Can Chained Price Deflators for High‐Tech Goods Overstate Quality Change?
研究指出链式价格指数在信息技术产品中可能无法正确核算质量变化，即“混杂”问题，并通过五种电子产品的扫描数据比较链式Törnqvist指数与加权时间产品虚拟指数，发现前者下降更快。
ABSTRACT This paper argues that chained price indexes for IT goods will typically not account for quality change properly, a problem we call commingling. We illustrate the problem by comparing a chained index to the weighted time product dummy index, where we argue that the latter does not commingle. A comparison of these indexes suggests that the patterns typically seen in prices and expenditure shares over these goods' lifecycles can push the chained Törnqvist index to fall faster than the WTPD index. Our empirical work uses scanner data for five electronic goods and shows that (1) goods in four of our categories display the emblematic patterns (calculators were the exception) and (2) three of those display chained Tornquist indexes that fall substantially faster than the WTPD index (tablets were the exception).