域の持続可能性を評価する新たな指標―

    岡本 章( Role: Sole author)

    『岡山大学産業経営研究会研究報告書』第55集  2022.5 

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    Responsible for pages:1-32   Language:Japanese

  • 年金給付削減は政治的に実現できるのか

    岡本 章( Role: Sole author)

    中央公論新社『中央公論』  2016.7 

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    Total pages:第130巻第7号   Responsible for pages:42-54   Book type:General book, introductory book for general audience

  • 日本の公的年金改革

    岡本 章( Role: Sole author ,  日韓特別セッション)

    日本財政学会叢書 『財政研究』 第4巻, 有斐閣, 92-102.  2008 

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  • 日本経済の実証分析 ―失われた10年を乗り越えて―

    東洋経済新報社  2007 

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  • 政府の大きさと社会保障制度 ―国民の受益・負担からみた分析と提言―

    東京大学出版会  2007 

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  • Tax Policy for Aging Societies: Lessons from Japan

    岡本 章

    Springer  2004 

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  • Tax and Social Security Reforms in an Aging Japan

    岡本 章

    Okayama University Economic Research Series No. 29  2003 

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MISC

  • 少子化・人口減対策/出産、育児の安心感醸成を Invited

    岡本 章

    山陽新聞『2023 統一地方選 特別寄稿』(3面)   2023.4

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    Authorship:Lead author, Last author, Corresponding author   Language:Japanese   Publishing type:Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media)  

  • 新型コロナウイルスと人口減少 Invited

    岡本 章

    政策ブログ『財政・社会保障研究会』 日本経済研究センター   2021.10

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    Authorship:Lead author, Last author, Corresponding author  

  • 実質賃金が増える政府債務の規模 Invited

    岡本 章

    政策ブログ『財政・社会保障研究会』 日本経済研究センター   2021.6

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  • 所得階層の移動促進、社会全体の損失回避を Invited

    岡本 章

    政策ブログ『財政・社会保障研究会』 日本経済研究センター   2019.6

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    Authorship:Lead author, Last author, Corresponding author  

  • シルバー民主主義を考える:選挙制度の大胆改革急げ Invited

    岡本 章

    日本経済新聞『経済教室』   朝刊 ( 17面 )   2017.5

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    Authorship:Lead author, Last author, Corresponding author  

  • 「狛江市議会に世代別選挙区制度を」提案者に聞く Invited

    内山惠一・岡本章

    中央公論新社『中央公論』   第130巻第7号 ( 54-57 )   2016.7

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    Publishing type:Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media)  

  • 「狛江市議会に世代別選挙区制度を」提案者に聞く Invited

    内山惠一, 岡本章

    中央公論新社『中央公論』(インタビュー記事)   130 ( 7 )   54 - 57   2016.7

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    Language:Japanese   Publisher:中央公論新社  

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  • Introduction of Progressive Expenditure Taxation to Japan

    Okamoto Akira

    Okayama economics review   36 ( 4 )   555 - 563   2005

  • Comments on “Effect of Economic Crisis on Income Distribution in Korea” by Professor Jun Young Kim (Sungkyunkwan University, Korea)

    Okamoto, A

    「ラウンドテーブル:財政の効率性・公平性について」報告書 第4章 内閣府経済社会総合研究所   2002

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  • Income Distribution and Tax Reforms in Aging Japan

    Okamoto Akira

    Okayama economic review   32 ( 2 )   243 - 282   2000

  • Heterogeneous Labor Endowments and Tax Reforms in Aging Japan : Progressive Taxes and Intragenerational Redistribution

    Okamoto Akira

    Okayama economic review   32 ( 1 )   1 - 48   2000

  • アンケート調査にみる郵便貯金の役割

    岡本章

    郵便貯金に関する特別委託研究「郵便貯金と地域社会に関する研究」   1998

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  • 社会保障負担は“累進消費税”の導入で賄え(橘木俊詔との共著)

    橘木 俊詔, 岡本 章

    「週刊エコノミスト」毎日新聞社   3月18日号、76-79 ( 12 )   76 - 79   1997

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    Language:Japanese   Publisher:毎日新聞社  

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  • 高齢化社会における利子所得税のディストーション効果について

    京都大学経済論叢   第157巻第4号 16-29・第158巻第2号、58-74   1996

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Presentations

  • Pension Reform for an Aging Japan: Welfare and Demographic Dynamics Invited

    Akira OKAMOTO

    AGI (Asian Growth Research Institute) Seminar  2024.3.21 

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    Language:English   Presentation type:Oral presentation (invited, special)  

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  • Simulating the Comprehensive Effects of Intergenerational Earnings Mobility in an Aging Japan Invited

    Akira Okamoto

    The International Symposium on Business and Economic Studies  2019.11.15 

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    Language:English   Presentation type:Oral presentation (general)  

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  • The Optimum Quantity of Debt for a Depopulating and Aging Japan: Welfare Level or Future Population?

