Details of a Researcher

Papers - NOMURA Koji

Division display 1 - 20 of about 138 ／ All the affair displays >>

"Measuring Real Energy Price Gaps: The Real PLI Framework for Competitiveness Monitoring"

Koji Nomura and Sho Inaba

Preprints.org 2025.11

Research paper (conference, symposium, etc.), Joint Work, Corresponding author

This study addresses two critical gaps in international energy cost competitiveness. The first is a frequency gap: conventional indicators such as the Real Unit Energy Cost (RUEC) are typically published with delays of 2–5 years, limiting their usefulness for timely policy evaluation. Here, both RUEC and the Real Price Level Index for energy (Real PLI)—the ratio of the Purchasing Power Parity (PPP) for energy to that for GDP—are measured with only a 2–3 month lag for nine countries—four in Asia, four in Europe, and the U.S. The second is a competitiveness gap that calls for policy re-sponses. Real PLIs indicate that the energy price disadvantages of Japan, Korea, France, Germany, Italy, and the UK have widened from about 1.8–2.9 times the U.S. level before the pandemic to 2.2–3.3 times by Q2 2025, with gaps also increasing rela-tive to China and India. Once country-specific thresholds are exceeded, output in en-ergy-intensive and trade-exposed (EITE) industries tends to contract disproportion-ately. These findings highlight that sustainable transitions require not only interna-tionally differentiated burden-sharing but also structural reforms to avoid persistent widening of energy price gaps. The Real PLI framework offers a timely competitiveness indicator and early-warning tool, signaling when growing asymmetries may under-mine policy feasibility.

Access to Document (DOI)

"Productivity Dynamics in the Maldives: A First Outlook Based on the Maldivian Productivity Accounts, 1970–2023, with Comparisons to SAARC and Fiji"

Koji Nomura

(United Nations Economic and Social Commission for Asia and the Pacific) 2025.10

Research paper (other academic), Single Work

This report presents the first comprehensive productivity analysis for the Maldives based on the newly developed Maldivian Productivity Accounts, covering the period 1970–2023 and including cross-country comparisons with SAARC members and Fiji. The results show that sustained economic growth of 5–7% per year from 1970 to 2019 was supported by a nearly thirtyfold expansion of capital input and a twentyfold increase in labor input, including migrant workers. However, improvements in TFP have remained close to zero or even negative. The capital–output ratio reached 5.3 in 2023—the highest in the SAARC region—reflecting low investment efficiency and possible overaccumulation. Transitioning from quantity-driven to efficiency-based growth is essential for the Maldives to achieve sustainable productivity and long-term economic resilience.

"Bhutan’s Productivity Trends, 1990–2023: Findings from Bhutanese Productivity Account 2025"

Koji Nomura

(United Nations Economic and Social Commission for Asia and the Pacific) 2025.08

Research paper (other academic), Single Work

The Bhutanese Productivity Account 2025 provides updated productivity estimates for 1990–2023, developed jointly by the DMDF and Keio University. While Bhutan’s hydropower-led growth model has achieved rapid labor productivity gains, the report reveals persistent stagnation in total factor productivity (TFP) and a steep decline in capital productivity. Capital input accounted for nearly 84% of GDP growth during this period, yet TFP contributed negatively on average, underscoring a pattern of capital accumulation without corresponding efficiency gains. The electricity sector, despite significant investment, saw long-term declines in TFP due to rising construction costs and limited output growth. Moreover, positive spillover effects to non-electricity industries have been limited, with manufacturing showing only modest improvements. International comparisons highlight a widening TFP growth gap between Bhutan and countries like India. Growing electricity demand from data centers and rising import dependency pose further challenges. The report emphasizes that Bhutan’s growth cannot be fully understood through labor productivity alone. To achieve sustainable, high-quality growth aligned with the 13th Five Year Plan, Bhutan must improve productivity in non-electricity sectors through investment in innovation, human capital, and structural reform, while addressing electricity supply constraints and maintaining macroeconomic resilience.

