The behaviour of the US consumer price index 1913-2003: a study of seasonality in the monthly US CPI
Abstract:This article analyses the seasonality in the monthly consumer price index (CPI) over the period January 1913 to December 2003. We examine three types of month effects: if the mean of monthly CPI changes of the entire data set, and of a given month were significantly different from zero; if the mean of monthly CPI changes of a given month was different from the mean of the other months; and if the variance of the monthly CPI changes for a given month was different from the variance of the other months. The mean of monthly CPI changes for the entire data set (0.27%) was found to be significantly greater than zero. The means of monthly changes show a downward trend from September to December. When the data are sliced into three sub-periods, we find an increasing trend in the means and medians of monthly changes but a decreasing trend in the SDs of the monthly changes. The mean of monthly CPI changes during the republican presidencies (0.15%) was significantly lower than during the democratic presidencies (0.38%).
Document Type: Research Article
Affiliations: School of Business, Southern New Hampshire University, Manchester, NH 03106-1045, USA
Publication date: July 1, 2008