Whose inflation? A characterization of the CPI plutocratic gap
分解了标准CPI与民主加权指数之间的差异（即CPI富豪差距），将其表示为支出不平等与个体价格指数和支出弹性参数的协方差之积，有助于理解该差距的大小和符号变化。
Abstract. Prais (1958) showed that the standard CPI computed by most statistical agencies can be interpreted as a weighted average of household price indexes, where the weight of each household is determined by its total expenditures. In this paper, we decompose the difference between the standard CPI and a democratically weighted index (i.e., the CPI plutocratic gap) as the product of expenditure inequality and the sample covariance between the elementary individual price indexes and a parameter which is a function of the expenditure elasticity of each good. This decomposition allows us to interpret variations in the size and sign of the plutocratic gap, and also to discuss issues pertaining to group indexes.