Economics Research

Analysis of the Asymmetric Effect of Oil Rent on Income Inequality in Iran: Focusing on the Role of the Underground Economy

Shahryar Zaroki; Ahmadreza Ahmadi

Volume 24, Issue 92 , April 2024, Pages 5-45

https://doi.org/10.22054/joer.2025.81163.1230

Abstract

Crude oil and the rents derived from it can present both advantages and disadvantages for oil-rich countries. Numerous studies have examined the impact of oil rents on various variables such as economic growth, inflation, and financial development. Among these, the potential role of oil rents in ... Read More Crude oil and the rents derived from it can present both advantages and disadvantages for oil-rich countries. Numerous studies have examined the impact of oil rents on various variables such as economic growth, inflation, and financial development. Among these, the potential role of oil rents in income inequality, particularly in light of the underground economy, appears to have been overlooked in previous domestic studies. To address this gap, the present research first calculates the relative size of the underground economy using a MIMIC method, revealing an average of 16.8% in Iran’s economy. Subsequently, employing a nonlinear autoregressive distributed lag (NARDL) approach, the study investigates and tests the effect of oil rents on income inequality while considering the underground economy over the period from 1978 to 2022. The long-run results indicate that positive shocks in oil rents are associated with a desirable (negative) effect on income inequality, while negative shocks lead to an undesirable (positive) effect. Furthermore, the underground economy acts as a double-edged sword; that is to say, an increase in the relative size of the underground economy has the potential to turn the favorable (negative) impact of positive oil rent shocks on income inequality into an unfavorable one, and conversely, it can transform the unfavorable (positive) impact of negative oil rent shocks on income inequality into a favorable one. Additionally, real GDP per capita exhibits an inverse U-shaped relationship with income inequality, while unemployment positively influences income inequality. Introduction A country’s progress toward social justice can be quantitatively assessed through indicators such as income distribution, poverty, and welfare. In recent years, rising concerns over income inequality have expanded the discourse on how natural resource rents—particularly oil revenues—shape economic growth and development. While resource abundance is often perceived as a blessing, its effects on economic development have been uneven and, at times, contradictory. Since the 1973 oil shock, Iran’s economic performance has been closely tied to its natural resource wealth. Moreover, a historical review of oil price trends reveals significant volatility, making it an unreliable source for financing national expenditures. According to theoretical foundations, natural resource rents should enhance the economic and social welfare of local communities. Ross (2007) notes that surprisingly little information exists about the relationship between natural resources and income inequality. However, it appears that resource-rich countries are, on average, neither more nor less unequal. Countries with abundant natural resources are often considered fortunate because these resources are valuable capital that can be transformed into essential infrastructure, fostering economic development and progress. Among natural resources, mineral resources—particularly hydrocarbons such as oil and gas—hold exceptional importance. The underground economy further complicates this relationship. As a parallel economic sector often linked to oil dependence, it diverts financial flows from formal oversight, undermining equitable wealth distribution. This not only deepens inequality but also erodes institutional quality and discourages human capital investment. In effect, overreliance on oil rents traps economies in cycles of distorted specialization and sluggish growth, perpetuating disparities. Despite these dynamics, few studies have examined the asymmetric effects of oil rents on income inequality or the mediating role of the underground economy—a critical gap this study addresses. Focusing on Iran (1978–2022), we investigate two central questions: First, does oil rent have an asymmetric effect on income inequality? Second, does the size of the underground economy influence how oil rent affects income inequality, and if so, how? Methods and Material First, the relative size of the underground economy is calculated using the MIMIC method. The structural equation model illustrates the relationship between the unobservable latent variable and observed indicators and causes. This model is widely used in various social sciences and economics. The MIMIC model consists of two main components: a structural equation and a measurement equation. As mentioned in the introduction, the primary objective of this study is to analyze and examine the asymmetric effect of oil rents on income inequality, with a focus on the role of the relative size of the underground economy in Iran. Therefore, the research model is designed to investigate and explain how increases and decreases in oil rents impact income inequality, emphasizing the relative size of the underground economy. To elaborate further, the reason for employing an asymmetric model lies in the limitations of symmetric or linear models, where the absolute magnitude of the independent variable's effect during an upward trend is assumed to be identical to its effect during a downward trend. In other words, in a symmetric estimation of oil rents impact on income inequality, it is conventionally interpreted that if an increase in oil rents leads to a rise (or fall) in income inequality by units, then simultaneously, a decrease in oil rents would result in a reduction (or increase) in income inequality by units. However, what occurs in reality may differ, as the effect of increasing oil rents on income inequality might not be identical to that of decreasing oil rents. In other words, in Iran’s economy, it is expected that income inequality will respond differently to increases in oil rents compared to decreases. Considering the explanations provided, as well as the potential delay in the impact of explanatory variables on income inequality and the influence of other variables affecting income inequality, a nonlinear autoregressive distributed lag (NARDL) approach is utilized. The asymmetric model specification is based on the study by Shin et al. (2014), which addresses the asymmetry in the coefficient of an influencing factor on the dependent variable under conditions of boom and recession. Drawing insights from the work of Pesaran et al. (2001), they define a model referred to as the nonlinear autoregressive distributed lag (NARDL) model. Results and Discussion The findings of the study, based on the estimation of the research model in the long run, indicate that: Firstly, positive shocks (increases) in oil rent have a favorable (negative) effect, while negative shocks (decreases) in oil rent have an unfavorable (positive) effect on income inequality. The difference in the magnitude of the impacts of positive and negative shocks highlights the asymmetric effect of oil rent on income inequality. Secondly, the favorable impact of increases in oil rent on income inequality diminishes as the size of the underground economy grows. Thirdly, the unfavorable impact of decreases in oil rent also weakens when the size of the underground economy increases. In a general summary and more detailed explanation, it can be stated that the underground economy acts as a double-edged sword in the relationship between oil rent and income inequality. Specifically, an increase in the size of the underground economy from 12.43% during increases in oil rent and 14.93% during decreases in oil rent makes the favorable (negative) impact of positive shocks in oil rent on income inequality unfavorable and turns the unfavorable (positive) impact of negative shocks in oil rent on income inequality into a favorable one. The inverse relationship between increases in oil rent and income inequality in Iran can be explained through channels such as increased government consumption expenditures, transfer payments and subsidies to lower-income deciles, and improved human development for the poor via government social spending. Furthermore, the results from the research model indicate that when disregarding the size of the underground economy, the favorable impact of increases in oil rent is less significant than the unfavorable impact of decreases in oil rent on income inequality, which confirms the presence of asymmetry in effects. Other findings show that real GDP per capita has an inverted U-shaped effect on income inequality, while unemployment has a positive effect on it. Conclusion Given the findings of this study, it must be acknowledged that oil rents are an unreliable resource. Therefore, adopting policies to reduce the country’s budgetary dependence on rents derived from natural resources, including oil, is essential. Additionally, it should be emphasized that to maximize the favorable impact of oil rents on income inequality during positive shocks, policymakers must account for the relative size of the underground economy and implement measures to reduce its scale (e.g., streamlining government regulations and bureaucratic hurdles for formal business entry, reducing trade restrictions, fostering formal-sector employment through prudent management of oil revenues, etc.). Furthermore, since the adverse effect of oil rent declines—which lies beyond the managerial capacity of oil-producing countries (assuming the underground economy’s size is disregarded)—exceeds the favorable effect of oil rent increases, establishing a foreign exchange reserve or national development fund is imperative.

