Aggregation Bias On The Trade Effect Measurement Of TBT In Agricultural Products

The World Trade Organization (WTO) established should become the effective institutional arrangement regulating international trade disputes and frictions, but the fact is not just as wishes. In the first decade of the21st century with the tariff barriers gradually faded, technical barriers to trade (TBT) as the representative of the non-tariff barrier is becoming the disputes fuse of many products in international trade Since agricultural trade itself involves pesticide residues (MRs), heavy metals and other issues are more vulnerable to the impact of TBT. And research on the measurement of TBT trade effects is the a prerequisite of reasonable to solve trade disputes. Current studies on the trade effect of TBT gradually broke through the original simple rough analysis framework against the new field of international trade and econometrics. The measurement of the trade effect of TBT mainly involved the use of aggregated data model and subdivision data model. However, there are obvious differences between them in most cases. Especially the individual heterogeneity represented in disaggregated data often be masked out in the data aggregation process, resulting in a aggregation estimation bias.Such estimation bias will bring serious misjudgment on the effect of TBT which may distract and mislead the exact implementation of foreign trade policy.Therefore this paper will study the effect of TBT in agricultural trade by the aggregation and disaggregated data model from the perspective of aggregation bias and fully research on the causes of bias, bias of measurement and inspection. Firstly, this paper begin by reviewing the original technical approach of the TBT trade effects measurement and aggregation bias theory, and then deduce an unified analysis framework. For the aggregation bias theory, we put forward three kinds of aggregation form, three types of bias, two causes of aggregation bias and three kinds of test methods. Further study found that endogeneity of the disaggregated data model and aggregation process are the root causes of the aggregation bias. Then to fully prove the above research conclusion and find the aggregation bias characteristics in the different situations, we specially carried on the detailed numerical simulation, and study the inherent relationship between endogeneity and aggregation bias. Finally, we use the theory of aggregation bias to carried out the empirical analysis on the real effect of TBT in agricultural trade.and then provide an effective policy recommendations on China’s agricultural trade how to respond accurately and differently to foreign technical trade barriers.Through the study in this paper, we get the following conclusion.(1)The effect of TBT in agricultural products trade showed in the aggregated and disaggregated data levels are different This kind of difference result from the individual heterogeneity.(2)The aggregation bias of the measurement on the agricultural trade effects in TBT is determined by the endogeneity of the disaggregated data models themselves and the endogenous factors in the process of aggregation.(3)Based on the aggregation bias measurement and test in different aggregation form and different aggregation path,we have found the really true causes and given an accurate positioning in the process of the measurement on TBT trade effects of the representative agricultural products trade.This dissertation revealed the root cause of the aggregation bias, and provides new methods and analytical framework to analyze the aggregation model parameter estimation. And also it could be a technical support for improving economic data analysis accuracy. In addition, the numerical simulation method provides an ideal and effective means of experiment for aggregation bias research through systematically to show the relationship between the endogeneity and aggregation bias. Through this study also provides a theory bridges connection with aggregation and disaggregation model parameter estimation, further enriched and strengthened the theoretical basis of TBT trade effect study, but also to broaden the perspective of the research of technical barriers to trade.