This paper discusses the short-run tradeoff between inflation and unemployment. Although this tradeoff remains a necessary building block of business cycle theory, economists have yet to provide a completely satisfactory explanation for it. According to the consensus view among central bankers and monetary economists, a contractionary monetary shock raises unemployment, at least temporarily, and leads to a delayed and gradual fall in inflation. Standard dynamic models of price adjustment, however, cannot explain this pattern of responses. Reconciling the consensus view about the effects of monetary policy with models of price adjustment remains an outstanding puzzle for business cycle theorists.
Prepared as the Harry Johnson Lecture at the annual meeting of the Royal
Economic Society, July 2000.