Instability in U.S. inflation: 1967-2005

Maintaining stables prices and keeping inflation in check have become key policy objectives of the Federal Reserve and other central banks. Evidence indicates that inflation has become less persistent and volatile since the early 1980s. Although economists have examined the implications for inflation modeling and forecasting, little information exists about whether changes or instabilities in inflation dynamics coincide with specific economic events such as oil price shocks or recessions. ; This article studies U.S. monthly inflation, inflation growth, and price level dynamics from January 1967 to September 2005. The author employs four price level measures?two versions of the monthly consumer price index and two versions of the monthly personal consumption expenditure deflator?with the goal of identifying possible instabilities in these dynamics. ; Autoregressive, moving average, and unobserved components models provide estimates on various aspects of inflation and price levels. Two rolling samples spanning the 1967?2005 period are constructed to uncover evidence about possible instability in mean inflation and the persistence and volatility of inflation and inflation growth. ; One way to summarize the empirical results is that this instability coincides with different economic events such as the oil price shocks of the 1970s or the end of the 1990?91 recession. An unresolved question is whether such changes are one-time events or can be expected to be repeated systematically in the future.