关键词: 价格异方差, CPD法, PPPs, WLS估计

Abstract:

The CPD method is an important method of multilateral price comparisons in the International Comparison Program（ICP）, and the method of multilateral price comparisons will directly influence the reliability of each country’s purchasing power parities data published by ICP. This paper in theory analyses the price heteroscedasticity in CPD method, and introduces a WLS estimation method to eliminate heteroscedasticity. Then, using the price data of the real consumption expenditure by households in 2011 ICP, it empirically proves that the CPD method under the WLS estimation can improve the reliability of each country’s purchasing power parities data; relatively, the CPD method with heteroscedasticity will systematically overvalue the real consumption expenditure in developing countries.

Key words: Price Heteroscedasticity ;CPD Method ;PPPs, WLS Estimation