The consumer price index

The consumer price index (CPI) is probably the most closely watched indicator of inflation in the U.S. economy. In this article, Mark Wynne and Fiona Sigalla explain the construction of the CPI and evaluate some of its potential shortcomings as a measure of inflation. Specifically, they examine the discrepancies that arise between the CPI and the true cost- of-living index as a result of improvements in the quality of goods, the introduction of new goods, substitution on the part of consumers between different goods and retail outlets, and the difficulty of measuring the prices actually paid by consumers for the goods they purchase. ; The authors review the literature that quantifies these discrepancies, with the objective of estimating the magnitude of the overall bias in the CPI. Wynne and Sigalla argue that, in fact, remarkably little is known about the extent or significance of the overall bias in the CPI. They conclude that biases in the CPI cause it to overstate inflation by no more than 1 percent a year, and probably less.