تأثیر مالیات بر معادلات ساختاری بخش تقاضای اقتصاد کلان ایران با استفاده از رویکرد بیزین

Introduction: Taxes and tax revenues are one of the most important tools for stabilizing governments. In macroeconomics, the impact of taxes is examined in terms of their impact on total consumption and aggregate demand. The role of the tax system in an economy is based on economic, political, and social objectives, while the political and social objectives are more influenced by the economic objectives of taxation, considering the monetization aspects of the government and its impact on the other sectors of the economy. Since the tax size plays a key role in providing the revenue requirements of the governments, implementing any tax policy requires good insight into how the economy must perform to achieve the optimum size of tax revenue with minimum inefficiency. Implementing any tax policy to provide the revenue sources needed for government spending can have different effects on economic growth and income distribution. In this regard, many studies have shown that, among the tools of government fiscal policy, construction expenditures and taxes can have significant direct and inverse effects on economic growth respectively, while consumption expenditures do not have a significant effect on economic growth.
Methodology: In general, because of their effect on the return on physical and human investment, taxes can affect economic decisions and ultimately the growth rate of the economy as a whole. Given the current state of the Iranian economy, which is accompanied by low economic growth, dependence on oil, the existence of inequality in income distribution and change of the population ratio in favor of the retired and the disabled, reducing the economy's dependence on oil revenues and increasing the government reliance on tax revenues seem more than necessary. For this purpose, in this study, the Bayesian approach and Klein's basic model were used to study the demand structure of Iran during the years1989-2016, which provides the possibility to appraise the impact of policy variables on aggregate demands. The advantages of this method are due to the use of non-data to obtain a clear picture of the state of the economy as a result of economic change.
Results and Discussion: According to the results, the effect of taxes on reducing consumption and aggregate demand is relatively small. Therefore, as it seems, raising taxes will not reduce production. This is only a short-term consequence of tax increases. On the other hand, raising taxes by stimulating people's tendency to save can improve the country's long-term growth conditions. Also, the use of appropriate increases in tax rates means that the methods of financing the inflation deficit are not used and, thus, the value of the national currency is not weakened. In addition, financing through taxes reduces the country's dependence on foreign countries in order to cover the capital deficit in the balance of payments. The results of this study indicate that, in order to cut the government's dependence on oil revenues, the government could rely on tax revenues given that the total effect of taxes on income and consumption is not high; it is better and quicker to reach the desired income (an increase of one trillion Rials in taxes will lead to a reduction in consumption of just about 200 billion Rials). Moreover, the results indicate an increase in the total expenditures by the government to 1,000 billion Rials will increase the consumption to about 290 billion Rials. According to the results, the effect of taxes on reducing consumption and aggregate demand is relatively small; therefore, as it seems, raising taxes will not reduce production. This is only a short-term consequence of tax increases. On the other hand, raising taxes stimulates people's tendency to save, which can improve the country's long-term growth conditions. The use of appropriate increases in tax rates means that the methods of financing the inflation deficit are not used and, thus, the national currency is not devalued. Financing through taxes also reduces the country's dependence on foreign countries in order to cover the capital deficit of the balance of payments. According to the results, the ratio of taxes to GDP is always lower than the ratio of current government expenditures to GDP. This indicates that, as governments have grown, the share of government revenues from taxes has been very low. Therefore, to maintain this ratio, it is necessary to either increase government revenues or reduce government expenditures. Of course, regarding the government expenditures, the difference between the current and development expenditures must be taken into account. This is because the reduction of construction costs and insufficient growth in infrastructure can reduce economic growth in the future.
Conclusion: Due to the difference in the final tendency for consumption among different segments of the society, the adoption of any tax policy or the imposition of any tax revenue does target the income of a segment of the society. Therefore, different types of taxes can have different effects on the private consumption of the society, and recognizing it will help the country's tax policymakers to increase the efficiency of different types of taxes. Given the recession-inflationary conditions of the Iranian economy, which is accompanied by low oil-dependent economic growth, rising prices and inequality in income distribution, reducing the economy's dependence on oil revenues and increasing government dependence on tax revenues seem more than necessary. Utilizing the maximum tax power of the country and increasing the tax base to improve the performance of the country's tax system will make it possible to provide goods and public services desired by citizens by relying less on oil revenues. Since the effect of the total taxes on income and consumption is not significant, in order to break the government's dependence on oil revenues, it is possible to act better and faster to achieve the desired revenue. However, the effect of the exogenous increase of taxes by the government on the total expenditures should not be overestimated. Given the low impact of consumption taxes, it is highly recommended to determine the optimal rate of consumption tax from the revenues of this type of tax to build the corresponding infrastructures. Moreover, appropriate resources and increased government spending on development should serve to reduce the role of oil revenues from the budget to create the conditions for better economic growth in the future.