فصلنامه اقتصاد مقداری
سال هجدهم شماره 1 (پیاپی 68، بهار 1400)

Reducing inequality, adjusting incomes, and redistributing issues become the biggest goal of development economics and the most difficult task for policymakers when viewed in conjunction with economic growth. Because achieving high growth rates, in addition to its own difficulties, also raises the concern that providing accelerated growth may lead to disruptions in income distribution. Therefore, explaining the causal relationship between growth and income distribution and how to determine the relationship between these two variables and then applying optimal growth and distribution policies has particular importance.Numerous studies have been conducted in different societies in this field, which is mainly based on Kuznets (1955) hypothesis of "income growth and distribution". In his studies, Kuznets observed a parabolic relationship between per capita income and income inequality and explained this relationship as follows: In the stages of economic development, the lowest and highest values ​​of per capita income with low inequality and the mean values ​​of per capita income with degrees More of the corresponding inequality. Using statistics from the United Kingdom, Germany, and the United States, he empirically estimated the impact of economic growth on income distribution and observed that income distribution inequality increased during the first stages of economic growth, and then It balances and eventually declines during the final stages of economic growth. However, the results of empirical studies show that the Kuznets hypothesis has not always been confirmed and the relationship between economic growth and income inequality is not predictable, and depending on which country (or group of countries) this issue is examined, the relationship Positive, negative, meaningless or nonlinear will be obtained.For this reason, a new approach to the issue of economic growth and income inequality in macroeconomics has emerged among some economists, especially since the early 1990s. Attitudes that mainly believe that contrary to Kuznets, who considered only economic factors in explaining this relationship, the relationship between these two elements is endogenous and in addition to economic factors, is also a function of social and political factors as a result of developments. Politically and institutionally, societies are affected. Therefore, researchers are looking for variables that provide a more comprehensive understanding of patterns of growth and income inequality, and at the same time can achieve economic growth and income distribution at the same time. In this regard, the purpose of this article is to investigate the effect of democracy on the relationship between economic growth and income inequality in Iran. Theoretically, it is expected that the establishment of a democratic culture in society, in addition to providing suitable conditions for productive economic activities, will lead to reduce income inequalities and class conflict through the process of public participation and the expansion of justice for all. The side should be reduced in the shadow of democracy. But in fact there is no clear connection between this, and the effect of democracy on economic variables depends to a large extent on the actual distribution of power.Political elites can increase investment in real power (through control of local actors, mobilization of non-governmental military forces, political lobbies, and other means of controlling party rule) under certain circumstances that threaten the rule of law democracy. It is natural that in such an environment, democracy will have little effect on the redistribution of wealth and the reduction of inequality and economic growth. In addition, the democratic process may be limited by institutions such as the constitution, conservative political parties, judges, the real threat of a coup, and even widespread tax evasion, and as a result its economic effects diminished. So there is no exact relationship between democracy and the variables of growth and inequality, but this does not mean that basically any relationship is ruled out, but it is most likely due to the complex and different relationships between democracy and economic variables that pay attention requires more comments on this article.Theoretical explanation of the relationship between economic growth and income distribution can answer one of the fundamental questions of economic planners, especially in developing countries. Because these countries have always suffered from low levels of per capita income and wide income gaps. It can be said that eradicating poverty and reducing income inequality, when combined with economic growth and institutional and political reforms, becomes the biggest goal and the most difficult task of economic policy makers in developing countries.In the case of a country like Iran, of course, how the development process can be effective in the relationship between growth and income distribution. For this reason, in this article, the effect of democracy as a political variable on how this relationship is examined to clarify the effect of the expansion of democratic institutions on the problems of economic growth mismatch with income inequality at the same time and not by leaving one in favor of the other.

This research is causal and the data are extracted in the form of a library (general information and required data from the World Bank website, time series statistics published by the Statistics Center of Iran, the Central Bank and reports related to the policy project). The population studied in this research is Iran in 1971-2018.Due to the nature of the data, Autoregressive Distributed Lag (ARDL) method has been used to estimate the model. Excel, Microfit 4.1, Eviews9 software packages have been used for this purpose.The research is organized in such a way that after stating the introduction, the literature is briefly reviewed and the research model and variables are identified. Then, the model estimation and econometric tests necessary to check the accuracy and stability of the coefficients and results are performed, and at the end, we summarize the conclusions and present some suggestions.

