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HPを更新
HPを更新
日本経済新聞にコメントが掲載されました
日本経済新聞にコメントが掲載されました
NHKから国民生活基礎調査に関するインタビューを受けました
NHKで国民生活基礎調査に関するインタビューを受けました。
「マクロ経済学で見る格差」
日本経済新聞にて連載が始まります
Note TakingとPKMアプリ
Capacities
FFJ-Banque de France Workshop
FFJ-Banque de France Workshop
大学院の指導教員について
大学院で私を指導教員に選びたい人は必ず以下を読んでください
数値計算初心者にPythonよりJuliaをお勧めする理由
Juliaの長所
番外編:仕事場環境を考える
仕事場環境にこだわる
その他:音楽
その他の生産性を高めてくれるアプリ
メールアプリ
メーラー
ブラウザ
今さらブラウザ?
カレンダー
カレンダーアプリ
To DoとGTD(Getting Things Done)
To DoとGTD
手書きアプリ
ペーパーレス化に関する個人的な意見
生産性向上のためのアプリ:情報を一箇所にまとめる
Notion
生産性を高めたい
生産性を高めるための環境作り
(マクロ)経済学を自学自習する
経済学を独学する
アイコンを変更
HPのメインアイコンを変更
備忘録:MacBook Airに引っ越し
MacBook Airを新規購入
HDDの中身を整理する➔学部生向け
PCの中身を整理してください
プログラミング技術の本を読んでみよう
プログラミングの技術書を読んでみる
Visual Studio Codeをインストールしよう
VS Code
Markdownって知ってる?
ドキュメント作成
絶対に覚えてほしいショートカット7選
最近の学生はPCを使えなくなっているらしい
論文・レポートを書く:学部生向け
論文・レポートを書く
テキストエディタをもっと活用する
テキストエディタをもっと使おう
生産性を高める(かもしれない)アプリ
自分のPC・スマホにインストール済みのアプリ
Jupyterに残った古いカーネルを消す
Juliaをアップデート後のJupyterの更新について
Julia関連の書籍
Webだけで十分?
GitHub Pagesに引っ越し
なぜ引っ越しをしたのか?
computation
マクロ経済学講義@METI
講義スライド & Pythonコード一式
チュートリアルセッション@日本経済学会 2021年度春季大会
2021年度日本経済学会 春季大会の企画セッションで使用した資料一式
定量的マクロ経済学と数値計算
大学院生・学部上級生向けの教科書:好評発売中!
publications
Nonlinear Income Variance Profile and Consumption Inequality over the Life Cycle
Abstract
In contrast to many other countries, consumption inequalities in Japan are not constant over household age but increase from around middle age—a fact first highlighted by Ohtake and Saito (1998). Given this information, we examine whether this phenomenon is consistent with the standard precautionary saving model developed by Carroll (1997). Specifically, we investigate; (1) the degree of age dependence of idiosyncratic income risks; and (2) the importance of age dependence for the evolution of inequalities in consumption predicted by the household model of Carroll (1997). We find a strong age dependence of income risks, which creates a nonlinear age–variance profile of income, and the standard precautionary saving model is consistent with the observed consumption inequalities as long as we take the nonlinearity in age–variance profiles of income into account.
Abe, Naohito and Tomoaki Yamada (2009): "Nonlinear Income Variance Profile and Consumption Inequality over the Life Cycle," Journal of the Japanese and International Economies, Vol. 23, Issue 3, pp. 344-366, 2009.
Persistence of Income Shocks and Consumption Inequality: A Case in Japan
Abstract
The present study investigate the relationship between the persistence of uninsurable income shocks and consumption inequality over a household's life cycle in Japan. Using a life cycle model with incomplete asset markets and calibrated parameters for the Japanese economy, we quantitatively show that moderate persistence of shocks generate a nonlinear consumption inequality profile over the life cycle. The moderate persistence of shocks well replicates the pattern of consumption inequality in Japan.
Yamada, Tomoaki (2009): "Persistence of Income Shocks and Consumption Inequality: A Case in Japan," Economics Bulletin, Vol. 29, No. 4 pp. 2816-2825, 2009.