The Effects of Human Resource Productivity on Economic Growth - An Intergenerational Approach

Esfandiar Jahangard; Mohammad Ghasemi Sheshdeh; Teymour Mohammadi; Farbod Jozani Kohan

Volume 24, Issue 92 , April 2024, Pages 46-98

https://doi.org/10.22054/joer.2025.81491.1234

Abstract

This study uses a three-period overlapping generations (OLG) model to investigate human capital productivity's impact on Iran's economic growth. The central question addresses how intergenerational transfers influence the productivity of human resources and, consequently, overall economic growth. ... Read More This study uses a three-period overlapping generations (OLG) model to investigate human capital productivity's impact on Iran's economic growth. The central question addresses how intergenerational transfers influence the productivity of human resources and, consequently, overall economic growth. Employing an analytical-quantitative approach, the study uses seasonal data from 1991 to 2021. The model is estimated within a Dynamic Stochastic General Equilibrium (DSGE) framework. By integrating data from national accounts and household budgets, the study derives productivity levels of human resources across generations. The findings reveal that intra-family transfers related to consumption, education, and healthcare significantly enhance productivity. Moreover, the age group 25 to 64 years shows the strongest impact on economic growth, which is consistent with the life-cycle hypothesis as formulated by Ando and Modigliani, as well as the theoretical perspective provided by the National Transfer Accounts (NTA) framework. Introduction The relationship between demographic dynamics and macroeconomic outcomes has become an increasingly important topic in economic research. Among the various mechanisms connecting these domains, the role of intergenerational transfers in shaping human capital productivity is especially significant. This study focuses on the Iranian context, where a shift in population structure, along with institutional and fiscal challenges, has made the efficient use of human capital a key policy priority. The central aim of this research is to assess intergenerational productivity through the lens of the National Transfer Accounts (NTA) framework. This approach allows for the quantification of how resources are allocated across age groups, highlighting differences in consumption, education, and healthcare. By identifying the age-specific patterns of resource use and output contribution, the study seeks to provide an empirical basis for measuring productivity across generations. Furthermore, to understand how productivity responds to macroeconomic fluctuations, the study incorporates a Dynamic Stochastic General Equilibrium (DSGE) model tailored to Iran’s economy. The model integrates shocks in key areas such as household consumption, educational investment, and health expenditures, and tracks their effects across different generational cohorts. Through this dual-layered approach—linking micro-level intergenerational data with macro-level modeling—the research aims to answer a critical question: Which generation is most responsive to shocks in ways that affect human capital productivity? Ultimately, the study provides not only a diagnostic tool for evaluating demographic-economic interactions but also a foundation for designing more targeted and effective policy interventions that consider the dynamic interplay between age structure, resource allocation, and economic growth. Methods and Material This study employs a hybrid modeling framework that combines National Transfer Accounts (NTA), the Overlapping Generations (OLG) model, and a Dynamic Stochastic General Equilibrium (DSGE) structure to assess the intergenerational dynamics of human capital productivity in Iran. The research integrates demographic structure with macroeconomic modeling to trace the effects of economic shocks on various age cohorts in terms of their productivity levels. The OLG model used in this study features a three-period structure consisting of youth (15–24 years), working-age adults (25–64 years), and the elderly (65 years and older). This categorization aligns with the age classification defined in the NTA framework. Each cohort is subdivided by skill level, which determines their human capital endowments. Individuals enter the model at the age of 15 and progress through the stages of life, contributing to or benefiting from the economy through consumption, education, healthcare, and labor productivity. To operationalize the model, we derive age-specific indicators for consumption, education, and health expenditures from household budget survey data. These micro-level estimates are then scaled using aggregate national account data to compute public and private intergenerational transfers. For example, to determine the public health transfer received by each age group, the proportional share of health-related household spending is multiplied by total government health expenditure. A similar technique