Principle of Distribution of damages based on extent of the effect of actions; Legal basic, conditions of executive rules and it`s domain in Iranian law

If two or more person cause damage, the loss is divided between them according to legal rules. By one of these rules, each person is responsible to the extent of the effect of his action. This rule is followed in the Islamic Penal code approved in 2013. In addition, by provisions of that law, it seems that the division of damages based on the degree of effect of acts is the principle of division of civil liability in Iranian law: according to Article 526, if the effect of the acts of the perpetrators is different, they are responsible for the effect of their acts and accordingly, damages should be apportioned differently. Also, according to Article 527 that law, if the effect of the behavior is equal, the responsibility is divided equally. It is necessary for the implementation of these provisions that the judge conducts sufficient research on the amount of each agent's behavior. So, if he decides without investigating, he has violated the law. Thus, if by the necessary research, the degree of causation of each agent is not known, based on the principle of equality, the responsibility of all agents is equal.
Although these rules is considered doubtful in legal thought, the judicial procedure has been successful in enforcing the law. The unanimous decision No. 799 of the General Board of the Supreme Court confirms this claim. That decision refer to the partial distribution of financial losses based on the degree of causation of each agent. Thus, in the case of acquiring property through illegal ways, everyone has caused loss equal to the money that acquired illegally. Also, in the case of other types of damages, the extent of the impact of the behavior of each of the agents could be determined with evidentiary reasons such as expert opinion.