On the Intergenerational Sharing of Cohort-Specific Shocks on Permanent Income
Abstract
This paper investigates the intergenerational sharing of shocks on the permanent income of new entry cohorts when prior-to-entry markets are missing. When Lucas trees are traded among generations, procyclical cohort-specific shocks are shared partially via the movement of asset prices; cohorts with lower endowments may benefit more from asset pricing dynamics than cohorts with higher endowments. Given a reasonable set of parameters concerning the Japanese labor market, the evaluated welfare loss ranges from 1% to 3% in terms of the certainty equivalence consumption level. The first-best outcome may be achieved by either a combination of subsidies and taxes or the introduction of prior-to-entry markets.
Miyazaki, Kenji, Makoto Saito and Tomoaki Yamada (2010): "On the Intergenerational Sharing of Cohort-Specific Shocks on Permanent Income," Macroeconomic Dynamics, Vol. 14, No. 1, pp. 93-118, 2010.
A Politically Feasible Social Security Reform with a Two-Tier Structure
Abstract
This paper investigates the welfare implications and political feasibility of social security reforms with a two-tier structure in Japan. We evaluate social security reforms from two points of view; (i) the ex-ante expected value of future generations, and (ii) whether current generations prefer reform to the status-quo system, which we call political feasibility. To evaluate the reforms, we use a large-scale overlapping generations model with idiosyncratic income risk and a two-tier structure. The first tier guarantees a basic pension and the second tier consists of the earnings-related part. Calibrating the parameters of the model to the Japanese economy, we compute the transition path and the two welfare criteria. We find that, given the two-tier structure in Japan, an increase in the basic pension and the abolition of the earnings-related part of the social security system improve the welfare of future generations, and ensures political feasibility when a consumption tax is the source of revenue.
Yamada, Tomoaki (2011): "A Politically Feasible Social Security Reform with a Two-Tier Structure," Journal of the Japanese and International Economies, Vol. 25, Issue 3, pp. 199-224, 2011.
Income Risk, Macroeconomic and Demographic Change and Economic Inequality in Japan
Abstract
Using an OLG model with heterogeneous households, we investigate the relationship among income risk, macroeconomic and demographic changes, and economic inequality between 1980 and 2000 in Japan. By decomposing the primary factors in earnings and consumption inequality into macroeconomic variables and the demographic variable, we find that our model replicates the evolution of economic inequality in Japan. By performing counterfactual simulations, we demonstrate that two factors—changes in time-varying macroeconomic factors and the unexpected decline in the total factor productivity growth rate—played important roles in the increase in earnings and consumption inequality in the 1990s.
Yamada, Tomoaki (2012): "Income Risk, Macroeconomic and Demographic Change and Economic Inequality in Japan," Journal of Economic Dynamics and Control, Vol. 36, pp. 63-84, 2012.
Wage, Income and Consumption Inequality in Japan, 1981-2008: from Boom to Lost Decades
Abstract
In this paper we document the main features of the distributions of wages, earnings, consumption and wealth in Japan since the early 1980s using four main data sources; the Basic Survey on Wage Structure (BSWS), the Family Income and Expenditure Survey (FIES), the National Survey of Family Income and Expenditure (NSFIE) and the Japanese Panel Survey of Consumers (JPSC). We present an empirical analysis of inequality that specifically considers the path from individual wages and earnings, to household earnings, after-tax income, and finally consumption. We find that household earnings inequality rose substantially over this period. This rise is made up of two distinct episodes; from 1981 to 1996 all incomes rose, but they rose faster at higher percentiles; from 1996 to 2008 incomes above the 50th percentile remained flat but they fell at and below the 50th percentile. Inequality in disposable income and in consumption also rose over this period but to a lesser extent, suggesting taxes and transfers as well as insurance channels available to households helped to insulate household consumption from shocks to wages. We find the same pattern in inequality trends when we look over the life cycle of households as we do over time in the economy. Additionally we find that there are notable differences in the inequality trends for wages and hours between men and women over this period.
Lise, Jeremy, Nao Sudo, Michio Suzuki, Ken Yamada, Tomoaki Yamada (2014): "Wage, Income and Consumption Inequality in Japan, 1981-2008: from Boom to Lost Decades," Review of Economic Dynamics, Vol. 17, pp. 582-612, 2014.