is used to calculate age-disaggregated values for other transfer categories such as education and consumption. The DSGE model is calibrated using quarterly macroeconomic data from 1991 to 2021. This framework enables us to incorporate random shocks to productivity, consumption, and fiscal policy, allowing for an analysis of the short- and long-term effects of these disturbances across different generations. The model builds upon the microfoundations of rational expectations and utility maximization, and follows the tradition established by Kydland and Prescott (1982), Clarida et al. (2002), and Smets and Wouters (2003). Technological shocks are modeled as a primary source of uncertainty, in line with the Real Business Cycle (RBC) literature. Despite some limitations—such as the complexity of infinite-horizon modeling and the challenge of solving nonlinear systems—DSGE models remain the gold standard for macroeconomic policy simulation. This study utilizes a finite-horizon version of the model to capture the productivity responses of distinct age cohorts to economic shocks. By integrating NTA data into a DSGE structure, the research bridges microeconomic resource allocation with macroeconomic performance. It further distinguishes itself by evaluating how generational productivity changes in response to policy-driven and exogenous shocks, providing a novel analytical tool for demographic-economic research. Results and Discussion Although the calibration techniques of microeconomic and macroeconomic models slightly differ, the general approach in economic literature includes four key steps: selecting the model, defining the calibration objective, specifying the functional form, and adopting parameters estimated by other researchers or through original estimation. Table 2 presents the calibrated parameters and their estimation methods. One of the crucial outputs of the Dynare software is the Markov Chain Monte Carlo (MCMC) diagnostic test, which confirms that there is no issue with the model’s parameter estimations and that the estimates are reliable. Dynare performs several Metropolis-Hastings simulations, starting each time from a different initial point. If the chains behave similarly and converge toward one another, the results are considered trustworthy. Dynare provides three diagnostic indices—Interval, m2, and m3—which represent the 80% confidence interval, variance, and third moment of the parameters, respectively. These are visualized in multivariate diagnostic plots, illustrating the eigenvalue-based diagnostics of the variance-covariance matrix for each parameter. These charts provide evidence of convergence and stability across all parameter moments. The x-axis in each chart shows the number of Metropolis-Hastings iterations, and the y-axis indicates the parameter moments. A lack of similarity across plots suggests incorrect priors and may warrant re-estimation or more iterations. As shown in Figure 8, the curves converge toward each other, indicating a good model fit. Table 1. Calibrated Parameters Parameter Name Symbol Prior Distribution Posterior Distribution Distribution Type Time Preference Rate γ 0.968 0.967 Gamma Labor Force Growth Rate β 0.035 0.04 Beta Social Security Tax Rate γ 0.32 0.35 Gamma Intertemporal Substitution Elasticity γ 0.92 0.95 Gamma Intra-period Substitution Elasticity γ 0.79 0.81 Gamma Leisure Preference Rate (Age 1–30) γ 0.29 0.31 Gamma Leisure Preference Rate (Age 31–55) γ 1 1 Gamma Productivity Growth Rate β 0.015 0.02 Beta Capital Share in Production γ 0.53 0.61 Gamma Private Household Consumption Transfer Rate β 0.34 0.32 Beta Private Household Health Transfer Rate γ 0.18 0.19 Gamma Private Household Education Transfer Rate β 0.24 0.23 Beta Public Consumption Transfer Rate γ 0.29 0.28 Gamma Public Health Transfer Rate γ 0.37 0.38 Gamma Public Education Transfer Rate γ 0.44 0.39 Gamma Source: Research Study The dynamic behavior of economic growth variables in response to various shocks was examined using impulse response functions. Table 3 summarizes how different generational cohorts respond to intergenerational transfers in key domains—household consumption, education, and healthcare, as well as public transfers. Overall, results indicate that household-based transfers are more effective and positively correlated with productivity and economic growth compared to public sector transfers. Households seem to allocate resources intergenerationally in a more optimal way, particularly in the domains of health and consumption. Conversely, public sector allocations often fail to produce the same economic impact, possibly due to inefficiencies in governance, planning limitations, and resource misallocation. Table 2. Production Response to Various Intergenerational Transfer Shocks Shock Type Age 0–24 Age 25–64 Age 65+ All Age Groups Household Consumption Transfer Positive impact throughout Positive impact throughout Negative impact throughout Positive impact throughout Household Health Transfer Initially negative, then positive Positive