Journal of Tax Research

Introduction

The phenomenon of tax evasion is a socio-economic problem that is of concern both from the perspective of the government and the perspective of individuals in society; because on the one hand, it causes problems in financing governments and on the other hand, it plays an important role in the well-being of societies and increases the well-known problem of free riding. A selfish citizen uses a public good without contributing to its cost, and this is in contradiction with social justice. Tax evasion causes inefficiency and misallocation of government spending on health, education, social security, etc. One of the issues that should be considered in designing the property income tax law is blocking the paths through which tax evasion is possible; the less the possibility of tax evasion is reduced, the easier the objectives of the property income tax in controlling speculation will be achieved, and speculators, as the main factor in increasing housing prices, will not be able to evade paying this tax. Given that real estate transactions are subject to capital gains tax upon official registration, tax evasion will be possible through granting a power of attorney, using ordinary documents, or through a deed of sale. Therefore, it is necessary to make tax evasion impossible by blocking these three paths. Accordingly, the main goal of this research was based on modeling the phenomenon of tax evasion in capital gains tax in the housing sector using a game theory approach.

Methods and Material                                             

Game theory attempts to model situations where individuals' interests conflict. The main goal of game theory is to provide a perspective that players should act wisely and think deeply about their actions before taking action and then choose an action that is in their best interests. Game theory can be very useful if the number of players (agents) in conflict is limited, because in this case, the behavior of each player has a significant impact on the income of other players. The ultimate goal of this knowledge is to find the optimal strategy for players. Based on the classification of tax evasion cases, the set of players (taxpayers and the government), their strategies (taxpayer strategies: tax compliance or tax evasion; government strategies: audit or non-audit) and the set of consequences for the players in each strategy are determined. Given that in each of the tax evasion case categories, the taxpayer's strategies for tax evasion and therefore the consequences and income of the government and the taxpayer will be different. Two game theory models can be designed for each category: 1) declaring real income, 2) declaring unreal income (under-declaring). It is worth noting that the government's strategy in all models is the same and includes two states: 1) conducting an audit, 2) not conducting an audit.

Results and Discussion

Given the importance of the housing market and its consumer demand in society, the main mission of this research was also focused on designing a tax evasion game in the capital gains tax in the housing sector. In a way that, based on strategic interactions and the framework for collecting capital gains tax in the housing sector, four game models were designed between the Tax Administration (government) and taxpayers;

• Transaction concealment: This means not registering the transaction in the country's land and property registration offices and is done informally with collusion between the buyer and the seller. It should be noted that this type of tax evasion has negative consequences and many risks for the property buyer.
• Understatement of the sales price: This means that the property seller declares his declared price of selling the property lower than the actual price in order to pay less tax. This is also done with collusion between the buyer and the seller of the property.
•  Overstatement of purchase price: This means that the seller of the property declares the declared price of the property higher than the actual price in order to pay less tax when selling the property.
• Understatement of sale price and overstatement of purchase price (simultaneously): In this case, overstatement of sale price by the seller of the property and understatement of purchase price by the buyer of the property occur simultaneously.

In all four tax evasion game models, the government's strategy is to conduct an audit (assessment) and not to conduct an audit (non-assessment). In contrast, the taxpayers' strategy is either tax compliance or tax evasion. Considering these four types of game models and the strategies considered for the two players (government and taxpayers), the income of each player was determined and solved based on the mathematical methods used in the research of Korchen (1992).

Conclusion

In order to evaluate and analyze the results obtained from tax evasion models, using real housing market data, scenario development and empirical estimation were carried out. So that, considering 5 main and basic assumptions, different cases including increase and decrease in housing price growth, penalty rate and audit costs were designed, and the probability of tax evasion, probability of government assessment, expected outcome of taxpayers and expected outcome of the government were examined and compared for different cases. In total, the comparison of scenarios in four tax evasion game models showed that;

• The highest probability of tax evasion in all six scenarios studied is related to the tax evasion model of overstatement of purchase price and the lowest probability of tax evasion is related to the simultaneous model of overstatement of purchase price and understatement of sale price.
• In all six scenarios studied, the probability of government assessment in the models of understatement of selling price, overstatement of purchase price, understatement of selling price and overstatement of purchase price is the same, but in the transaction concealment model it is obtained to a lesser extent than in the other three models.
• The expected outcome for taxpayers in all six scenarios was negative.
• The expected outcome for the government in all six scenarios designed was negative only for the transaction concealment model.