Under the background that the power to collect social security levies is fully assigned to the tax department, since the tax department does not have a strong awareness of the main responsibility for fulfilling social security laws, the efficiency of the tax department in responding to social security laws and regulations is a matter of concern. The lack of response efficiency will directly affect the improvement of the collection and management level, making it deviate from the expected optimal level. Based on the introduction of the Social Insurance Law, using the national tax survey data from 2007 to 2013 and the DID method, this paper compares the difference between the response efficiency of the social security full responsibility model and the tax agency model.

The study finds that the response efficiency of the social security full responsibility model to the Social Insurance Law is significantly better than the tax agency model. The improvement of the response efficiency of the social security department is mainly reflected in private enterprises and non-labor-intensive enterprises, reflecting the expansion effect of the law. Further research finds that the information exchange between the social security department and the tax department can effectively compensate for the response efficiency of the tax agency model. The results show that, under the background that the tax department is responsible for the social insurance collection authority, improving the main responsibility of the tax department in collection authority, improving the function performance efficiency of the tax department by doing a good job of corresponding incentives and constraints, and strengthening the construction of information exchange between the social security department and the tax department, will help to break the institutional barriers that restrict the development of social security undertakings.

The contributions of this paper are mainly as follows: First, from the perspective of collection and management departments, it examines the differential response efficiency of different social security levies collection models with the central unified regulations. Second, by analyzing the institutional barriers that restrict the response efficiency of the tax agency model, it deeply examines the important role of information sharing in cross-department collaboration, and provides policy guidance for effectively alleviating the loss of synergy efficiency in cross-department collaboration. Third, it helps the government to better promote the reform of transferring the responsibility of social security levies to the tax department.