نشریه اقتصاد و الگوسازی
پیاپی 51 (پاییز 1401)

The main goal of this research is to examine and test the asymmetric effects of monetary policy on the production of industries and mines. For this purpose, hidden cointegration analysis and Autoregressive distributed lag (ARDL) approach in Iran's economy have been used in the period from 1353 to1399.Hodrick Prescott filter was used to extract the positive and negative impulses of the liquidity variable. Then, the effects of positive and negative impulses of the variables were investigated separately on the positive and negative impulses of the production of this sector with latent cointegration analysis. In the last step, the long-term relationship between the variables is checked and the long-term coefficients are calculated using the auto-regression model approach with non-linear distribution intervals and the bounds test. The results showed that there is a hidden co-accumulation between the time series of M_2 and production in the industrial sector.The results showed that there is a hidden cointegration between the time series of M_2 and production in the industrial sector. So that the positive components of the M_2 and production in this sector have a long-term relationship with each other, as well as their negative components. Also, the effect of the positive shocks of M2 is greater than the negative shocks of this variable. Therefore, the existence of asymmetry in monetary policy was confirmed.

The COVID-19 pandemic produced an enormous impact on human society with multiple health, social and economic effects. The impact on international trade has been enormous. Thus, the World Trade Organization (WTO) states that “the COVID-19 pandemic represents an unprecedented disruption to the global economy and world trade, as production and consumption are scaled back across the globe”. Thus, the spreading of the general pandemic COVID-19 has caused significant changes in the volume and structure of trade between countries. This essay examines the trade ties between Iran and other countries in the world trade network before and after the outbreak of the Covid-19. To this end, using the data provided by 149 countries during 2018 and 2020 and also drawing on Network Analysis Method and Leiden’s Community Detection Algorithms, and then utilizing the indicators of centrality and density, the county's position in the Asian-African trade complex was put to examination. By comparing the structure of the trade network during the 2018 and 2020, the results show that with the outbreak of the Covid-19, the structure of trade relations and the position of most of the countries, especially Iran, has been severely affected, to an extent that the indicators of centrality of strength, closeness, the Eigen vector and density indicator have decreased in 2020 compared to 2018, which demonstrates the downfall in the share of trade and the decline in the importance and position of countries, especially Iran.

this study examines the factors affecting the horizontal diversification of non-oil exports in the short and long term, with using the autoregression method with distribution intervals and using the data in 1995 to 2021 years. First, a new index of export diversity is designed, which is more comprehensive than the existing indices and has advantages. Then, this innovative index, for Iran and the major export destination countries, calculates and determines the position of Iran's export diversity among these countries.The results of the model estimation indicate that the variables of non-oil foreign direct investment and exchange rate do not have a significant effect on the export diversity index in the long term. Research and development costs and non-oil gross fixed investment have a positive and significant effect on export diversity in the long term. The variable of granting facilities to the non-governmental sector has had significant negative effects on the dependent variable in the long term. The embargo has also had a significant negative impact on export diversity in the long term.According to the results of the model, increasing the government's research and development budget and granting loans to export-oriented companies with the aim of enhancing research and development operations in these companies and investing in the non-oil sector can be a way to improve export diversification.

There are Limited domestic studies have analyzed household income and expenditure survey (HIES) data and determined the factors affecting household food expenditure. So, the analysis of the changes that have occurred in the consumption behavior of households is highly necessary, due to the many shocks, including the economic sanctions since 2018 and the outbreak of Corona in 2020, brought to Iran's economy. The current study has addressed this important issue. In this research, quantile regression was performed concerning 9 quantiles from 0.1 to 0.9 for 2-year 2016 as a relatively stable year and 2021 as a year after the occurrence of shocks on the summery of urban HIES data.Based on the obtained results, among the 16-variable considered in 2016, the gender, education level, and marital status of the head of the household and per capita subsidy received by the household members and in 2021, literacy status, education level, and marital status of the head of the household in None of the quantiles had a significant impact on household food expenditure. Therefore the household's head's gender and the per capita subsidy received by the household members, which were not considered in 2016, became significant in 2021. The noteworthy point is the growth in the per capita income coefficient in 2021 compared to 2016, which indicates the increase in the sensitivity of food expenses to income and the reduction of household food expenses sticking to their previous values, which can demonstrate the decline of the household's economic potential during this 5-year.

Energy, as one of the important inputs of production, has a special place in the economic development and progress of every country. Therefore, checking the price of gas can be important for Iran and countries with oil and gas resources. In addition, based on the past trend of gas prices in the world market, we can conclude that gas prices have always been affected by global oil prices. On the other hand, considering the role of specialized labor in the two oil and gas sectors of the studied countries, it is important to be able to determine the simultaneous effect of the gas price and the total factor productivity on the transfer of labor between these two economic sectors. To achieve this goal, this research used the dynamic computable general equilibrium model (DCGE) and the social accounting matrix of 2014, and according to the dynamics of the model, the change process has been predicted for the years 2022-2030. The results indicate that, with the increase in the price of gas and the total factor productivity, skilled and unskilled labor is transferred from the oil sector to gas for Iran and the Gas Exporting Countries Forum, and this trend is also in the long term. Also, this impulse led to an increase of capital and land used in the gas sector of gas exporting countries by 88.08 and 57.35% respectively, and in Iran, capital and land used in the gas sector by 88.08 and 57.35% respectively. 4.59 and 4.84% were estimated..

Considering the importance of the impact of income inequality on economic growth, this study examined the causal relationship between income inequality and economic growth and the hypothesis of income inequality's inconclusive and asymmetric effects on economic growth in 25 developing countries from 1996-2018. The Panel Granger causality test results showed only a unidirectional causal relationship between income inequality and economic growth from income inequality to economic growth. Also, the study of the hypothesis of the asymmetric effect of income inequality on economic growth using panel threshold regression (PTR) by Hansen (1999) showed that income inequality affected economic growth in the form of a two-regime structure (with a threshold value of 48% for the Gini coefficient), although the findings do not confirm the existence of an inverse U relationship between these variables. Therefore, it can be said that our findings confirmed Barrow (2000)'s view that "income inequality weakens economic growth in developing countries." Therefore, based on the findings of this study, it is recommended: first, contrary to classical economic theory, developing countries need to implement policies to reduce income inequality not only to establish social justice, but also to increase economic growth. Secondly, because of the unidirectional causal relationship between income inequality to economic growth in developing countries, policies to increase economic growth in these countries do not lead to improvement in income distribution. Therefore, these countries must implement independent policies to improve income distribution.