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### 国际比较项目中的中国PPP偏差问题

• 出版日期:2018-09-25 发布日期:2018-09-25

### Deviation of China’s PPP in the International Comparison Program

Xiang Shujian & Li Kai

• Online:2018-09-25 Published:2018-09-25

Abstract: There was a deviation of the measurement results from the report of 2011 World International Comparison Program (ICP) published in 20014 by the World Bank in comparison with the real economic scale of the developing economies. It triggered doubts on whether the purchasing power parity (PPP) was systematically underestimated in the developing economies. Therefore, based on the measurements of the ICP of China and the expenditure method of the global ICP, an analysis was undertaken on the issues of deviation of China’s PPP. The results show in theory, the data on GDP expenditure and the price data for standard items that are required by ICP provided by the participating countries are influenced by the segmentation of the markets within a large country. It is a prerequisite to identify the degree of segmentation of the markets, i.e., spatial association, for ICP surveys. The empirical results based on the spatial econometric models further show that: (i) In the seventh and eighth rounds of the ICP surveys, the segmentation of China’s internal markets led to the existence of spatial and temporal differences in price levels, that largely reduced the accuracy of PPP calculation in China; (ii) The market segmentation resulted in the randomness of the price discrepancy in various regions of China in the short term, and only possible to have convergence in the long term. However, the frequency of ICP survey in 2017 was reduced from 6 years to 3 years in 2017, making this convergence hard to occur in the ICP survey period; (iii) ICP 2017 adopted the rolling reference period to calculate PPP, but this change cannot spatially cover the differing forcing effects of the expenditure items in China’s segmented markets. So it would not be possible to reduce the bias in the calculation by even using the PPP estimation. Only based on different weights attributed to where the items comes from can we improve the accuracy of PPP estimation