Achieving Fiscal Balance in Japan
Abstract
Japan is aging and has the highest government debt-to-output ratio among advanced economies. In this article, we build a micro data-based, large-scale overlapping generations model for Japan in which individuals differ in age, gender, employment type, income, and asset holdings, and incorporate the Japanese pension rules. Using existing pension law, current fiscal policy, and medium variants of demographic projections, we produce future paths for government expenditures and tax revenues, with implications for government debt and the public pension fund. Additional pension reform, a higher consumption tax, and higher female labor force participation help achieve fiscal stability.
Imrohoroglu, Selahattin, Sagiri Kitao and Tomoaki Yamada (2016): "Achieving Fiscal Balance in Japan," International Economic Review, Vol. 57, No. 1, pp. 117-154, 2016.
Can Guest Workers Solve Japan’s Fiscal Problems?
Abstract
The labor force in Japan is projected to fall from 64 million in 2014 to 20 million in 2100, signaling unprecedented tax/transfer adjustments to achieve fiscal sustainability. In this paper, we develop a quantitative overlapping generations model to measure the impact of guest worker programs in Japan. Against a baseline general equilibrium transition in which the consumption tax adjusts to achieve fiscal sustainability, we compute alternative transitions with guest worker programs. Depending on the size and skill distribution of guest workers, these programs may mitigate Japan's fiscal imbalance problem with a relatively manageable increase in the consumption tax.
Imrohoroglu, Selahattin, Sagiri Kitao and Tomoaki Yamada (2017): "Can Guest Workers Solve Japans Fiscal Problems?," Economic Inquiry, Vol. 55, No. 3, pp.1287-1307, 2017.
Population Aging, Health Care and Fiscal Policy Reform: The Challenges for Japan
Abstract
We construct a transition analysis based on a general equilibrium life-cycle model to investigate the effects of aging, and we evaluate various policy alternatives designed to lessen the negative influence of aging. In particular, we analyze reforms of insurance benefits and tax financing tools that were recently the focus of a great amount of attention and debate in Japan because of the tense financial situation there. We show that although the potential reforms improve the welfare of future generations, the political implementation of such reforms is difficult because of the large welfare costs for the current population. Our analysis suggests that a gradual reform with an intergenerational redistribution will be more politically implementable than an immediate reform.
Hsu, Minchung and Tomoaki Yamada (2019): "Population Aging, Health Care and Fiscal Policy Reform: The Challenges for Japan," Journal of the Economics of Ageing, Vol. 121, Issue 2, pp. 547-588, 2019
Fiscal Sustainability in Japan: What to Tackle
Abstract
Japan leads all advanced economies in terms of aging and has the highest debt to GDP ratio. The public pension, medical and long-term care (LTC) expenditures are projected to far outpace revenues and create significant fiscal burdens. In this paper, we develop a detailed overlapping generations model that incorporates the social insurance programs in detail, use most recent estimates from Japanese micro data and government demographic projections to discipline the earnings and labor supply profiles of heterogeneous agents and their cohort shares, and simulate future paths of fiscal and macroeconomic indicators. Our numerical results suggest that absent any change in current policies, Japan will continue to run large pension, public health, LTC, and basic deficits and the debt to GDP ratio will continue to reach unprecedented highs, with interest payments on the debt becoming larger and larger. Although no single policy tool can address fiscal consolidation, a combination of policies is found to achieve sustainability; raise the retirement age to 67, cut pensions by 10%; raise copays of health and LTC insurances to 20%, and find policies to propel female employment and earnings to the levels of their male counterparts, and increase consumption tax rate to 15%. Under these changes, the debt to output ratio in 2050 would be lower than that in 2020.
Imrohoroglu, Selahattin, Sagiri Kitao and Tomoaki Yamada (2019): "Fiscal Sustainability in Japan: What to Tackle," Journal of the Economics of Ageing, Vol. 14.
Foreign Workers, Skill Premium and Fiscal Sustainability in Japan
Abstract
Japan faces rapid and severe demographic aging and rising fiscal deficits due to increasing expenditures and shrinking tax revenues. This paper studies how an inflow or an outflow of foreign workers affects projections of macroeconomic and fiscal variables. We show that foreign workers help slow down a decline in labor force and mitigate fiscal pressures, but effects are not large enough to wipe away concerns even under a very optimistic scenario. We also evaluate effects of foreign workers on skill-specific wages in Japan and welfare consequences across heterogeneous individuals. A rapid rise in the relative size of high-skilled labor force in Japan will give strong downward pressure on skill premium and an arrival of foreign workers is shown to have large differential effects on skill prices and the trend of wage inequality, depending on their size and skill composition.