According to the results of the research model (political economy of Kuznets curve), although Kuznets hypothesis (relationship u form of income inequality and economic growth) in Iran is not rejected, but considering the effect of the political institution of democracy has reduced the negative impact of growth on inequality Also, the inclusion of the variable of democracy in the model shows the opposite and significant effect of growth associated with democracy on income inequality, meaning that inequality is destructive and changes in the political regime (expansion of democracy) lead to redistribution. In fact, based on the theoretical foundations of this model, the Kuznets hypothesis is formed, but increasing inequality in society causes the masses of ordinary people who are dissatisfied with the current situation to form organizations and institutions for the realization of rights. Therefore, politicians who feel threatened have to put reform programs and redistribution policies on their agenda in order to avoid the risk of coup and revolution. As a result, it can be said that political reforms and democratic measures reduce inequality while increasing economic growth.

Based on the results of the estimation model:1- Kuznets hypothesis has been accepted with a high percentage of confidence in the research period. Economic growth has an increasing effect and squared Economic growth has a decreasing effect on income inequality and the intensity of these effects is greater in the long run. This confirms that tolerating a percentage of inequality in society to achieve a certain level of growth for economic development is inevitable, that with increasing the level of development, the effect of growth on inequality is reversed and the possibility of growth with proper income distribution Will be provided.2- Inflation has a direct and significant effect on income inequality, which means that increasing inflation widens the income gap of society. This result is consistent with the studies of Abu Nouri (2006) and Georgia (2008).3- The ratio of oil revenues to production has had a direct effect on income inequality. Thus, rising oil revenues have fueled severe inequalities. This result is consistent with the rentier government hypothesis in the Iranian economy that stakeholders are trying to gain as much share of oil rents as possible by influencing the budgeting and allocation process. Give. Therefore, it seems that increasing oil revenues by increasing access to foreign exchange resources and importing more consumer goods, provides the basis for unproductive activities and increasing income gaps.4- The inclusion of the Democracy Index in the model has reduced the negative effects of economic growth on inequality to an acceptable level (although the Kuznets hypothesis is still valid). Under democratic conditions, it is possible to achieve both components of economic growth and reduce inequality at the same time, but in the empirical analysis of these results, it is necessary to consider that the nature of the institution of democracy may prevent an immediate effect in this regard. The lower coefficient of this variable in the short run compared to the long run also confirms this.It should be noted that in order to ensure the accuracy of the results of econometric model estimates, tests of classical assumptions and to check the stability of the model, Cumulative Sum Of Recursive Residuals and Squares Of Recursive Residuals tests wereperformed for the specified model, the results of which indicate the establishment of Classic assumptions as well as model stability. Given the growing impact of growth on inequality in the early stages, it is likely that pursuing growth-oriented policies, regardless of their distributional consequences, will lead to a worsening of the income distribution situation in Iran. Therefore, in order to achieve both important development goals, namely economic growth and income distribution, it is necessary to consider growth strategies combined with redistributive policies.

Recent theories regarding economic growth show that research and development (R&D, hereafter) activities are of the most salient factors in the process of science production and play an important role in improving the productivity level of all production agents. That is why, developed countries pay special attention to such activities and allocate and invest high research budgets in these areas. However, due to low R&D budgets and limited capital resources for manufacturing enterprises in developing countries, these countries can benefit from the overflow of international R&D activities, hence improve the total productivity of their production agents. But the important issue is that, some internal and/or external factors, such as the absorption capacity of countries and/or the degree of their relative backwardness can affect the impact mechanism of the overflows with regard to productivity and cause some possible nonlinear effects. To investigate these possible nonlinear effects, more flexible methods are required to enable appropriate identification and investigation of the behavior of these factors in terms of the impact mechanism of international R&D spillovers.Accordingly, in the present study, the threshold effects of absorption capacity and relative backwardness on international R&D overflows in developing countries is investigated. The nonlinear panel smooth transition regression (PSTR) is used in order to investigate the subject matter of the current study within the time period of 1995-2015. For this purpose, the impact channel of international research and development overflows on the total efficiency of production factors was used; in two separate estimates, the effectiveness of the two variables of absorption capacity transfer and relative backwardness on the performance of international R&D overflows, and consequently the total productivity of the production factors were examined.