throughout Positive throughout Positive throughout Household Education Transfer Negative throughout Positive throughout Negative throughout Positive throughout Public Consumption Transfer Negative throughout Positive throughout Positive throughout Positive throughout Public Health Transfer Initially negative, then positive Initially negative, then positive Negative throughout Positive throughout Public Education Transfer Negative throughout Initially negative, then positive Negative throughout Positive throughout The findings suggest that households tend to allocate intergenerational resources more efficiently, leading to higher productivity across most generations. The public sector, in contrast, appears less effective in aligning transfers with economic growth objectives. These discrepancies may be attributed to governance inefficiencies, widespread corruption, and the lack of long-term strategic planning. Conclusion National Transfer Accounts (NTA) reflect the quantity and structure of economic flows across age groups and generations. These intergenerational flows are crucial as they embody a fundamental feature present in all societies. The findings of this study highlight that household-based transfers—particularly in consumption, education, and healthcare—are more effective than government-based transfers in enhancing human capital productivity across generations, thereby fostering economic growth. The results reveal that the age group of 25 to 64 years contributes most significantly to economic growth, consistent with the life-cycle theory as proposed by Ando and Modigliani and further supported by the intergenerational perspective of the NTA framework. Based on the empirical findings, the following policy recommendations are proposed: Enhancing Public Transfer Efficiency:Given that public transfers in consumption, education, and healthcare are generally less efficient—especially outside the 25–64 age range—it is recommended that the government allocate resources more effectively in accordance with the productivity levels of different generations. Such alignment could enhance the efficiency of public spending and improve intergenerational productivity outcomes. Facilitating Private Transfers:Since intergenerational transfers have a positive impact on labor productivity, and household-level transfers outperform public transfers in terms of effectiveness, it is recommended that the government minimize disruptions in private transfers by mechanizing and streamlining the transfer processes between households. Extending the Demographic Dividen: Considering the relatively limited contribution of the retired population to economic growth and their impact on both the first and second demographic dividends, policies should be designed to delay the depletion of these dividends. Potential strategies include promoting financial literacy in retirement, extending work life in low-intensity occupations, increasing human capital among the elderly, leveraging gender dividends by expanding female labor force participation, and improving consumption and healthcare patterns among retirees. Additionally, long-term strategic foresight in retirement policy is essential. Harnessing Youth Potential:On one hand, the young, educated population represents a latent advantage for growth and development; on the other hand, labor market limitations hinder their absorption, leading to rising unemployment and reduced youth productivity. Emphasis should be placed on fostering entrepreneurship among youth through legal, educational, and financial support. Encouraging youth-driven innovation, human resource planning, and investment in digital economic sectors—where younger generations demonstrate high adaptability—can help address this challenge. Aligning with Macro-Level Population Policies:At the macro policy level, these recommendations align with several of the Supreme Leader’s population policy guidelines, especially clauses 6, 8, and 10, which emphasize the importance of leveraging both demographic dividends. These include increasing life expectancy, promoting health and nutrition, empowering the working-age population through vocational and entrepreneurial training, and supporting rural and border populations through investment and job creation. Additionally, prioritizing knowledge-based economic development—consistent with successful global experiences—can enable Iran to fully capitalize on its second demographic dividend for achieving sustainable economic growth. Acknowledgments The authors of this article sincerely express their gratitude to the editorial board and the esteemed members of the journal’s editorial team. Their support, attention to detail, and constructive guidance throughout the review and publication process have played a significant role in enhancing the scientific and editorial quality of this work. Undoubtedly, the valuable efforts of this dedicated team in advancing the journal’s academic mission and supporting researchers are worthy of appreciation and recognition.