"Bhutan’s Productivity Stagnation: Hydropower and Beyond"

Koji Nomura

Hydropower-Led Economic Growth in Bhutan (Springer) 207 - 237 2025.05

Part of collection (book), Single Work

This chapter analyzes Bhutan’s productivity dynamics from 1990 to 2022, focusing on industry-level and aggregate total factor productivity (TFP) and capital and labor productivity. Hydropower plays a pivotal role in shaping Bhutan’s economic structure, driving substantial gains in labor productivity, especially after the commissioning of major plants. However, these gains have been offset by a capital productivity decline, leading to overall TFP growth stagnation. Despite hydropower’s importance in Bhutan’s economic expansion, its long-term contribution to TFP remains limited due to the capital-intensive nature of large-scale projects, which strains capital efficiency. The chapter also highlights productivity patterns in the non-electricity sector, where labor productivity gains are more prominent, but TFP improvements remain minimal. These findings emphasize the challenges of sustaining productivity growth in Bhutan’s hydropower-led economy and point to the risks of over-reliance on a single sector. A dual strategy is necessary: fostering internationally competitive industries that leverage hydropower while ensuring affordable and stable electricity supply to meet the expanding domestic demand. This approach is essential for achieving long-term sustainable economic growth.

Access to Document (DOI)

"Measuring Capital Accumulation in Bhutan"

Koji Nomura

Hydropower-Led Economic Growth in Bhutan (Springer) 171 - 205 2025.05

Part of collection (book), Single Work

This chapter constructs industry-level capital inputs for Bhutan from 1990 to 2022, addressing the absence of a capital stock account in the Bhutanese System of National Accounts (BTSNA). It develops time-series investment and stock matrices to create industry-specific, quality-adjusted capital inputs. A key methodological adjustment is the shift of hydropower investments from a work-in-progress basis to an installed basis, ensuring that only fully operational assets are included in capital services. Large-scale hydropower projects often experience time lags of over 10 years from construction to operation, so this adjustment is crucial for accurate productivity assessment. As of early 2022, Bhutan’s nominal net capital stock is estimated at Nu 905 billion, roughly four times its GDP—the highest ratio in South Asia. Despite being one of the most capital-intensive economies in the region since the 1990s, Bhutan’s capital inputs continued to expand rapidly, averaging 9.5% growth per year between 1990 and 2022. This rapid growth occurred not only in the electricity sector but also across non-electricity industries, with an even faster accumulation after the democratic transition in 2008. While data limitations remain, this study establishes a vital framework for understanding Bhutan’s capital dynamics and lays the foundation for future refinements.

Access to Document (DOI)

"Bhutan’s Aggregate Output: A Review"

Koji Nomura

Hydropower-Led Economic Growth in Bhutan (Springer) 15 - 51 2025.05

Part of collection (book), Single Work

This chapter comprehensively reviews Bhutan’s aggregate outputs from 1990 to 2022, focusing on expenditure-side GDP and hydropower-led growth. It reconciles multiple versions of the Bhutanese System of National Accounts (BTSNAs) to address inconsistencies and construct reliable long-term series for key indicators such as gross fixed capital formation (GFCF), exports, and imports. A key concern in constructing industry-level productivity accounts is investment, which in Bhutan is closely tied to imports. Ensuring alignment between final demand by product and investment measurement is crucial for accurate productivity analysis. The chapter highlights the significant role of hydropower in driving Bhutan’s nominal GDP growth, accounting for 34.0% of growth from 1990 to 2008 and 22.1% from 2008 to 2022. Bhutan’s high share of investment in GDP, which surpasses that of other South Asian nations and often exceeds China’s, is noteworthy. However, the capital-intensive model raises concerns about resource allocation efficiency and productivity improvements. This chapter lays the groundwork for a deeper understanding of Bhutan’s economic trajectory and future challenges, which will be explored in greater detail in the following chapters.