    Akira Okamoto

    The 13th Irvine-Japan Conference on Public Policy, Irvine  2017.2.3 

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    Language:English   Presentation type:Oral presentation (general)  

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  • Child Allowances and Public Pensions: Welfare Effects and Political Feasibility of Reforms in a "Silver Democracy"

    International Symposium on "Demography and Pensions"  2015 

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  • Child Allowances and Public Pension: Welfare Effects of their Reforms and Political Feasibility under the "Silver Democracy"

    日本経済学会春季大会  2015 

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  • Child Allowances and Public Pension: Welfare Effects of their Reforms and Political Feasibility under the "Silver Democracy"

    関西公共経済学研究会  2015 

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  • Pareto-Improving Pension Reform in an Aging Japan

    The 64th Annual Meeting of the Japan Fiscal Science Association, Japan-Korea Special Session  2009 

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  • Public Pension Reform in Japan: Basic Pension or Minimum Guaranteed Pension?

    The 64th Annual Meeting of the Japan Fiscal Science Association, Japan-Korea Special Session  2007 

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  • 少子高齢化と租税政策

    淡路島コンファレンス『日本経済はどのように機能しているか』(京都大学COEプロジェクト)  2006 

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  • Optimal Tax Combination in an Aging Japan

    The 62nd Congress of the International Institute of Public Finance  2006 

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  • Optimal Tax Combination in an Aging Japan

    International Conference on “International Research Project on Aging (Japan, China, Korea)  2006 

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  • Optimal National Burden Rate and an Aging Japan

    Spring Seminar of Department of Economics at the University of Wisconsin-Milwaukee  2006 

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  • Optimal National Burden Rate and an Aging Japan

    日本財政学会第62回大会  2005 

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  • Optimal National Burden Rate and an Aging Japan

    The 61st Congress of the International Institute of Public Finance  2005 

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  • Simulating Structural Tax Reforms in Aging Japan

    2004年度日本経済学会秋季大会  2004 

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  • Inheritance Taxes and Tax Reforms in an Aging Japan

    International Conference on the "International Research Project on Aging (Japan, China, and Korea)"  2004 

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  • Within-cohort Inequality and Tax Reforms in Aging Japan

    "International Forum on Tax Reforms in Japan," Economic and Social Research Institute (ESRI), Cabinet Office  2002 

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  • Within-Cohort Inequality and Tax Reforms in Aging Japan

    "International Forum on Tax Reforms in Japan" organized by Economic and Social Research Institute (ESRI)  2002 

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  • Within-Cohort Inequality and Tax Reforms in Aging Japan

    International Forum on Tax Reforms in Japan” organized by Economic and Social Research Institute (ESRI)  2002 

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  • ライフサイクル一般均衡モデルによるシミュレーション分析

    国立社会保障・人口問題研究所:社会保障に関するOLGモデル・ワークショップ  2001 

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  • 所得税と支出税

    経済産業省政策局 第3回財政研究会  2001 

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  • ライフサイクル一般均衡モデルによるシミュレーション分析

    社会保障に関するOLGモデル・ワークショップ, 国立社会保障・人口問題研究所  2001 

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  • Integration of Tax and Social Security Systems: On the Financing Methods of a Public Pension Scheme in Pay-as-You-Go System

    2000 Annual Meeting of the Japan Fiscal Science Association  2000 

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  • Progressive Expenditure Taxation in Aging Japan

    2000 Annual Meeting of the Japanese Economic Association  2000 

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  • Integration of Tax and Social Security Systems

    2000 Annual Meeting of the Japan Fiscal Science Association  2000 

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  • Integration of Social Security and Tax Systems

    International Conference on "Social Security Reform in Advanced Countries"  1999 

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  • Integration of Social Security and Tax Systems