Given that in regression models based on panel data, heterogeneous temporal and cross-sectional effects in the data are determined by the fixed and random effects model, and in such models the elasticities (coefficients of variables) ) Between countries and over time, a linear equation cannot allow changes in the productivity of total factors of production to reflect all possible nonlinear effects relative to the R&D overflow. In this study, in order to investigate and test the relationship between variables, the panel model uses a gentle panel regression regression econometric technique. For this purpose, following the study of Gonzalez et al. (2005) and colitis and Harolin (2006), a two-diet PSTR model with a transfer function is first defined as follows:(1)    In relation (1), i = 1,…, N and t = 1,…, T, respectively, represent the sections and time dimensions of the panel data. The dependent variable indicates the productivity of all factors of production, and the independent variables, respectively, indicate the overflow of domestic R&D, human capital and the overflow of international R&D. The fixed effects of sections and sentences are model errors that are considered as follows. It also represents a continuous and finite transfer function between zero and one. According to the theoretical and experimental foundations in the field of study, in this study, the variables of absorption capacity and relative backwardness (degree of development) have been selected as the transfer variable.

According to the results and considering the threshold effects of absorption capacity and relative backwardness, the international R&D overflows impact factor on the total productivity of production factors increases. In other words, the results showed that, the variable of absorption capacity, which is equivalent to the average years of human resource training, has a positive and significant effect on the international R&D overflows impact with regard to the total efficiency of production factors in developing countries. That is, by increasing the threshold limit of absorption capacity, the effect of overflows on the productivity also increases. Therefore, developing countries need a certain amount of human resource training in order to enable them to benefit from the effects of the international overflow on total productivity of the production factors. Also, the relative backwardness index acts directly, and with an increase of technological gap in developing countries and moving away from the leading country (the United States is considered in the current study) the extent of the international overflows impact on the total productivity of production factors increases. But this increasing trend will exist to some extent of the backwardness. Of course, it is worth noting that, according to the results, this direct relationship is established up to a certain threshold level of the absorption capacity and relative backwardness in developing countries and in countries with very high absorption capacity or are greatly lagging behind. The linear regime determines the behavior of variables and as such, the influence coefficient of overflows on the total productivity of production factors in these countries is reported to be weaker. 

Therefore, in order to reap the benefits of R&D international overflows to improve their productivity, it is recommended that developing countries should identify their potentials in international trade and consider the areas of R&D overflows that benefit them most. In addition, by efficiently training and educating specialized human resources and strengthening the internal absorption capacity, these countries will be able to absorb and localize new technologies and provide the ground for absorbing as many overflows as possible. Also, by proper policy-making in the use of domestic resources, these countries can allocate appropriate budgets for domestic R&D activities and seriously monitor them by strengthening domestic production to varying degrees of development. Accordingly, they might become able to reduce their technological gap from leading countries so that they can make the most out of their international trade, and by attracting more foreign technologies, compete effectively in the global arena and benefit from overflows to improve their productivity.

Along with the competitive behavior of producers, consumers’ behavior significantly influences the market structure. The temporal resolution of recursively repetitive interactions between producer firms and consumers creates and shapes the structure of the market and defines the firms' market shares. In order to explore this issue, we require a comprehensive model considering the behaviors of both sides, such that the variation of the parameters of the model reflects the competitive policies of the producers and the diversity and differences among the spirits of the consumers. The proposed model of this paper is based on these viewpoints and, by variation of its parameters, the effects of consumers’ behavior and moods on producers’ market shares are simulated. The developed model includes two sub-models. The first is based on the theory of differential games to represent the competitive behaviors of producers. The second is agent-based which is developed through learning and choice pattern to illustrate the consumers’ behavior in an oligopoly market. In a numerical example of this model, producers apply their policies in 5 intervals such that between any two intervals of policy application, consumers buy and consume goods in 5 subintervals through which the consumers have the opportunity to learn and gain new experience. In this example, it is observed that the tendency of consumers towards new experiences, the degree of relative importance, that the consumer attaches to their high level of desires, the duration or opportunity of learning and gaining new experience and the delay in the policy implementation, all together, affect the market shares of producers. It is also shown that from perspective of this model, market shares do not change dramatically compared to their initial conditions in the case of belief-based learning; but, in the case of reinforcement learning, consumer behavior becomes more random. In case of belief-based learning, it is expected that as the number of consumers seeking new experience decreases, the market shares diverge. Similarly, increasing in the degree of optimization in the random selection law, in both belief-based and reinforcement learning cases, leads to the increasing of the divergence in market shares. Here, the number of sub-intervals indicates the required time for producers to implement their new market policies. As the number of sub-intervals increases or decreases, convergence of market shares increases, under both types of learning. Delays in the implementation of policies by a producer, in the case of belief-based learning will be in its favor; and, in the case of reinforcement learning such delay will be in adverse of that producer. The presented model of this paper can be used by firms to test their competitive policies, by looking at different scenarios related to environmental conditions and the behavior of consumers prior to deployment of those policies.

