Analysis of the Income Distribution Structure in Iran's Development Plans

Document Type : Research Paper

Authors

1 Department of Economics, Shiraz University, Shiraz, Iran.

2 Department of Physics, California Polytechnic State University, San Luis Obispo, CA 93407, USA. Department of Physics, Shiraz University, Shiraz, Iran.

Abstract

This study analyzes income distribution in Iran across six national development plans (1989–2022), focusing not only on inequality measures—such as the q_5/q_1 1 ratio, Palma ratio, Hoover index, and Lorenz curves—but also on the underlying structure of income inequality. A key contribution of this research is the combined assessment of both the level and the structure of inequality over time. Logarithmic differentiation is applied to determine whether changes stem from the top or bottom of the income distribution. Additionally, inspired by Sitthiyot and Holasut (2020), a composite index is developed by combining the Gini coefficient with decile-based ratios, allowing for structural differentiation even when Gini values are constant. The findings indicate that despite some fluctuations in standard indices, the overall structure of income distribution remained largely stable. Modest improvements occurred during the Third and Sixth Development Plans, while the First, Second, and Fifth Plans showed little to no progress. Over the study period, the Gini coefficient declined by 8.5%, the Hoover index by 9.8%, the Palma ratio by 18.2%, and the q_5/q_1 ratio by 20.7%. These results suggest limited structural change and highlight the need for more targeted and effective redistributive policies—especially under macroeconomic pressures such as inflation and external shocks.

Keywords

Main Subjects

Article Title [Persian]

تحلیل ساختار توزیع درآمد در برنامه های توسعه ایران

Authors [Persian]

  • مریم نوح پیشه 1
  • علی حسین صمدی 1
  • افشین منتخب 2
1 بخش اقتصاد، دانشگاه شیراز، شیراز، ایران.
2 بخش فیزیک، دانشگاه شیراز، شیراز ، ایران. گروه فیزیک، دانشگاه پلی‌تکنیک ایالتی کالیفرنیا، سن لوئیس اوبیسپو، کالیفرنیا ، ایالات متحده آمریکا.
Abstract [Persian]

هدف اصلی این مطالعه تجزیه و تحلیل ساختار توزیع درآمد در ایران در طول شش برنامه توسعه اقتصادی و اجتماعی و فرهنگی (۱۹۸۹-۲۰۲۲) است. در این مطالعه نه تنها بر معیارهای نابرابری مانند نسبت q5/q1، نسبت پالما، شاخص هوور و منحنی‌های لورنز بلکه بر ساختار نابرابری توزیع درآمد تمرکز شده است. یکی از دستاوردهای کلیدی این مقاله، ارزیابی ترکیبی سطح و ساختار نابرابری در طول زمان است. از تفاوت لگاریتمی برای تعیین اینکه آیا تغییرات از بالا یا پایین توزیع درآمد ناشی می‌شوند، استفاده شده است. علاوه بر این، با الهام از سیتیوت و هولاسوت (۲۰۲۰)، از یک شاخص ترکیبی (با ترکیب ضریب جینی با نسبت‌های مبتنی بر دهک ها) استفاده شده است تا امکان تشخیص تغییرات در ساختار توزیع درآمد- حتی زمانی که مقادیر جینی ثابت هستند، فراهم شود.  یافته‌ها نشان می‌دهد که علیرغم برخی نوسانات در شاخص‌های استاندارد، ساختار کلی توزیع درآمد تا حد زیادی پایدار مانده است. پیشرفت‌های اندکی در طول برنامه‌های توسعه سوم و ششم رخ داده است، در حالی که برنامه‌های اول، دوم و پنجم پیشرفت کمی داشته‌اند یا هیچ پیشرفتی نداشته‌اند. در طول دوره مطالعه، ضریب جینی ۸.۵ درصد، شاخص هوور ۹.۸ درصد، نسبت پالما ۱۸.۲ درصد و نسبت سه ماهه پنجم به سه ماهه اول ۲۰.۷ درصد کاهش یافته است. این نتایج نشان‌دهنده تغییر ساختاری محدود است و نیاز به سیاست‌های توزیع مجدد هدفمندتر و مؤثرتر  به‌ویژه تحت فشارهای اقتصاد کلان مانند تورم و تحریم‌های اقتصادی را برجسته می‌کند.

Keywords [Persian]