Kitao, Sagiri and Tomoaki Yamada (2021). "Foreign Workers, Skill Premium and Fiscal Sustainability in Japan." Economic Analysis, Vol. 202, pp. 220-243.
The Time Trend and Life-cycle Profiles of Consumption
Abstract
This paper analyzes the time trend of household consumption in Japan between 1981 and 2020, using microdata from the Family Income and Expenditure Survey (FIES). We examine how the trends in the levels, shares, and growth of consumption vary across categories of consumption, items, and age groups, and assess changes in consumption inequality over time. Our analysis shows that consumption inequality mildly increased, driven primarily by the trend of service consumption and a shift in the age distribution. Additionally, we estimate the life-cycle profiles of consumption and find that the age component of total consumption follows a standard hump-shaped pattern, but varies significantly across goods and service categories and item groups. Finally, using the estimated age profiles of different consumption items, we project how aggregate consumption and its composition may evolve as Japan’s population ages in the coming decades.
Kitao, Sagiri and Tomoaki Yamada (2024). "The Time Trend and Life-cycle Profiles of Consumption." Review of Economics of the Household, Vol. 23, pp. 71-111.
Preface to the JER Spesial Issue on Hetergeneity and Mecroeconomics
Mukoyama, Toshihiko, Makoto Nakajima and Tomoaki Yamada (2025): "Preface to the JER Spesial Issue on Hetergeneity and Mecroeconomics," Japanese Economic Review, Vol. 75, pp. 227–229.
Earnings, Income, and Wealth Inequality in Japan: A Long‑term Perspective, 1984–2019
Abstract
This study examines trends in earnings, income and wealth inequality among households in Japan from 1984 to 2019. Our findings reveal that inequality in all three domains has increased over the last decades, but due to different underlying factors. The rise in earnings and income inequality is primarily driven by demographic aging, with an increasing proportion of elderly households who typically exhibit higher inequality levels. The growth in wealth inequality is evident not only in the overall population but is particularly pronounced among the young. This trend is largely attributed to a significant rise in the number of households that possess extremely low wealth. Key factors contributing to inequality trends in Japan include aging demographics, shifts in household structure, and major macroeconomic developments such as the financial bubble period and the prolonged economic slow-down that followed.
Kitao, Sagiri and Tomoaki Yamada (2025). "Earnings, Income, and Wealth Inequality in Japan: A Long‑term Perspective, 1984–2019." Japanese Economic Review, Vol. 75, pp. 231–283.
Macroeconomic and Fiscal Implications of Changes in the Labor Share under Population Aging in Japan
Abstract
This study examines how declining labor share affects macroeconomic outcomes and fiscal sustainability in Japan—the country with the most advanced population aging globally. While previous research has documented the global trend of declining labor share, its implications for fiscal policy in aging societies remain underexplored. Using a life-cycle general equilibrium model in the Auerbach–Kotlikoff tradition, we calibrate parameters to match Japan’s economic and demographic characteristics, incorporating country-specific institutions such as public pension, health insurance, and long-term care systems. Our analysis reveals that when capital share increases by 3 percentage points between 2025–2060, it generates fiscal relief equivalent to approximately 3 percentage points in consumption tax by 2070 through enhanced capital accumulation. More significantly, this declining labor share amplifies the efficacy of pension reforms, potentially yielding savings equivalent to over 12 percentage points in consumption tax. Our findings suggest that declining labor share, when coupled with appropriate policy reforms, may benefit fiscal sustainability in rapidly aging societies with high public debt.
Yamada, Tomoaki (2025): "Macroeconomic and Fiscal Implications of Changes in the Labor Share under Population Aging in Japan," Journal of the Economics of Ageing.
teaching
過去の様々な講義
出張講義・オープンキャンパスなど, 明治大学, 2021
過去のオムニバス形式の講義資料を公開
経済政策論特論
通年(大学院), 9:00-10:40, 2022
大学院向け講義資料
商学専門演習
通年, 15:10-17:00(月曜日)@駿河台, 15:10-17:00(金曜日)@和泉, 2025
2026年度のゼミ募集はありません
経済学B
秋学期, メディア授業, 2025
経済政策論B
秋学期, 月曜日:13:30-15:10@1114教室, 2025
経済政策論A
春学期, 月曜日:13:30-15:10@1114教室, 2025
