سیاست های پولی فرصت طلب: جایگزینی اصول عقلانی

This paper offers an alternative rationalization for opportunistic behaviour, i.e., a gradual disinflation strategy where policymakers react asymmetrically to supply shocks, opting to disinflate only in recessionary period. Specifically, we show that adaptive expectations combined with asymmetry in the Phillips curve of a specific sort together provide an optimizing justification for opportunism. However, the empirical basis for these conditions to be satisfied in the current low-inflation context of most OECD countries remains however to be established.

During the 1990s many central banks pursued monetary policies committed to keeping inflation at or close to a target, with a secondary objective of stabilising output. Under rational expectations with a standard Phillips curve, such policies can be shown to be optimal. This principle has been challenged in the 1990s, somewhat surprisingly, by senior policymakers at the Fed, who have argued for ‘opportunism’ in monetary policy and have opposed the setting of a single central inflation target.1 Their argument is that the Fed should move towards its long-run ambitions for inflation gradually and exploit opportunities for inflation reductions as they occur, for example through favourable supply shocks. The ‘opportunistic’ approach to monetary policy can be neatly divided into two halves. First and foremost, there is the idea of delay: one should not pursue a target for inflation that is too ambitious in the short run-it is ‘impractical’. Rather one should pursue a practical target for inflation that is within grasp in the short term-an interim target. Secondly, there is the idea of asymmetry: one acts to reduce inflation when the economy is already producing lower inflation via a favourable burst of circumstances (a ‘good supply shock’).2 One does not try to reduce inflation when inflation is strengthening; rather one aims to dampen it then-to ‘hold the fort’ as it were.3 For the process of disinflation from high (double digit) initial levels of inflation such ideas have been widely defended. However, in the conditions of the 1990s when inflation was already well within single digits, they seem rather surprising. Yet in the not so distant past, the late 1990s, there has been a recrudescence of these ideas in Federal Reserve pronouncements (see Meyer (1996) and Blinder (1997)). These ideas do seem incongruous in the light of optimising agents using information efficiently and a social objective function derived from these agents’ utility. Nevertheless, it is only right to examine such claims carefully when they emanate from the world's most powerful central bank. This paper offers an alternative rationalization for opportunistic behaviour-alternative, that is, to the one given by Orphanides and Wilcox (2002).4 Specifically, we show that adaptive expectations combined with asymmetry in the Phillips curve of a specific sort (i.e., a nonlinear effect of the shock on the position of the Phillips curve trade-off) together provide an optimizing justification for opportunism. Here adaptive inflation expectations provides the justification for delay in asserting the ultimate inflation target, i.e., it acts as a proxy for market participants’ learning in a context of uncertainty regarding policymakers’ tastes and objectives. Nevertheless, the empirical basis for these conditions in the current low-inflation context of most OECD countries remains to be established. To anticipate our main conclusions, we find that rigorous defence of the opportunitic strategy can be mounted even if its empirical foundations may not obviously be robust. In Section 2 we derive an optimal inflation response when the policymaker is opportunistic. The implications of opportunism are also explored. Section 3 seeks a set of sufficient conditions under which the opportunistic strategy is optimal for a central bank maximising the preferences of the representative agent. 5 Section 4 provides concluding remarks.

This paper offers an alternative rationalization for opportunistic behaviour, i.e., a gradual disinflation strategy where policymakers react asymmetrically to supply shocks, opting to disinflate only in recessionary period. Under rational expectations with a standard (linear) Phillips curve, such policies can be shown to be suboptimal (see Minford & Srinivasan, 2003). Thus, opportunism poses a theoretical puzzle, which this paper attempts to resolve by finding a set of sufficient conditions under which it is optimal. We showed that adaptive expectations combined with asymmetry in the Phillips curve of a specific sort (i.e., a nonlinear effect of the shock on the position of the Phillips curve trade-off) together provide an optimising justification for opportunism. Although the set of conditions examined are theoretically feasible the empirical basis for these in the current low-inflation context of most OECD countries remains however to be established.