Statistics Bureau Officials Wrote That CPI Was Undervalued.

　　 National Bureau of Statistics The website posted the deputy director of the city Department on the evening of 10. Xiao Lin pan Signed article, responded to "the Academy of Social Sciences report" China CPI It was reported that people were underestimated 7% in 5 years. The article thinks media coverage The conclusion is subjective inference. Facts do not agree with each other. 。 The media did not verify the reliability of the report, and the headlines were misleading the public.

The article claims that the mathematical model is only an analytical tool, and is not suitable for directly producing statistical data. The conclusion that the author has deduced from the mathematical model that he is undervalued by 7% is merely a statement of one family, and is not the consensus of mainstream experts and scholars. Without explaining the conclusion of his own model, the author of the report did not analyze the possible defects of the model he used. It was irresponsible to attribute the factors which could not be explained to the "artificial adjustment".

At the same time, the article also questioned the formula used by the authors of the price index, and thought that it would be understandable to use the incomplete data to evaluate the CPI data. As a scientific research work, it is not rigorous enough to make no necessary explanation for the limitation of the research conclusion and to release it externally.

Pang Xiaolin said that "authentic and credible" is the sincere request of all sectors of the society for statistical work, and it is also the professional ethics that statisticians must abide by. All sectors of society are very concerned about CPI, and it is our motivation to do this work well. As always, we sincerely welcome all sectors of the community to offer reasonable improvements and suggestions for price statistics.

　 Appendix: Statistics Bureau website "Pang Xiaolin: CPI is not calculated by model".

In November 9th, some media and websites published the article titled "the CPI of the Academy of social sciences has been artificially adjusted to be underestimated 7% in 5 years". It is believed that it is derived from the analysis report of Xu Qiyuan, a researcher at the Academy of Social Sciences, "data and subjective feelings: CPI is wind or sail". We carefully studied the contents of the report and Mr. Xu's article, and concluded that the conclusion of the media report is subjective inference, which is inconsistent with the facts. The media did not verify the reliability of the report, and the headlines were misleading the public. {page_break}

First, the mathematical model is only an analytical tool, and it is not suitable for direct production of statistical data. The conclusion of "underestimation of 7%" through mathematical models is just a saying, not the consensus of mainstream experts and scholars. Moreover, most experts and scholars are very cautious about using mathematical models to draw conclusions. They are mostly used as reference data and will not be used as the basis for judging facts. At present, the price index compiled and released by the statistical department has strict compilation procedures and scientific system methods. It is in line with international practice. The original data is collected directly by people at fixed time, and it is authentic and credible. It can reflect market price changes and their trend of change. Without explaining the conclusion of his own model, the author of the report did not analyze the possible defects of the model he used. It was irresponsible to attribute the factors which could not be explained to the "artificial adjustment".

Two, there are many formulas for calculating the price index, both Laplace's formula and pie's formula and ideal formula. For all the advantages and disadvantages of the above calculation formulas, statisticians all over the world share a common understanding that using the Lagrange formula to calculate the price index tends to overestimate, and the pie formula is closer to the actual situation. Based on the same basic data, the results calculated by using two different formulas must be different. Because of the cost of investigation and the limitations of basic data sources, most countries in the world use the Lagrange formula to calculate the price index and adjust the "commodity basket" every five years. China's price index is also adjusted once every five years as a "commodity basket". According to the survey data and relevant information of 120 thousand households in urban and rural areas, the weights are adjusted annually. This is because with the rapid development of China's economy and the continuous improvement of the living standard of urban and rural residents, the consumption structure is also changing. In addition, we have detailed and informative household consumption expenditure survey data every year. Therefore, it is necessary to adjust the CPI weights every year, and it is also in line with the actual situation of our country. The author uses pure Lagrange formula and uses incomplete data to evaluate CPI data. As a scientific research work, of course, it is understandable, but it is not rigorous enough to make no necessary explanation for the limitations of the research conclusion and to release it externally.

"Authentic and trustworthy" is the sincere request of all sectors of the society for statistical work, and it is also the professional ethics that statisticians must abide by. All sectors of society are very concerned about CPI, and it is our motivation to do this work well. As always, we sincerely welcome all sectors of the community to offer reasonable improvements and suggestions for price statistics.