    International Conference on "Social Security Reform in Advanced Countries"  1999 

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  • 経済の動向 ―試される日本経済の変革力―

    岡山県自治研修所  1998 

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Awards

  • 「有意義な審査意見を付した科研費審査委員」として表彰される

    2016   日本学術振興会  

    岡本 章

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  • 安倍フェロー

    2015  

    岡本 章

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  • Fulbright Award

    2010   Fulbright  

    OKAMOTO Akira

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Research Projects

  • Quantitative Analysis of Public Policy in a Depopulating Society: From the Viewpoints of Welfare Evaluation and Future Population Levels

    Grant number:23K01350  2023.04 - 2028.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    岡本 章, 乃村 能成

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    Grant amount:\4680000 ( Direct expense: \3600000 、 Indirect expense:\1080000 )

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  • Quantative Analysis on Demographic Dynamics and Intergenerational Income-Class Mobility by an Overlapping-generations Model with Endogenous Fertility

    Grant number:20K01679  2020.04 - 2025.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    岡本 章, 乃村 能成

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    Grant amount:\4420000 ( Direct expense: \3400000 、 Indirect expense:\1020000 )

    人口減少・少子高齢化が急速に進展する日本では、経済を支える労働力人口の確保が喫緊の課題となっている。少子化対策による出生率の引き上げが望まれるが上手くいっていないのが現状であり、外国人労働者の受け入れを増やすことが現実的な選択肢の一つとなっている。日本政府は2014年、10年間で200万人の外国人労働者の受け入れを検討すると発表した。同じ200万人を受け入れるにしても1~2年で200万人を受け入れる場合と10、20年かけて少しずつ受け入れる場合とでは、経済や人口、個人の効用は変わってくる。本研究では、このような移民にかかわる問題を分析できるように、「人口内生化世代重複シミュレーションモデル」の拡張を行った。そして、総計で200万人の移民を受け入れる場合に、各年の移民の数を均等に配分し、1~2年の短期間に集中して受け入れる場合と10、20年かけて少しずつ受け入れる場合に関して、一人当たりの効用や将来の人口水準への影響について定量的な分析を行った。
    シミュレーション分析の結果、移民の受け入れ期間を9年にすると(現在世代、将来世代を含めた全ての世代について)個人が得られる効用が最大になり、効率性の点では、9年の受け入れ期間が最も望ましいとの結果が得られた。また、長期的な人口の水準については、受け入れ期間が長ければ長いほど大きくなった。この要因の一つとして、日本の人口・労働人口は今後も減少し続けていくことから、将来であればあるほど一人の移民の人口シェアが大きくなり、その貢献も大きくなることが挙げられる。移民の受け入れ期間が長ければ長いほど長期的な総人口は大きくなるが、各年の移民の数は小さいため、移民の受け入れを開始した当初は経済成長が相対的に小さくなる。反対に、1~2年の短期間に集中して移民受け入れる場合には、最初の頃の経済成長は大きいが、長期的には人口水準が小さくなり、経済成長も相対的に小さくなる。

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  • Welfare Analysis of Public Policy by an Overlapping-generations Model with Endogenous Fertility

    Grant number:15K03514  2015.04 - 2019.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    Okamoto Akira

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    Grant amount:\4550000 ( Direct expense: \3500000 、 Indirect expense:\1050000 )

    This paper quantifies the effects of the intergenerational earnings mobility in an aging and depopulating Japan on the individual welfare and the future demography. The simulation reveals that increases in intergenerational earnings mobility promote economic growth, but in the very long run, on the contrary they hinder economic growth.
    This is because the increased mobility raises the population ratio of the higher income household has lower fertility and increases the population share of workers with higher earnings ability increases. In the very long run, the negative effect of decreasing population exceeds the positive effect of the increased share of higher ability workers.

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  • Welfare Analysis of Tax and Social Security Systems in Aging and Depopulating Societies

    Grant number:23530370  2011.04 - 2015.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    OKAMOTO Akira, YOSHINARI Nomura

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    Grant amount:\5070000 ( Direct expense: \3900000 、 Indirect expense:\1170000 )

    Japan is currently facing an aging population and fewer children, and it is forecasted that this trend will continue after this. This research project has analyzed the effects of the family policy of child allowances, using an extended lifecycle simulation model with endogenous fertility. Simulation results show that the policy of increases in government child subsides is desirable from the long-run perspective because the policy can improve the welfare of all generations by appropriate fund transfers. However, the analysis also suggests that the recommended family policy is difficult to be implemented under the current Japanese voting system, which reflects the situation that is often criticized as the "Silver Democracy."

