购买力平价汇总方法测算稳定性研究

Research on the Measurement Stability of Purchasing Power Parity Aggregation Methods

汇总方法和基础数据是购买力平价(PPP)测度的两大核心,就PPP测算结果的质量而言,比汇总方法理论性质更为重要的是其与基础数据质量的匹配程度。从PPP测度实践来看,全球范围内参与国际比较项目(ICP)经济体的基础数据质量呈“偏态分布”是难以避免的客观现实,其对PPP测算结果的影响已有一定定性认识,但对于具体影响的形式和程度,还缺乏必要的量化研究。本文以汇总方法的稳定性为切入点,通过对基础数据质量因素的量化模拟,探讨PPP汇总方法的测算特性,一方面能够补充对汇总方法的理论认识,另一方面能够为优化PPP测度实践提供借鉴。具体包括以下内容:一是基于稳定性的一般定义和PPP测度实践,阐述和讨论PPP汇总方法测算稳定性的内涵和意义;二是从内生数据干扰角度,模拟测度和分析GEKS法的测算稳定性特征;三是从外生数据干扰角度,模拟测度和比较分析GEKS法、GK法及其衍生方法的测算稳定性;四是综合前述测度和分析结果得出对ICP实践具有借鉴价值的结论与启示。

Aggregation method and basic data are the two cores of purchasing power parity(PPP)measurement.In terms of the quality of PPP measurement results,compared to the theoretical nature of aggregation method,the matching degree between aggregation method and the quality of basic data is more important.In PPP measurement practice,the inescapable reality is that the basic data quality of global economies participating in international comparison program(ICP) has the feature of “skewness distribution”.The influence of this reality on PPP measurement is showed in some qualitative research,but the form and extent of the influence still lack the necessary qualitative research to provide support.In this paper,the stability of aggregation methods is taken as the entry point and the measurement characteristics of PPP aggregation methods are deeply discussed through the quantitative simulation of basic data quality factors.On the one hand,this paper could supplement the theoretical understanding of aggregation methods and on the other hand it could provide reference for optimizing the practice of PPP measurement.This paper contains the following four parts.First,based on the general definition of stability and PPP measurement practice,the connotation and significance of measurement stability of PPP aggregation method are expounded and discussed.Second,from the perspective of endogenous data interference,the measurement stability characteristics of GEKS method are measured by simulation method.Third,from the perspective of exogenous data interference,the measurement stability of GEKS,GK and their derived methods are simulatively measured and comparatively analyzed.Finally,some conclusions and enlightenments for ICP practice are summarized according to the above measurement and analysis results.