An Investigation on the Effect of Tax Avoidance on the Transparency of Financial Reporting Firms Listed in Tehran Stock Exchange

Volume 14, Issue 52 , April 2014, , Pages 85-69

Abstract

Abstract In this paper, the impact of tax avoidance on the transparency of financial reporting of firms listed in Tehran Stock Exchange is investigated. The indexes that are used to measure tax avoidance and financial reporting transparency are respectively effective tax rate and accruals quality. The ... Read More

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Volume 2, Issue 7 , January 2003, , Pages 165-199

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Volume 5, Issue 18 , October 2005, , Pages 13-47

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The concept and measurement of economic Resilience

Volume 15, Issue 59 , January 2016, , Pages 161-187

Abstract

In this paper, resilience of an economic system is measured by an overall index, based on the Borman et al. index, for the period of 1996-2013. The results are then compared with Briguglio index. To measure the final index, the first step is to make variables have a similar direction. The second step ... Read More

Ranking Branches of the Banks in Iran

Volume 7, Issue 26 , October 2007, , Pages 305-348

Abstract

Commercial banks basically offer their services in three fields: resource mobilization, financial resources allocation and their banking services. These services are offered by their branches all over the country. These branches are essential into different grades: Independent, Grades 1, 2, 3, 4, and ... Read More

Examining the role of household financial status in electricity consumption behavior with using a survey

maryam keyghobadi; elaheh sadat akbarnia; hamidreza pirmorad; asharaf-sadat pasandideh

Articles in Press, Accepted Manuscript, Available Online from 22 January 2025

https://doi.org/10.22054/joer.2025.78344.1202

Abstract

Household electricity consumption is one of the most important and challenging consumption sectors that has caused imbalance energy consumption in the country. The purpose of this research is to understand the consumption behavior of citizens in order to improve behavioral policy. In this regard, the ... Read More

