فصلنامه تحقیقات مدلسازی اقتصادی
سال سیزدهم شماره 49 (پاییز 1401)

Applying a favorable tax system has important conditions such as justice and efficiency, therefore, consumption tax and income tax will comply with the principles of benefit and ability to pay. In this regard, value added tax is known as the most important innovation of the 20th century in terms of tax collection on consumption. Since increasing government revenue is one of the important goals of imposing this type of tax, the government has tried to determine the rate of this type of tax effectively and efficiently. Disproportionate increase in value added tax rates can have negative social effects on inflation, economic growth, income distribution, and general well-being in society. It may also have disruptive effects on other variables and sectors of Iran's economy. To manage the rate increase, one approach is to simulate and examine its consequences and effects on macroeconomic variables in the form of a multi-regional calculable general equilibrium model (MRCGE). Three different scenarios were applied and examined to simulate the shock effects of the increase in the value-added tax rate (12% , 15% , and 20 %) on four macro variables of Iran's economy: inflation, gross domestic product, consumption, and investment.  The simulations were conducted at the country level using a multi-regional calculable general balance model, known as the ORANI-G Iran model, using the 2016 input-output table and regional accounts of the country. The results indicate that the effect of increasing the tax rate on value-added will increase inflation and investment and decrease GDP and consumption.

Monetary policy modeling is one of the important areas in macroeconomics, which has been expanded after the pioneering study of Taylor (1993) in the framework of the central bank's reaction function. By applying new econometric approaches, economists try to answer the controversies in the literature and provide new implications by evaluating the monetary policy and its relationship with macroeconomic stability. In this regard, the current research has used the continuous wavelet transform and its tools to investigate the relationship between monetary policy and the production gap, inflation deviation and the gap in the foreign exchange market in Iran's economy. The results show that in the period of 1989-2022, the central bank only in the short term (less than one year) puts the output gap under its target or affects it arbitrarily. This is important for the deviation of inflation from its long-term trend in the short-term and medium-term (1-4 years). Due to the intertwining of the monetary policy and the currency market, which is due to the lack of independence of the central bank, the tendency to suppress the exchange rate and the contagion of imbalances to the monetary base, the relationship between the monetary policy and the gap in the currency market is unstable.The information and analysis presented in the field of time-frequency, taking into account the developments of Iran's economy, can be useful for those interested in this field.

The state of development of technology in today's world is such that the development process and the future of the world in the field of technology cannot be accurately predicted. In the meantime, blockchain technology has been highly regarded as a revolutionary technology. This technology is a protocol that allows information to be exchanged directly between contracting parties in a network without the need for intermediaries. Blockchain has been one of the most important technology trends in recent years, and banking is one of those sectors that many experts believe will accept major changes from blockchain technology. Considering the revolutionary impact that blockchain technology can have on the banking system, it will be very important to examine the impact of this technology on the banking system, which represents how to create, present and acquire value in this sector. The purpose of this research is to investigate the impact of this technology in the banking system. In order to achieve this goal, the method of data collection is the type of document-library research and sample statistics, and it is quantitative-qualitative in nature, and the method is a survey, and the tools used are questionnaires and field observations. According to this research, it confirms the effectiveness of blockchain technology on the banking system. Finally, considering that blockchain technology will challenge almost all the core sectors of the banking system, it is necessary for banks to adopt a suitable strategy to deal with the threats and use the opportunities resulting from this technology.

The unmanaged control of liquidity growth has always been the concern of policymakers due to its negative consequences. Recently, policymakers have focused on the needing to control the liquidity growth. One of the liquidity drivers is the government borrowing from the central bank. In this regard, governments have concerned for the issue of not borrowing from the central bank since the 2000s onwards. Although governments are limiting themselves for this borrowing, they force banks and financial institutions to borrow from that source. For this purpose, this study designs a macroeconomic model by including the net debt of the public sector to the central bank as well as to banks and financial institutions via the government's financial balance channel. This model shows the relationships of economic variables in the framework of a stochastic dynamic general equilibrium (DSGE) model, considering nominal and real frictions. The results confirm the reliability of the model for simulating the economy of Iran after determining the input values and calibrating the parameters of the model using the Iran's economy data during 2000-2020.  The findings from the research data show that the net increase in government sector debt to banks and non-banking credit institutions has a positive effect on investment, in such a way that new liquidity by the government obtained from institutions and banks It has been produced in the form of new deposits at the disposal of the department. The net impulse of public sector debt to the central bank causes an increase in consumption in the utility function and the total consumption of a combination of public goods and services provided by the government as well as private consumption goods and services. Also, the net impulse of public sector debt to the central bank causes an increase in inflation and a slight growth of production, and the net impulse of public sector debt to banks and credit institutions increases inflation and stimulates production.

Climate change has emerged as a significant global challenge, with its impact increasing rapidly in recent decades. The consumption of fossil fuels, which leads to the emission of greenhouse gases like CO2, is a major contributor to climate change. Iran, ranked as the sixth most polluted country in the world, emitted a staggering 745 million tons of CO2 in 2020. Notably, the power plants sector in Iran accounts for roughly 30% of its total carbon emissions. As a result, the main objective of this paper is to engage in long-term planning for electricity supply and demand in Iran, aiming to reduce carbon emissions in line with the country's obligations under the Paris Agreement. To achieve this goal, we utilized the MESSAGE model to design an electricity generation system that takes into account the potential of renewable sources from 2021 to 2050. Additionally, the ARDL model was employed to estimate electricity demand under various scenarios, including subsidy reforms. These predictions were then incorporated into the long-term planning process for Iran's electricity supply system. The findings of the ARDL model highlight that the subsidy reform strategy leads to a 10% decrease in electricity demand throughout the planning period, indicating effective control over the demand side. On the other hand, the MESSAGE model's findings reveal that Iran's ability to fulfill its responsibilities under the Paris Agreement heavily relies on the utilization of renewable potentials across different regions in power supply planning. While carbon dioxide emissions in Iran's electrical sector are not expected to be reduced in the near future (2020 to 2030). However, in the long term (2040 to 2050), significant reductions in CO2 emissions can be achieved. According to the findings, if the electricity system in Iran is designed in accordance with a chosen scenario that incorporates green technologies and subsidy reforms, the share of renewable technologies can increase from 6% in 2020 to 15%, 50%, and 78% in 2030, 2040, and 2050, respectively. Consequently, carbon emissions in the power generation sector can be reduced by 20% and 54% in 2040 and 2050, respectively, compared to 2020 levels.