One of the factors affecting economic growth along with traditional factors of production such as labor force and capital  is structural changes in the economy. Structural change is a broad economic process that involves changes in the structure of production and employment within and across sectors of the economy. The emergence of new activities and sectors in the economy and the disappearance of old activities and sectors are also indicators of structural changes in the economy (Gabardo  et  al., 2017, p. 5). From the perspective of a well-structured economy the countries and regions that have a production structure commensurate with regional and national potentials can experience faster economic growth, and countries that depart from this well-structured position, will have a less economic growth (Eigner, 2001, p. 3). Therefore, investigating the effect of structural changes on macroeconomic variables and then identifying the factors influencing structural changes can provide a good basis for policymakers to remove the barriers of structural change and thereby achieve greater growth and development in the regions and also in the country. Economic growth and development in an area can be influenced both by specific characteristics within the region (direct and intra-regional effects) and by the characteristics of the surrounding area (spillovers and inter-regional effects) (Sharify and Hosseinzadeh, 2016, p. 2). Disregarding the interconnections and spillover effects between the variables can cause the model results to be biased. One of the models that is able to consider inter-regional correlations and consider the spillover and indirect effects of variables is the spatial econometric model.

The main purpose of this study is to investigate the direct and spillover effects of structural changes on economic growth in 28 provinces of Iran during 2004-2015 using spatial econometric model. An important feature of this study compared to previous studies in the field of structural change impact is the use of spatial econometric model to study the direct and spillover effects of this variable on economic growth in different provinces of the country. The production data of different economic sectors were used as the statistical bases for calculating the structural change and Gross domestic production index in 28 provinces of the country. Also, government expenditure and provincial  active population variables were used as control variables. Finally, the Spatial Durbin Model (SDM) and the Stata 14 software were used to estimate the model.

The results of the model estimation showed that structural  changes directly and indirectly had a significant and negative impact on the production of regions. This indicates that structural changes have not been consistent with the regional growth pattern. Also, government spending variables in the region and the active population of the region had a positive and significant direct effect on regional economic growth.

Based on the results of the research, it can be concluded that the economic structure in different provinces of the country should be changed in accordance with the regional advantages. Government spending should also increase in line with regional potential.

Poverty is a fundamental multidimensional phenomenon which has always been and is one of the most important detriments to societies and the root of the problems and hindrances of most parts of the world. Efforts to eliminate this social problem are one of the most prominent goals of economic growth and development; and despite economic growth in underdeveloped or developing countries, this problem persists. .Although growth in income, as one of the macroeconomic variables, has a significant effect on poverty and its reduction, but the existence of inequality and its effect on economic growth plays an important role in benefiting the poor from economic growth. In the process of economic growth, what reduces poverty is an increase in household income; thus, the distribution of income among households should be such that the poor also benefit from this growth. Therefore, economic growth is not sufficient to eliminate poverty on its own, and its effect on poverty is not the same at different times and places, and the manner in which the benefits of growth are distributed is significant as well. Inequality and poverty are two completely different concepts, but they are deeply related. Therefore, paying attention to economic growth and reducing inequality can have good results in reducing poverty. In recent decades, societies that have focused on both economic growth and reducing inequality have been much more successful in reducing poverty. In this regard, to understand the effects of economic growth on poverty, it is necessary to distinguish between the effects of economic growth on poverty and the effect of inequality on poverty. Then, the change in the poverty index is broken down into a change in average incomes and changes in income inequality to properly determine the contribution of income and inequality in poverty decrease.

in the present study, the effects of income and inequality and their resultant on reducing poverty in the provinces of Iran over a fourteen-year period, from 2004 to 2018, have been determined using the Sen Index, the Kakwani method, and various mathematical methods.

