[The central bank issued a policy stance on the RMB exchange rate: the international assessment methods are generally immature and lack convincing consensus conclusions] October 8th, the People's Bank of China released a policy stance on the RMB exchange rate. It pointed out that the relevant international assessment methods are generally immature and lack convincing consensus conclusions. After long-term development, many types of equilibrium exchange rate assessment models have been derived from academic research. Each model relies on different theoretical foundations, data sources, parameter settings and measurement methods. In addition, the factors affecting the exchange rate are complex. It is very difficult to objectively measure the so-called equilibrium exchange rate level. The results of different assessments often vary greatly, and it is difficult to form a convincing consensus conclusion so far. Using the results of the IMF's External Balance Assessment (EBA) as the basis for the undervaluation of the RMB exchange rate is a misinterpretation and misuse of the assessment results, and lacks the necessary professional understanding of the exchange rate. In fact, the external balance assessment is mainly positioned as an external imbalance analysis tool rather than a specialized equilibrium exchange rate measurement model. It includes three modules: the current account model, the real effective exchange rate model and the external sustainability method. Among them, the current account model is the most core, aiming to measure the current account gap status of each country through econometric models. On this basis, the degree of deviation of each country's real effective exchange rate is further calculated. Implicit in this approach is the assumption that there is a linear causal relationship between the current account and the real effective exchange rate. The IMF has also specially established a real effective exchange rate model, including two calculation methods: the index method and the level method. The evaluation results of the above three methods are very different, and even opposite in direction, indicating that the credibility of a single method is not enough. The IMF assesses the real effective exchange rate and should not be misinterpreted as an opinion on the nominal exchange rate. The real effective exchange rate is jointly determined by the nominal effective exchange rate and domestic and foreign relative prices, and more reflects the influence of macro and economic structure levels such as the supply and demand relationship in a country's economy. However, some opinions intentionally or unintentionally guide the results of the IMF's external balance assessment to the nominal exchange rate of the RMB, or even the exchange rate of the RMB against the US dollar, and use them as the "official basis" for exchange rate accusations. In fact, the IMF's policy recommendations to China are mainly structural adjustment policies such as actively expanding domestic demand, rather than promoting the appreciation of the RMB exchange rate. It should be noted that external balance assessment has the characteristics of relatively transparent methods and continuous iterative improvement, but it also faces challenges. For example, the latest external balance assessment model spans 40 years and covers 52 economies, increasing the amount of sample data. During this period, the global economy and the industrial structure of various countries have undergone major changes. The model does not distinguish between the structural changes and differences in the time dimension and country dimension of the sample in parameter setting and measurement testing. For another example, after adjusting variables in the existing model, the evaluation results will change significantly, indicating that the robustness of the model can be further enhanced. In addition, the model residual value is large, indicating that the unexplained part of the model is high, and there is room for improvement in the overall explanatory power. Generally speaking, the results of the econometric model can be used as a reference for academic discussions, but they cannot be a strict basis for evaluating a country's external imbalances and equilibrium exchange rate levels.