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The phenomenon of tax evasion has been always one of the most major issues among economists due to it's devastating effects on the economy and the process of economic development. Many scholars have always sought to provide solutions to reduce and limit tax evasion. The introduction of the VAT system can be seen as a milestone in the area of economic transparency and tax evasion, which refers to counteracting this phenomenon through reforming the structure of the tax system. In the present study, the effect of VAT on the tax evasion phenomenon has been discussed. For this purpose, the research hypothesis has been tested for data from 28 OECD countries in the period from 2013 to 2002 using generalized moments method. The results of the estimation show that by expanding the value added tax, the tax evasion phenomenon also decreases. Also, agricultural value added has a positive effect on tax evasion, while the effect of inflation and rule of law are negative. Therefore, in order to deal with the phenomenon of tax evasion, attention to institutional factors, along with attention to economic factors such as the structure of the tax system, is proposed.
 

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For decades, researchers of tax systems and tax payment have investigated the factors affecting taxpayers' inconsistent behavior. Several experimental and survey results obtained by these researchers have identified the characteristics of non-committed taxpayers and factors affecting tax evasion, as tax revenues are seen as the main source of income in financing government expenditures.In this study, we aim to identify the key drivers of tax evasion in Iran with a future research approach. In this research, using the Delphi method and the participation of 31 experts, the results were analyzed in the environment of MicMac software, and then these factors were determined based on the degree of importance and uncertainty, prioritization and the most critical factors, and to identify the drivers. Key features of the software (Micmac) have been used. The results according to the matrix of direct influence in the output of this software indicate that the index of weak understanding of organizational ethics and social responsibilities in the ethical decision-making of professional accountants, weak trust in the government and legal requirements based on the possibility of detection and punishment, in the rank The first to third direct and variable influence of the lack of tax culture in the society has been placed in the first rank of indirect influence.