شوک های اقتصاد کلان، بازار کار متحد شده و سیاست فاش سازی بانک مرکزی : چگونه افزایش شفافیت مفید است؟

The paper investigates the implications of disclosure by the central bank to the private sector of information relating to the current realizations of macroeconomic disturbances. In the context of an economy in which the goods market is monopolistically competitive and where wages are set by atomistic unions, we find that greater precision of information provided to wage setters in respect of supply shocks has ambiguous welfare effects, both from the perspective of the social loss function and from the viewpoint of unions who act on the information. An important feature of the model is an externality in union wage setting which implies the outcome of the wage determination process is collectively inefficient.

One of the most significant trends in the conduct of monetary policy over recent years has been the move towards greater transparency by the world's central banks. It is now the norm to find information relating to central bank objectives, operating procedures and decision-making processes all placed within the public domain. In part, this drive towards increased transparency can be explained in terms of the parallel shift to greater central bank independence and the need, in this context, to ensure continued accountability of monetary policy institutions to government and the wider public. Additionally, though, fuller disclosure of central bank goals and the factors underlying its policy decisions, in particular its assessment of the current and likely future state of the economy, is argued by many to enhance the efficacy of monetary policy and, hence, to aid the central bank in pursuit of its objectives: see Blinder et al. (2001) for a clear statement of this view. Although this latter motivation for openness in policymaking may hold an immediate appeal, existing theoretical models appear to provide a less than unequivocal endorsement of its general validity. The ambiguous welfare effects of increased transparency are a key finding of Cukierman and Meltzer's (1986) influential study1, and this theme is present in a range of papers which examine different dimensions of the issue: see, for example: Eijffinger et al., 2000 and Grüner, 2002 and Jensen (2002). A review of the relevant literature and a clear analysis of the conflicting forces which may arise as a consequence of greater transparency in monetary policy are presented in Geraats' (2002) comprehensive overview.2 More recent contributions to the transparency literature are considered in the surveys of Cruijsen and Eijffinger (2007) and Blinder et al. (2008). While the literature on central bank transparency has considered the issue from a variety of perspectives, a feature which is common to much of it is the central role played by the stabilization function of monetary policy, with the realized values of exogenous shocks, or alternatively their forecast values, assumed to be private information of the central bank. The latter assumption, a standard feature of much monetary policy analysis, raises the question of the extent to which it is desirable for the central bank to disclose its information regarding shocks to the private sector. This issue relates to the desirability of economic 3 transparency, as defined by Geraats (2002), and lies at the centre of a number of contributions. Several of these explore the relationship between transparency concerning shocks and central bank credibility using models which assume some uncertainty on the part of the private sector regarding central bank objectives. Jensen (2000) and Eijffinger and Tesfaselassie (2007), for example, investigate the welfare consequences of disclosure by the central bank of its information regarding cost-push shocks, when firms' pricing decisions depend upon their expectations of future (rather than current-period) inflation, and the economy is consequently characterized by a New Keynesian Phillips curve. 4 Jensen finds disclosure of current-period shocks induces an adjustment in expectations of future inflation which compromises the central bank's ability to stabilize the shocks' current impact, and therefore lowers welfare if the central bank's credibility is sufficiently high (and the mean inflation bias correspondingly low). Eijffinger and Tesfaselassie, focusing instead on disclosures of future shocks, confirm that in general Jensen's anti-transparency conclusions also apply to scenarios in which the central bank is known not to have an output-related temptation to create inflation (i.e. enjoys high credibility). 5 Reflecting the different economic structure assumed, Geraats' (2005) study, in contrast, finds a result which is more favourable to economic transparency: in her model disclosures of central bank forecasts of shocks may enhance welfare by allowing the interest rate to signal more clearly a resolve on the part of the central bank to fight inflation. Unlike the three aforementioned works, the papers by Cukierman (2001) and Gersbach (2003) abstract from reputational considerations by assuming the private sector to have complete knowledge of central bank objectives, and focus on the direct consequences of disclosure for private sector expectations and the resulting output and employment outcomes. The common approach adopted in these two contributions leads to an identical and unequivocal result. Specifically, they find that increased transparency in respect of supply shocks is associated with greater instability in output and employment and consequently, given the standard specification of the social loss function employed, has an unambiguously detrimental effect on welfare. Because the present paper shares a common focus with the contributions of Cukierman and Gersbach, it is useful to identify the economic logic which underlies their finding. Both studies assume aggregate employment, l, to be determined by a relationship of the