Among the commodities and services covered by the Consumer Price Index (CPI), some may have prices affected by seasonal factors. In other words, the prices of these consumer items are, on a regular basis, relatively high in certain months of a year but relatively low in some other months. Through the application of statistical methods, clear and stable seasonal variations can be removed from the original series of the CPI so that the underlying price trend can be revealed more distinctly.
This article aims to introduce the features and the compilation method of the seasonally adjusted CPI and explore its applications. It also provides an analysis on the movements of the data concerned in recent years.