As confirmed by our study results, both income effects and inequality effects had performed in favor of the impoverished in the province of Yazd and led to poverty reduction, while in Kermanshah, Khorasan Razavi, Isfahan, and Zanjan the income effects and inequality effects have somewhat neutralized one another. In other words, even though the increase in the average income reduced poverty, the increased inequality led to increased poverty. On the other hand, the situation in the province of Alborz was considerably different. In this province, although decreasing the average income increased poverty, the improvement in income distribution not only eliminated the negative effects of the income share, but also reduced poverty. However, the income effects and inequality effects had moved in the same direction in Gilan, Khuzestan, Fars, Hamedan, Chaharmahal & Bakhtiari, Lorestan, Tehran, Qom, North Khorasan, and Sistan and Baluchestan, to increase poverty. Finally, in other provinces, the distribution of income has changed in a way that despite the increase in average incomes, poverty increased.

Therefore, as the research findings show, poverty has decreased in only a few provinces during the period under review. And the inequality effects and the income effects, or both, have led to increased poverty. Therefore, in order to reduce poverty, economic growth and reduce inequality must be given much attention.

In many cases, it is necessary to rank among the limited number of investment options in order to choose one. The ranking is based on the priorities and benefits of each one compared to the other, which is usually offered in terms of certain indices. Thus, the position of each investment option is determined in relation to the other options and the decision maker can make the right choice by assuring the superiority of each one over the other. On the other hand, investment funds can play a major role regarding public interest in the stock market and contribute to reducing inflation, increasing production and boosting the national economy by adopting appropriate policies. On this basis, besides considering the role of utility in decision-making, and investor’s risk-taking, the aim of this study is to use a hybrid model of clustering and utilities additives discriminates (UTADIS) methods to rank and form a portfolio of exchange traded funds.

This research is applied in terms of purpose and descriptive in terms of data collection method, and the analytical-mathematical method has been utilized in it. Regarding the field of research, it falls under operational and financial management. The data were analyzed and the variables were calculated using Excel. Based on the obtained information and using MATLAB, cluster analysis was done applying the k-means method. Finally, the calculation of the utilities additives discriminates (UTADIS) method was calculated using Excel and GAMS and the initial model was solved.

In this study, during a five-stage process, first the exchange traded investment funds were chosen for ranking as a case study, and from 32 Exchange Traded Funds (population), 26 Funds from Iran’s capital market were selected as samples from March 2013 to November 2018. In the second step, three benchmark groups consisting of performance evaluation general criteria (return, risk and portfolio beta), modern criteria (sharp, treynor, Jensen and M2 ratios), and postmodern criteria (omega, sortino, kappa and upside potential) of the portfolio theory used in earlier research were calculated for the sample funds and were clustered with the mentioned criteria using the K-means method. Afterwards, considering certain validation indexes, the ideal number of clusters was determined. The results of the clustering method were the input data of the UTADIS method and the funds were ranked. After solving the primal model, in order to improve the results, a post-optimality analysis was done, after which, the weight of the criteria and the utility of alternatives were determined. Then in order to validate the results, the classification results validity test and the classification error test were carried out. 

The results show that the hybrid method used was suitable and the return index with a weight of 0/153 had the biggest role and the Treynor ratio index with a weight of 0/039 had the smallest role in the Investment Portfolio. Also, with regard to the obtained results from the classification validity and testing the test sample, it was determined that the model was 100 percent accurate. Finally, three exchange traded funds of Arman Ati Kosar, Kian fund, tradable with a fixed income and Parand Paidar Sepehr, fell into the first cluster according to the k-mean clustering method and based on the utilities additives discriminates method, were the most desirable and were selected for portfolio formation.