| COVID-19 has caused a huge impact on the economy of China and the world,therefore,how to enhance the comparative advantages of the pharmaceutical industry and improve the independent innovation capability of pharmaceutical product research and development has become an important topic of concern to many scholars.This paper uses Chinese pharmaceutical products as a carrier to study whether trade intervention policies can play a role in improving comparative advantage.On the basis of David Ricardo’s theory of comparative advantage,the construction method of policy intervention index is used to grasp the current situation and development of drug-related trade policies.First,the theoretical basis and principles of measuring the degree of policy intervention are introduced.In equilibrium,the net export capacity of a country’s products should match its level of comparative advantage,If the trade pattern of this product deviates from the equilibrium state,the degree of the two deviates constitutes the“Policy intervention index”.Then,the basic measurement indicators and measurement methods for constructing the policy intervention index are described,and the dynamic evolution diagram of the import and export trade model is drawn according to the indicators.Based on this,the trade policy characteristics of China’s pharmaceutical product import and export are analyzed and summarized.Finally,the necessary data processing is carried out,and the short-term and long-term Granger causality test based on the error correction model is further carried out.The empirical analysis part adopts the annual trade data of China’s pharmaceutical product import and export from 1985 to 2020,and selects the policy intervention index of import(HMcp),the policy intervention index of export(HXcp),and the revealed comparative advantage of export(RXcp).A Granger causality test model based on the error correction model is established.The step-by-step solution to establish the optimal error correction model involves three key issues:one is to determine which is better between the linear and nonlinear models;the second is to determine the optimal lag period of the model;the third is to clarify the form of the additional term of the optimal VECM.The first and second problems are solved by the unconstrained Vector Auto Regression（VAR）model;the third problem is solved by the Johansen co-integration test.At the same time,the relationship between the comparative advantage of China’s pharmaceutical product export and the import and export policy intervention was investigated separately,and the robustness test was carried out to verify the rationality of the model setting and the robustness of the empirical results.The results show that intervention policies that restrict the import of pharmaceutical products in the short term have a negative impact on the comparative advantage of exports,while intervention policies that promote the export of pharmaceutical products have a positive impact on the comparative advantage of exports.In the long run,there is no evidence that the import and export intervention policies of China’s pharmaceutical product trade can enhance the comparative advantage of China’s pharmaceutical products in the long run,proving that the improvement of the comparative advantage of pharmaceutical product exports is at least in the long run.intervening.In addition,the export policy intervention index(HXcp)is the long-term Granger cause of the import policy intervention index(HMcp),and HXcphas a long-term positive effect on HMcp,that is,there is a linkage effect between import and export policies,and the degree of export policy intervention The improvement of import policy will increase the degree of import policy intervention.Therefore,in the process of trade policy formulation and implementation,the impact of a certain intervention policy on comparative advantage should not be considered alone,but various factors and variables should be taken into account.For example,the introduction of a new intervention policy will affect the original What is the impact of the policy effect,and whether the short-term and long-term effects of the intervention are different. |