  • ساختار توزیع درآمد
  • نابرابری
  • ضریب جینی
  • شاخص مرکب
  • ایران

References

Abunoori, I., & Irji, F. R. (2004). Statistical comparison of income distribution in Khorasan province with the whole country (1350-1380). Quarterly Journal of Research in Economics and Planning, 9(1), 59-82.
Arabmazar, A., & Nourmohammadi, K. (2016). Critical analysis of the economic goals of Iran's development plans (before and after the Islamic Revolution). Social Studies and Research in Iran, 5(1), 19-42.
Arsalan-Bad, M. R. (2004). Changes in income distribution in rural and urban areas of Iran. Agricultural Economics and Development, 45, 123–140.
Atkinson, A. B. (1970). On the measurement of inequality. Journal of Economic Theory, 2(3), 244-263.
Atkinson, A. B. (2016). Inequality: What can be done. Practice, 40(2), 289-292.
Bonferroni, C. (1930). Elmenti di statistica generale [elements of general statistics]. Firenze: Libreria Seber.
Bruni, L., & Montesano, A. (2024). Vilfredo Pareto 1923–2023: A Special issue. International Review of Economics, 1-4.
Dara, J., & Alai, J. (2023). The Consequences of distributive and redistributive policies of the Islamic Republic of Iran based on the Almond-Powell and Robert Merton models. Strategic Policy Studies, 12(47), 39-72.
Ghasemi Dehaghi, M., Karami Moghari, Z., & Ilami, Z. (2023). The Impact of economic and political factors on income inequality in the first (1989-1993) and second (1994-1998) development plans. Economic Research and Policies, 31(106), 287-312.
Hasell, J. (2023). Measuring inequality: What is the Gini coefficient? Our World in Data. https://ourworldindata.org/gini-coefficient
Jenkins, S. (2017). The measurement of income inequality." In Osberg, L. (Editor), Economic inequality and poverty: International Perspectives, pp. 3-38. Routledge.
Karimi, M. Sh., & Durbash, M. (2018). Examining the impact of direct and indirect taxes on income distribution using the generalized method of moments. Iranian Economic and Social Research Journal, 12(4), 45-72.
Kazemi, M., & Zamanian, G. (2005). An analysis of income distribution in urban areas of Sistan and Baluchestan province. Geography and Development, 3(5), 141–160.
Loravand, H., & Lali, M. R. (2023). Investigating the income distribution status of Isfahan province using a parametric approach: 1391-1400. Research in Planning and Development, 4(3), 151-173.
Lorenz, M. O. (1905). Methods of measuring the concentration of wealth. Publications of the American statistical association, 9(70), 209-219.
Milani, A., Mohammadi, M., & Sidi, K. (2017). Progressive income tax structure and its impact on income inequality across the provinces of Iran. Economic Research Journal, 17(66), 1-22.
Milanovic, B. (2016). Global inequality: A New approach for the age of globalization. Harvard University Press.
Mossalanejad, A., & Mohammadzadeh, A. (2016). The Third development plan (2000-2004): Context, goals, successes, and failures. Strategy Journal, 25(79), 157-176.
Nezhadabdollah, M., Mohtashami Barzadran, G., & Yaghoubi Ol Rayabi, M. (2013). Income distribution indices in Iran. Economic Journal, 22(9), 49-64.
Palma, J. G. (2011). Homogeneous middles vs. heterogeneous tails, and the end of the ‘inverted‐U’: It's all about the share of the rich. development and Change, 42(1), 87-153.
Parvin, S., Bagheri Parmohr, S., & Pagardalishahi, F. (2019). The Impact of population aging on income distribution inequality in Iran. Population Studies, 5(1, Serial No. 9), 103-125.
Pavlov, O. I., & Pavlova, O. Y. (2021). Income inequality measures and the middle class. In SHS Web of Conferences (Vol. 114, p. 01019). EDP Sciences.
Rahnavard Ahan, F. (2022). General policies of development plans: A case study of Iran. Process of Management and Development, 35(3[121]), 3–55.
Ravallion, M. (2014). Income inequality in the developing world. Science, 344(6186), 851-855.
Rogerson, P. A. (2013). The Gini coefficient of inequality: A New interpretation. Letters in Spatial and Resource Sciences, 6(3), 109-120.
Shahbazi, Z., Habibpour, K., & Azkia, M. (2023). Analysis of Iran's social security system in post-revolution development plans. Welfare and Social Development Planning, 14(54), 105-146.
Sheikhi-Tash, M. N., Dehghani, A., & Sheikhi-Tash, M. (2008). Examining the trend of income distribution in Iran’s development and construction plans (1348-1383). Nameh Mofid, 14(66), 149–168.
Sitthiyot, T., & Holasut, K. (2020). A Simple method for measuring inequality. Palgrave Communications, 6(1), 1-9.
Wolfson, M. C. (1994). When inequalities diverge. The American Economic Review, 84(2), 353-358.
Yarahmadi, H., Taherinia, M., Givaki, E., & Talebnia, G. (2022). A Model for reducing the gap between self-reported taxable income and assessed taxable income. Journal of Accounting and Auditing Management, 11(44), 411-430.
Yashariel, S., & Habibian Naghibi, M. (2016). The Effect of targeted subsidy reforms on poverty and income distribution in Iran: A general equilibrium modeling of labor supply. Economic Modeling Research, 23(7), 159-196.
Zahedi Mazandarani, M. J., & Navaei, M. (2013). The conceptual system of justice and the feasibility of a justice theory for Iran's conditions. Conference on Conceptual and Theoretical Explorations of Iranian Society.
Zahedi, M. J., & Navaei Lavasani, M. (2016). Evaluation of the development plans of the Islamic Republic of Iran from the perspective of the representation and application of welfare and social justice theories (with emphasis on the fifth development plan). Social Studies and Research in Iran, 5(1), 43-78.

Files

History

  • Receive Date: 24 April 2025
  • Revise Date: 16 August 2025
  • Accept Date: 16 August 2025

Share

How to cite

Statistics