Published Quarterly Journal of Economics Online 13 Aug 2025 Published Oct 2025Aggregation and the Estimation of Quality Change: Application to U.S. Import PricesMarco Errico · Danial LashkariErrico and Lashkari address two intertwined problems in the measurement of aggregate price indices: how to account for quality change and variety entry/exit when the demand system is not CES, and how …