فصلنامه مدلسازی اقتصادی
سال شانزدهم شماره 2 (پیاپی 58، تابستان 1401)

The impact of the development of information and communication technology on the labor market and social security has been the focus of international labor and social security organizations. This study examines the impact of ICT on Social Security Resources in the context of Iran’s economy during the period 1999 to 2019, using the Stochastic Dynamic General Equilibrium (DSGE) model, focused on duality of labor market (formal and informal).  The results of the study show that the development of information and communication technology affects social security resources by changing the structure of employment. A survey on the variables response to the positive impulse of ICT shows that the further increase in job opportunities in the informal sector provides more access to jobs in this sector and increasing in the participation rate, the number of informal workers increases. The finding show increasing in informal employment causes an increase in the lost resources of social security. Based on the results, it is suggested that policymakers and insurance funds develop flexible programs in order to expand insurance coverage and support informal workers with the participation of employers and the government.

Tax avoidance reduces the outflow of cash from the company to the government, which from the past to the present is considered a value for shareholders. Therefore, considering such a necessity, the present study, in order to help tax administrators, examines the effects of investment inefficiency in the labor force on corporate tax avoidance activities for a sample of 64 export companies in Iran during the period of 2009 to 2019. For this purpose, in two stages, Dynamic Panel Data method and Generalized Method of Moment (GMM) estimator were used; in this way, first, the inefficiency of investment in labor was estimated and then its effect on corporate tax avoidance was estimated. The results of estimating the research model indicate the direct effect of investment inefficiency in the workforce on corporate tax avoidance. In addition, the results showed that the market value and size of the company are associated with a direct and inverse effect on tax avoidance, respectively. Thus, increasing ambiguity, a weaker control environment, and a reduction in expected cash flows due to inefficient investment in the workforce provide opportunities for the company's manager to increase tax avoidance, and tax policymakers need to pay special attention to this issue.

The purpose of this research is to investigate the relationship between crude oil prices and the stock market index of Iran in the period from September 2009 to December 2020. For this purpose, by using wavelet coherence approach based on continuous wavelet transform, the relationship between the yield pair series of Brent crude oil price-total stock index, WTI oil price-total stock index and OPEC oil price-total index of Tehran Stock Exchange has been investigated .The results of this research show that the dependence between the above pair of time series increases with the increase of uncertain conditions such as the increase of sanctions, the withdrawal of the United States from the JCPOA, and the corona pandemic in the medium and long term. Therefore, investors can adjust their investment portfolio in the long and medium term based on the conditions governing the country and their investment goals.

This study estimated the effect of private and government investment on the growth of the health sector in Iran with the ARDL approach, 1981-2019. The selected indicators were estimated in two selected indicators: health expenditure and health index (life expectancy). The estimation results of the model show that the increase in economic growth, causes an increase health expenditures and the increase of private sector investment in the health sector, causes an increase health expenditures and the increase of private sector and government investment in the health sector, improve the Health index. In the long term, the rate of AIDS and the inflation rate have a negative effect on health expenditure and health index; and the literacy rate, the urbanization rate, the real exchange rate, and the real interest rate have a positive effect on health expenditure and health index. The results of this study, consist with other researches, showed that by focusing on investment, the growth of the health sector in Iran improves. The findings of this study can be used to implement a more efficient policy in the way and type of investment in the health sector.

The most important instrument of the government to finance public expenditures and to improve the distribution of tax revenues is tax. High reliance of government on seignorage can reduce the role of taxes in correcting the inequalities. Improving the political variable of the voice and accountability by less reliance on seignorage and more reliance on taxes can improve income distribution.The main purpose of this study is to investigate and test this hypothesis with the help of data from selected OECD and D8countriesperiod 2018-2008 using the fully modified least squares method (FMOLS). The results of model estimation showed that the political variables of accountability can improve the distribution of income in the studied countries by reducing the government's reliance on seignorage.