Access to Document (DOI)

"Reevaluating Industry Origins of Bhutan’s Economic Growth"

Koji Nomura

Hydropower-Led Economic Growth in Bhutan (Springer) 53 - 132 2025.05

Part of collection (book), Single Work

This chapter develops time-series Supply and Use Tables (SUTs) for Bhutan from 1990 to 2022, addressing challenges posed by data gaps and inconsistencies across various versions of the Bhutanese System of National Accounts (BTSNA). It emphasizes the importance of adopting consistent methodologies for assessing industry and product outputs, particularly in sectors like electricity, where pricing complexities and measurement issues are prominent. The official estimates, which are based on fixed-weight Laspeyres indices, tend to underestimate real value-added growth. By applying double deflation and chain indices based on the time-series SUTs constructed in this chapter, real GDP growth estimates for the post-democratization period (2008–2022) are revised, revealing an average revised real growth rate of 5.5%, 0.74 percentage points higher than the official figs. A notable shift in growth drivers is also identified: hydropower’s contribution to real growth decreased from 27.2% (1990–2008) to 14.1% (2008–2022). The manufacturing sector’s contribution also halved, suggesting potential signs of “Dutch disease.” The findings emphasize the need for further refinement in data to strengthen the analysis and lay the groundwork for a detailed productivity study in subsequent chapters.

Access to Document (DOI)

"Labor Input and Quality Evolution in Bhutan"

Koji Nomura

Hydropower-Led Economic Growth in Bhutan (Springer) 133 - 170 2025.05

Part of collection (book), Single Work

This chapter compiles comprehensive labor data for Bhutan from 1990 to 2022, addressing the absence of consistent time-series estimates for the compensation of employees (COE) in the Bhutanese System of National Accounts. By constructing quality-adjusted labor input (QALI) across industries, the study identifies significant shifts in labor dynamics, particularly following democratization. Bhutan’s labor share remained consistently lower than India’s, experiencing a decline until the late 2000s, followed by an upward trend after the transition. From 2008 to 2022, aggregate hours worked grew modestly (0.14% annually), while labor input expanded by 3.13% annually, largely driven by a 2.99% annual improvement in labor quality. This improvement was primarily due to educational attainment, which accounted for 84.3% of the total gain. The chapter also emphasizes the limited role of the hydropower sector in direct employment despite its economic significance. Although data accuracy varies, this chapter provides a critical foundation for understanding Bhutan’s labor market dynamics and highlights challenges related to labor mismatches and the broader implications for sustainable development.

Access to Document (DOI)

"Bhutan’s Hydropower-Led Economic Growth"

Koji Nomura

Hydropower-Led Economic Growth in Bhutan (Springer) 1 - 13 2025.05

Part of collection (book), Single Work

This chapter provides an overview of Bhutan’s hydropower-led economic growth, context, and challenges. The study aims to construct an industry-level productivity account from 1990 to 2022, analyzing hydropower’s impact on economic growth and resource allocation. Bhutan’s limited data availability and quality present challenges for developing an accurate industry-level productivity account, but also provide opportunities to adopt rigorous methods to address measurement issues. Although further analysis is necessary, the estimates for the overall economy and the two key sectors—electricity and non-electricity—are considered sufficiently reliable. Key findings include Bhutan’s exceptionally high investment ratio compared to other South Asian countries, the significant contribution of hydropower to economic growth, and stagnation in total factor productivity (TFP) despite rapid labor productivity growth. These insights highlight the complexities of Bhutan’s development model. The chapter concludes by outlining the book’s structure and guiding readers through the following detailed analyses. By offering nuanced insights into Bhutan’s economic trajectory, the study is a foundation for future research and informed policymaking.

Access to Document (DOI)

"Estimating Flexible Functional Forms using Macroeconomic Data"

W. Erwin Diewert, Koji Nomura, and Chihiro Shimizu

Empirical Economics (Springer) 2025.03

Research paper (scientific journal), Joint Work, ISSN 03777332

The paper estimates a flexible functional form for a joint cost function using US aggregate data for the years 1970–2022. There are four outputs (consumption, government,investment and exports) and six inputs (imports, labour, machinery and equipment services, structure services, other capital services and land services). Curvature conditions on the joint cost function are imposed without destroying the flexibility of the functional form. Various elasticities of supply and demand are estimated along with technical progress bias terms for each input. When using aggregate time series data based on the System of National Accounts, the paper shows that it is probably better to estimate a joint cost function rather than a gross output function or a GDP function. The paper also shows that assuming that an aggregate production function has constant elasticities of substitution is not appropriate for the US. Finally, the importance of including land as an aggregate input is stressed.

