Measured productivity is strongly procyclical. Real business cycle theories suggest that actual fluctuations in productivity are the source of fluctuations in aggregate output. Keynesian theories maintain that fluctuations in aggregate output come from shocks to aggregate demand. Keynesian...

Supply shocks played an important role in macroeconomic fluctuations during the 1970's. Supply shocks are also increasingly important in Keynesian and neo-classical models of the business cycle. This paper is a short survey of these theoretical models. It also discusses the history of supply...

This paper explores the theoretical foundations of a new approach to monetary policy. Proponents of this approach hold that when inflation is moderate but still above the long-run objective, the Fed should not take deliberate anti- inflation action, but rather should wait for external...

Under a conventional policy rule, a central bank adjusts its policy rate linearly according to the gap between inflation and its target, and the gap between output and its potential. Under the opportunistic approach to disinflation a central bank controls inflation aggressively when inflation is...

A number of observers have advocated recently that the Federal Reserve take an "opportunistic" approach to the conduct of monetary policy. A hallmark of this approach is that the central bank focuses on fighting inflation when inflation is high but focuses on stabilizing output when inflation is...