It is currently popular to identify monetary policy shocks with innovations in some measure of reserves or in the federal funds rate. These assumptions about the interest elasticity of the supply of or demand for reserves imply monetary policy shocks that produce dynamic responses of macroeconomic variables that are anomalous relative to traditional monetary analyses. This paper tentatively identifies supply and demand shocks in the markets for reserves and M2 for the 1980s and contrasts them with results for the 1970s. In the later period, identified monetary policy shocks have dynamic impacts that are fully consistent with traditional analyses.

A discretionary policymaker can create surprise inflation, which may reduce employment and raise government revenue. But when people understand the policymaker's objectives, these surprises cannot occur systematically. In equilibrium people form expectations rationally and the policymaker optimizes in each period, subject to the way that people form expectations. Then, we find that (1) the rates of monetary growth and inflation are excessive; (2) these rates depend on the slope of Phillips curve, the natural unemployment rate, and other variables that affect the benefits and costs from inflation; (3) the monetary authority behaves countercyclically; and (4) unemployment is independent of money policy. Outcomes improve if rules commit future policy choices in the appropriate manner. The value of these commitments--which amount to long-term contracts between the government and the private sector--underlies the argument for rules over discretion.

It is currently popular to identify monetary policy shocks with innovations in some measure of reserves or in the federal funds rate. These assumptions about the interest elasticity of the supply of or demand for reserves imply monetary policy shocks that produce dynamic responses of macroeconomic variables that are anomalous relative to traditional monetary analyses. This paper tentatively identifies supply and demand shocks in the markets for reserves and M2 for the 1980s and contrasts them with results for the 1970s. In the later period, identified monetary policy shocks have dynamic impacts that are fully consistent with traditional analyses.

Natural-rate models suggest that the systematic parts of monetary policy will not have important consequences for the business cycle. Nevertheless, we often observe high and variable rates of monetary growth, and a tendency for monetary authorities to pursue countercyclical policies. This behavior is shown to be consistent with a rational expectations equilibrium in a discretionary environment where the policymaker pursues a "reasonable" objective, but where precommitments on monetary growth are precluded. At each point in time, the policymaker optimizes subject to given inflationary expectations, which determine a Phillips Curve-type tradeoff between monetary growth/inflation and unemployment. Inflationary expectations are formed with the knowledge that policymakers will be in this situation. Accordingly, equilibrium excludes systematic deviations between actual and expected inflation, which means that the equilibrium unemployment rate ends up independent of "policy" in our model. However, the equilibrium rates of monetary growth/inflation depend on various parameters, including the slope of the Phillips Curve, the costs attached to unemployment versus inflation, and the level of the natural unemployment rate. The monetary authority determines an average inflation rate that is "excessive, " and also tends to behave countercyclically. Outcomes are shown to improve if a costlessly operating rule is implemented in order to precomrnit future policy choices in the appropriate manner. The value of these precommitments -- that is, of long-term agreements between the government and the private sector -- underlies the argument for rules over discretion. Discretion is the sub-set of rules that provides no guarantees about the government's future behavior.