Access to Document (DOI)

"Energy Price Surge and Widening Real Price Differentials in the Post-Pandemic Era: A Comparative Analysis of Seven Major Countries" (in Japanese)

Koji Nomura and Sho Inaba

KEO Discussion Paper (Keio Economic Observatory, Keio University) ( 185 ) 1 - 44 2025.03

Research paper (bulletin of university, research institution), Joint Work

This paper aims to measure and analyze the changes in international price differentials in comprehensive final energy consumption accompanying the recent energy price surges across seven major countries (Japan, China, South Korea, the U.S., the UK, Germany, and France). For measuring international price differentials, we employ not only the Price Level Index (PLI) for energy but also the Real Price Level Index (Real PLI), which accounts for the price differentials of outputs produced using energy inputs. Real PLI is an indicator independent of exchange rate fluctuations. Our preliminary estimates from January 2015 to December 2024 reveal the following observations. First, the US has maintained an overwhelming advantage in real energy price differentials even before the pandemic, with the other six countries bearing energy price burdens 1.8 to 2.2 times higher than the U.S. Second, while energy prices surged similarly across major countries during the global economic recovery from the pandemic beginning in early 2021, the real price differentials relative to the U.S. also expanded in five countries (excluding China) during the same period. These differentials widened to 2.3–2.7 times at their peak and continue to persist at 2.3–2.5 times the U.S. level. Third, China has significantly suppressed energy price increases during this period, particularly for coal and electricity, maintaining its price differential with the U.S. at nearly the pre-pandemic level. As the second Trump administration pursues energy dominance by expanding the use of inexpensive fossil fuels, further widening of energy price differentials and loss of international competitiveness are inevitable if Japan and European countries continue their current decarbonization policies. The Japanese economy should consider shifting toward policies aimed at reducing these international price differentials.

Access to Document (DOI)

"How should companies face the GX (Green Transformation)?" (in Japanese)

Koji Nomura

SBI Research Review (SBI Financial and Economic Research Institute) 7 24 - 36 2025.02

Research paper (bulletin of university, research institution), Single Work

政府はGX（グリーントランスフォーメーション）によって産業競争力の強化を目指すが、その実現のための前提条件は満たされていない。現在、脱炭素技術は依然として高コストのままであり、主要国間の温室効果ガス排出削減の負担格差はさらに拡大しようとしている。この四半世紀のグローバルなサプライチェーンの深化の基底には、削減負担の大きい日本や欧州から負担の小さい中国などへ生産移転が進み、世界全体のCO2排出量は増加する、カーボンリーケージ（炭素の漏れ）が存在していた。2010年代後半からは先進国の脱炭素政策の加速により、弊害はエネルギー多消費製造業に拡大している。GXの創出するグリーン需要は一部の企業に一時的な恩恵を与えるが、持続的な実需とはなりにくい。政策創出需要が減退すれば、日本はさらなる空洞化とともに、高コスト技術導入による生産性低下が不可避となる。脱炭素政策からの転換に備え、企業はバランスのある経営戦略が求められる。

"Indirect Steel Trade in the Postwar Japanese Economy" (in Japanese)

Koji Nomura

KEO Discussion Paper (Keio Economic Observatory, Keio University) ( 184 ) 1 - 28 2025.02

Research paper (bulletin of university, research institution), Single Work

Since the late 2010s, when the signs of a full-scale acceleration of global decarbonization policies began to emerge, steel production in Japan and Germany has declined almost linearly. While this decline is generally attributed to weak domestic demand, understanding changes in domestic demand within the steel industry, which primarily produces intermediate goods, requires identifying the sources of final demand. This study examines recent trends in steel production decline while measuring structural changes in Japan's direct steel trade and indirect trade through downstream products in the postwar economy.
In contemporary Japan, trends in domestic steel demand are heavily influenced by changes in indirect exports and imports, which are not readily observable in conventional statistics. Since the late 1980s, Japan’s indirect exports of steel have exceeded its direct exports. Additionally, the effective import dependence of steel (the sum of direct and indirect imports) has consistently increased since the late 1970s. Until around 1990, this rise was driven by an expansion in direct imports, whereas since the late 1990s, indirect imports have played a more significant role. If the acceleration of decarbonization policies further facilitates the offshore production of downstream products such as automobiles and machinery, the contraction of indirect steel exports and the expansion of indirect imports may lead to a self-reinforcing cycle of deindustrialization, exacerbating the decline in domestic production. Without considering indirect trade, such production decline risks being misinterpreted as merely a consequence of weak domestic demand.