form: l = a(π − πe) + θ, where π and πe are, respectively, actual and expected inflation, while θ represents a random supply shock. In this context, so long as θ remains the private information of the central bank, the latter can adjust actual inflation relative to expected inflation in such a fashion as to offset the impact of the shock on employment. However, if the value of θ is disclosed to the public, knowledge of central bank objectives allows the policy response of the central bank to be fully anticipated. Consequently actual inflation will not diverge from its expected value, and non-zero realizations of θ are reflected fully in movements in employment. A potential limitation of the foregoing argument derives from the augmented Phillips curve relationship which underlies it. In particular, the latter's specification precludes any private sector response to anticipated supply shocks other than that working indirectly through inflation expectations. This implication of the employment-determination equation appears unduly restrictive, and it is certainly possible to conceive of structural underpinnings for the relationship which imply a direct private sector reaction (i.e. additional to that associated with expected inflation) to anticipated shocks. The present paper develops this argument using a model of an economy in which wages are set by atomistic unions and where the product market is modelled as monopolistically competitive, though capturing perfect competition as a limiting case. Whilst a substantial body of work examining the interaction between monetary policy and union wage setting has evolved over recent years,6 as Geraats (2002) indicates this literature has to date paid little attention to the particular issue of central bank transparency. Within the framework, the realized values of the supply shocks to which the economy is subject are the private information of the central bank, to which it can respond in terms of its setting of monetary policy. However, prior to the setting of wages, the central bank can supply a potentially noisy signal of the shock's value to unions. In this context, we associate transparency with the degree of accuracy of the signal: our interest then lies in the relationship between signal precision and welfare outcomes, as reflected in the expected values of the union and social losses. A key aspect of the analysis is the specification of union objectives, which relate to both employment and the real wage. Given its expectation of the supply shock, conditional on the signal provided by the central bank, each union will set its nominal wage with the aim of attaining the optimal trade-off between employment and real wage stability. Thus, the aggregate nominal wage response to any signal of a non-zero realization of the shock will depend on the weight attached by unions to employment relative to the real wage. The interaction between union wage setting and monetary policy then determines aggregate employment and the price level. While our framework is shown to capture the results of Cukierman (2001) and Gersbach (2003) as a limiting case, we find that, in general, the welfare effects of greater transparency are ambiguous in direction, and depend crucially on the relative emphasis placed by unions on employment stability compared to society, with other key characteristics of economic structure also playing an important role. Of particular significance for our results is an externality present in union wage setting, which leads to an inefficient aggregate wage response to the central bank's signal. This feature gives rise to a further noteworthy aspect of our findings: that is, the possibility that an improvement in signal quality may be detrimental to unions as well as society, with this outcome more likely the closer are the relative weights attached to employment stability in the union and social loss functions. The remainder of the paper is organized as follows. Section 2 provides an outline of the model, with the characteristics of the equilibrium identified in Section 3. Section 4 presents and discusses our principal results, relating to the welfare implications of the quality of information provided by the central bank to the private sector. Finally, Section 5 concludes.

The macroeconomic implications of increased central bank transparency provide the focus for an important and growing strand of literature, with the issue explored from a number of alternative angles and in the context of a variety of different models. The analysis of the present paper has centred on the consequences of greater transparency in relation to supply shocks and the resulting interaction between monetary policy and the uncoordinated wage decisions of atomistic unions. In providing a detailed analysis of the implications of goods and labour market structure and the objectives of wage setters, the paper arrives at somewhat less negative conclusions with regard to the desirability of increased transparency than do the related contributions of Cukierman (2001) and Gersbach (2003). Nonetheless its findings offer far from unequivocal support for the view that greater transparency is likely to be beneficial: in this regard its conclusions echo those of the wider literature. However, the paper also provides a more distinctive contribution in drawing attention to a number of factors, abstracted from in previous work, but which are likely to be significant for the desirability, or otherwise, of increased transparency in monetary policy. Moreover, since the economic characteristics identified as relevant to this issue, in particular the relative importance attached to employment stability by unions and by society, the degree of product market competition and the economy's wage bargaining structure, differ significantly across economies, our results suggest that a universally valid prescription in respect of central bank disclosure policy is unlikely to be found.