Time-Varying Volatility Spillovers between Exchange Rate and Tehran Stock Exchange; New Evidences of Covid-19 Pandemic

Reza Taleblou; Parisa Mohajeri; Maedeh Samadi

Articles in Press, Accepted Manuscript, Available Online from 11 February 2025

https://doi.org/10.22054/joer.2025.78828.1209

Abstract

This study employs the Diebold-Yilmaz spillover index within the framework of a time-varying parameter vector autoregressive model (TVP-VAR) to analyze the dynamic connectedness between exchange rates and the Iranian stock market amidst the COVID-19 pandemic. Utilizing daily data spanning from October ... Read More

The Effects of Macro-fiscal Determinants on Fiscal Deficit in Iran

Samira Ejtehadi; Hashem Zare; mehrzad ebrahimi; Mohammad Ali Aboutorabi

Articles in Press, Accepted Manuscript, Available Online from 23 February 2025

https://doi.org/10.22054/joer.2025.83075.1240

Abstract

This paper aims to explain the real-fiscal linkages by identifying the macroeconomic determinants of the operational fiscal deficit in Iran from 1972 to 2020 using the Dynamic Ordinary Least Squares (DOLS) method. The findings indicate that economic growth, inflation, centralization, the size of the ... Read More

Efficiency Effect of Unification on Iranian Water Utilities

Mahdi TORKAMANI; Akbar Khodabakhshi

Articles in Press, Accepted Manuscript, Available Online from 23 February 2025

https://doi.org/10.22054/joer.2025.75973.1161

Abstract

Water utilities provide one of the most crucial services to boost health and welfare of communities. In Iran until 2019, the utilities in urban and rural areas were independent, and in each province there were an urban water utility and a rural water utility serving urban and rural areas respectively. ... Read More

Investigating the indicators of attracting foreign tourists to Iran using panel analysis and gravity model

Ali Asghar Heidari; Sobhan Pirahan siah; محمدعلی آغنده

Articles in Press, Accepted Manuscript, Available Online from 19 May 2025

https://doi.org/10.22054/joer.2025.83414.1244

Abstract

The rapid development of international tourism, today, is due to social, cultural, economic, political, and technological changes. It has shifted the tourism flow from developed countries to newly industrialized ones. International tourism demand is estimated by factors such as the number of incoming ... Read More

Environmental Consequences of Imposing Economic Sanctions in Iran: Applying Dynamic Computable General Equilibrium Model

behzad sadeghvand; Hassan Heidari; Mehdi Nejati

Articles in Press, Accepted Manuscript, Available Online from 19 May 2025

https://doi.org/10.22054/joer.2025.80917.1229

Abstract

Iran is simultaneously facing the issue of sanctions and their adverse effects on various economic sectors, as well as numerous environmental challenges. The main objective of this research is to examine the extent to which sanctions exacerbate environmental problems in Iran. For this purpose, the effects ... Read More

The Role of Individualistic Social Norms in the Level of Charitable Giving in Society: A Case Study of Iran

mostafa kazeminajafabadi; Ahmad Ali Rezai

Articles in Press, Accepted Manuscript, Available Online from 26 May 2025

https://doi.org/10.22054/joer.2025.84484.1256

Abstract

While individualism is often perceived as a negative factor that undermines social ethics and reduces participation in charitable activities, this study proposes the hypothesis that individualism—as a set of cultural values and norms that place the individual at the center of decision-making and ... Read More

Dynamic optimization of oil production and estimation of taxation effects on the income of the oil investor company

PARISA GHOLIPOUR FEIZI; GHODRATOLLAH EMAMVERDI; Marjan Damankeshideh; ALI ASGHAR ESMAILNIA KETABI

Articles in Press, Accepted Manuscript, Available Online from 01 June 2025

https://doi.org/10.22054/joer.2025.81073.1232

Abstract

Since the income tax of a production company may reduce its profit and optimal production, this study investigates the effects of such taxes on the discounted profit, optimal production rate, and finally, the changes in the optimal path of oil production of the company to generalize the mentioned subject ... Read More

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