Access to Document (DOI)

"Recent Steel Production Decline in Japan: The Interactive Effects of Carbon Neutrality Policy and Production Relocation" (in Japanese)

Koji Nomura

Economic Statistics Research (Keizai Sangyo Toukei Kyokai) 52 ( Ⅲ ) 1 - 22 2024.12

Research paper (bulletin of university, research institution), Single Work

本稿は、2018年末以降から現在まで続く日本の鉄鋼生産の急激な減退について、直接輸出入と下流製品に組み込まれる間接輸出入の両面から分析している。そうした生産減退は、欧州や日本を中心に脱炭素政策（カーボンニュートラル政策）が強化され、排出削減が困難であるという技術制約のある鉄鋼業においても従来以上の取り組みが求められるようになったdeep decarbonizationの模索・推進期とおおむね一致している。直近における鉄鋼の構造変化を把握する資料の利用には制約があるものの、近年の生産減退は、海外への生産移転が消極的に同意する環境規制と環境規制の強化が促す生産移転という、意図せざる相互作用とその循環構造によると評価される。現実を直視しない脱炭素政策の加速は、エネルギー多消費的な素材産業にこそ強みを持つ日本経済の産業基盤に対し深刻な影響を及ぼしている。

"Development of Industry-Level Productivity Account in Bhutan, 1990–2022"

Koji Nomura

(United Nations Development Programme) 2024.09

Research paper (conference, symposium, etc.), Single Work

This study constructs an industry-level productivity account for Bhutan's economy from 1990 to 2022, focusing on the impacts of hydropower development on economic growth and resource allocation efficiency. The analysis reveals that while hydropower has been the primary driver of Bhutan's economic growth, its contribution declined significantly post-democratization. Despite maintaining the region's highest capital investment, the economy shows a striking dichotomy between high labor productivity and low capital productivity, indicating fundamental limitations in Bhutan's hydropower-led development strategy.

"Estimating Flexible Functional Forms using Macroeconomic Data"

W. Erwin Diewert, Koji Nomura, and Chihiro Shimizu

TCER Working Paper Series (Tokyo Center for Economic Research) ( E-206 ) 2024.04

Research paper (bulletin of university, research institution), Joint Work

The paper estimates a flexible functional form for a joint cost function using US aggregate data for the years 1970-2022. There are four outputs (consumption, government, investment and exports) and six inputs (imports, labour, machinery and equipment services, structure services, other capital services and land services). Curvature conditions on the joint cost function are imposed without destroying the flexibility of the functional form. Various elasticities of supply and demand are estimated along with technical progress bias terms for each input. When using aggregate time series data based on the System of National Accounts, the paper shows that it is probably better to estimate a joint cost function rather than a gross output function or a GDP function. The paper also shows that assuming that an aggregate production function has constant elasticities of substitution is not appropriate for the US. Finally, the importance of including land as an aggregate input is stressed.

"Post-Pandemic Surges of Real Unit Energy Costs in Eight Industrialized Countries"

Koji Nomura and Sho Inaba

RCGW Discussion Paper (Research Center on Global Warming, Develpment Bank of Japan) ( 70 ) 2024.03

Research paper (bulletin of university, research institution), Joint Work, Lead author, Last author, Corresponding author