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  • Tax and Social Security Policies in Aging Societies

    Grant number:19530276  2007 - 2010

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    OKAMOTO Akira

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    Grant amount:\4420000 ( Direct expense: \3400000 、 Indirect expense:\1020000 )

    With a population that is aging faster than any other in the world, Japan faces serious public finance problems, particularly when it comes to tax and social security issues. The structural reforms are urgently needed to accommodate the impending demographic change. We looked at the Japanese tax and social security systems through a life-cycle general equilibrium simulation model. The simulation results suggest that even consumption financing of only basic pensions may not bring about a Pareto improvement, although it enlarges output of the economy by inducing capital formation.

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  • A quantitative analysis of the tax and social security systems in an aging Japan

    Grant number:15530215  2003 - 2006

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    OKAMOTO Akira

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    Grant amount:\2500000 ( Direct expense: \2500000 )

    With a population that is rapidly aging, Japan faces serious public finance problems, particularly when it comes to tax and social security issues. The structural reforms are urgently needed to accommodate the impending demographic change. We look at the Japanese tax and social security systems through a life-cycle general equilibrium simulation model. We aim to establish guidelines for fiscal reform in Japan's graying society and use such advanced modeling techniques to permit the calculation of the effects of alternative tax policies on capital accumulation and economic welfare.
    The following three main conclusions have been drawn.
    1. The simulation results show that a progressive expenditure tax stimulates much more capital accumulation than a progressive labor income tax. Thus, this new tax regime may hold the key to overcoming the large welfare loss Japan faces as its society ages under the current tax system. We also examined a desirable tax combination along the lines of the current Japanese tax and social security systems. The results suggest that an increase in the rate of tax on consumption and a decrease in the rate of tax on interest income may be a desirable tax combination under conditions of revenue neutrality.
    2. We explored a desirable public pension system in an aging Japan. The simulation results show that, if we consider a public pension program with the same scale as the current Japanese program, the highest level of social welfare is attained when a public pension system consists of only a basic pension and is financed by a consumption tax.
    3. We investigated an optimal rate of the national burden in an aging Japan. The simulation results suggest that an optimal rate for the national burden would rise as Japan ages, and may exceed 50% during a period of rapid aging of its population.

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  • 少子高齢化社会における租税・社会保障政策

    Grant number:13730064  2001 - 2002

    日本学術振興会  科学研究費助成事業  若手研究(B)

    岡本 章

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    Grant amount:\2200000 ( Direct expense: \2200000 )

    本研究の目的は、少子高齢化の急速に進展するわが国における望ましい租税・社会保障政策について、効率性および公平性の観点から定量的に検討を行うことである。分析手法として、ライフサイクル一般均衡モデルによるシミュレーション分析を用いた。
    Okamoto "Simulating Progressive Expenditure Taxation in Aging Japan" (forthcoming in Journal of Policy Models)での分析の結果、新たな税形態である累進支出税を導入することにより、所得税中心の現行の税制度の下で生じるであろう大幅な社会厚生の損失を克服できる可能性があることが示された。すなわち、所得から支出への課税ベースの移行は資本蓄積を促進し、また支出税に累進性をもたせることによって所得再分配を効率的に実施できることが示された。
    この結論を踏まえて、Okamoto and Tachibanaki(2002) "Integration of Tax and Social Security Systems : On the Financing Methods of a Public Pension Scheme in a Pay-as-You-Go System" (in Ihori and Tachibanaki ed.,Social Security Reform in Advanced Countries, Routledge)では、具体的にわが国の租税と年金制度の改革の方向性について検討を行った。現在公的年金制度の基礎年金部分の3分の1が税収からのトランスファーによって賄われているが、これを2分の1に増加させる方向で議論が行われている。分析の結果、政府のこの方針が支持されることとなった。今後さらに租税と年金制度の統合を推進し、究極的には累進支出税で全収入を賄うことが効率性および公平性の点で最適であるとの結果が得られた。

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  • ワークショップ「縮小社会への不適応の問題」への参加

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  • 人口減少・少子高齢化と日本の財政

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    岡山大学  経済学部公開講座「経済の課題とパースペクティブ」  2007.6.23

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