Consumption Subaggregates Should Not Be Used to Measure Poverty
从理论和实证上论证，使用消费子集（而非全面消费指标）来衡量贫困是不可靠的，因为其成立条件极为苛刻，且对卢旺达、坦桑尼亚和乌干达的数据分析表明实践中也不可行。
Abstract Frequent measurement of poverty is challenging because measurement often relies on complex and expensive expenditure surveys that try to measure expenditures on a comprehensive consumption aggregate. This paper investigates the use of consumption “subaggregates” instead. The use of consumption subaggregates is theoretically justified if and only if all Engel curves are linear for any realization of prices. This is very stringent. However, it may be possible to empirically identify certain goods that happen to have linear Engel curves given prevailing prices, and when the effect of price changes is small, such a subaggregate might work in practice. The paper constructs such linear subaggregates using data from Rwanda, Tanzania, and Uganda. The findings show that using subaggregates is ill advised in practice as well as in theory. This also raises questions about the consistency of the poverty tracking efforts currently applied across countries, since obtaining exhaustive consumption measures remains an unmet challenge.