This paper develops a high-frequency indicator to assess real price and cost differentials for energy use across eight industrialized countries: China, France, Germany, Italy, Japan, South Korea, the UK, and the U.S. The study assesses the overall energy cost burden using the real price level index (PLI) and the real unit energy cost (RUEC). The real PLI, unaffected by exchange rate fluctuations, provides a stable measure of real energy price differentials, while the RUEC indicates the challenges facing the energy transition. An analysis of RUEC trends from the first quarter of 2015 to the fourth quarter of 2023 highlights a substantial post-pandemic surge, particularly evident in Germany and Italy, where levels spiked by about 80% compared to pre-pandemic periods. This surge in Germany has coincided with a 20% decline in output within energy-intensive manufacturing by the end of 2023. Asian countries, on the other hand, managed to curb the post-pandemic RUEC surge to less than half of this level through energy subsidies and government interventions. Nonetheless, the higher RUEC levels in China and South Korea underscore the formidable challenges they encounter in propelling their energy transition initiatives forward. In Japan, about half of the limitations on the RUEC surge are attributed to reduced energy consumption resulting from the hollowing out of its industrial sector. Without a fundamental reevaluation of energy policies to ensure economic growth, the current path of the energy transition remains precarious.

"Improving the SNA: Alternative Measures of Output, Input, Income, and Productivity"

W. Erwin Diewert, Koji Nomura, and Chihiro Shimizu

Review of Income and Wealth 70 ( 4 ) 1142 - 1189 2024.01

Research paper (scientific journal), Joint Work, Accepted, ISSN 00346586

The current System of National Accounts (SNA) Gross Domestic Product (GDP) concept does not measure the income generated by the production sector since it includes depreciation and excludes capital gains and losses on assets used in the production sector. The paper suggests an accounting framework that measures the income generated by the production sector of an economy and implements this measure using the Augmented Productivity Database (APDB) developed by Asian Productivity Organization and Keio University for China over the years 1970–2020. Real gross and real net income generated by the Chinese production sector are decomposed into explanatory factors including TFP growth using the framework suggested by Jorgenson and Diewert and Morrison. TFP growth is further decomposed into technical progress and inefficiency components using the nonparametric approach developed by Diewert and Fox. The APDB has estimates for the price and quantity of agricultural, industrial, commercial, and residential land used in China. The paper argues that changes in land use should be treated in the same manner as inventory change and added to the alternative output measures. It turns out that Jorgensonian user costs for land are frequently negative. The problems associated with negative user costs are discussed in the paper.

Access to Document (DOI)

"A High-pressure Economy with a Sustainably Weak Yen is Desirable for the Japanese Economy" (in Japanese)

Koji Nomura and Koichi Hamada

Y. Harada and Y. Iida (eds.) What is High Pressure Economy (Kinzai) 43 - 65 2023.11

Part of collection (book), Joint Work, Lead author, Corresponding author

本稿は、戦後日本の経済成長の経験を振り返りながら、1980年後半以降の為替レートが多くの年で「過度の円高」であり、そして過度の円高が導く国内経済におけるコスト削減がどのように実現されたのかを解明する。見いだされることは、1980年代半ばまで「高圧経済」によって運営されていた日本経済が「低圧経済」へと移行してしまったことであり、それによる賃金抑制と生産性停滞こそが長期にわたり日本経済を苦しめてきたデフレ圧力の源泉となってきた。日本経済の復活に向け、高圧経済の実現への転換をいかにすべきかを論じる。

"The Growing Impact of ICT Productivity via the Cost of Capital: Evidence from the U.S. and Japan"

Mun S. Ho, Koji Nomura, and Jon D. Samuels

Telecommunications Policy (Elsevier) 47 ( 9 ) 2023.10

Research paper (scientific journal), Joint Work, Accepted, ISSN 03085961

We identify and measure two impacts of industry-level total factor productivity (TFP) growth on aggregate price change in the U.S. and Japan. The first is a standard effect from the definition of aggregate GDP. TFP change lowers aggregate prices ceteris paribus. The second is that a change in TFP in the production of investment goods lowers the cost of capital via lower investment prices. We call this the cost-of-capital effect and formulate an expanded growth accounting framework to capture both effects. We apply it to a harmonized dataset for the two countries and find that the standard effect has fallen since the peak around 2000 due to lower TFP growth and a diminished share of GDP. However, the cost-of-capital effect has risen in importance and offsets part of this decline in the standard effect.

Access to Document (DOI)

　 Previous page - Next page 　