Accession to the euro-area: a stylized analysis using a NK model


This paper analyses the accession to the euro-area by new members using a stylized new-Keynesian model. We analyze macroeconomic adjustment in the pre- and post-accession case and calculate welfare in both situations to obtain net benefit/loss from accession. It is shown how the effects of accession is related to the conduct of monetary policy and fiscal policy in the pre- and post-accession case. The simulation examples point at the potential costs that accession might entail due its consequences on monetary and fiscal policy design. These consequences from accession in terms of macroeconomic stabilization ability of monetary and fiscal policies have not always been fully acknowledged and may need more attention.

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  1. 1.

    Also for Bulgaria and Romania that will enter the EU on January 1, 2007 entering the EA will become a relevant aspect in the medium to long term.

  2. 2.

    In addition there are a number of additional effects that are ignored in this paper. These relate in particular to changes in the area of policy coordination in the EA and decision making inside the ECB. Accession changes the strategic settings and the possibilities for cooperation of policies for both acceding and existing member states. For the common central bank, the accession of additional countries, implies that: (1) there is a redefinition of the aggregate target variables; this by itself may already induce changes in optimal policymaking; (2) its preferences may change if the acceding countries have different preferences; this will affect policymaking; (3) the strategic configurations (coalition formation process) in which the common central bank operates have changed: the number of fiscal players in the monetary union increases and the number of outside monetary and fiscal players decreases. The adjustment dynamics from exchange rate adjustment are changed.

  3. 3.

    Output and output gap in fact can be used interchangeably as long as equilibrium output remains constant. Note that in a transition/accession context, it is very hard and arbitrary to determine such longer term equilibrium variables like potential output \(\overline y _t \) and equilibrium real interest rate \(\overline {r_t } \) since these will be subject still to changes over time, e.g. due structural breaks, an ongoing catching up process that introduces a clear deterministic trend in potential output and earlier a gradual disinflation process. In this paper we essentially ignore these aspects and limit ourselves by noting that these aspects are likely to further complicate the accession process and the determination of an optimal monetary and fiscal policy framework for the acceding countries. In that sense our results later on concerning the relative benefits from having national monetary and fiscal autonomy (the pre-accession phase) can be considered as a very conservative lower bound.

  4. 4.

    Net exports are a function of foreign output and price competitiveness: \({\text{net exports}} = \sigma y_t^{\operatorname{EA} } + \delta \left( {e_t + p_t^{\operatorname{EA} } - p_t } \right)\).

  5. 5.

    Leith and Malley (2002), Batini et al. (2003) and McCallum and Nelson (1999) provide micro-foundations for the presence of habit formation in consumption. Empirical evidence is provided that the backward looking component in consumption is substantial.

  6. 6.

    See e.g. Gagnon and Ihrig (2002), Leitemo et al. (2002), Coenen and Wieland (2002) that use similar open economy Phillips curves.

  7. 7.

    In technical terms the commitment solution follows the maximum principle or Hamiltonian approach of dynamic optimal control and the discretion solution the dynamic programming approach.

  8. 8.

    Discretionary policies will also induce an inflationary bias in case the policymaker chooses an output objective that exceeds the potential output, reflecting e.g. the case of a dependent Central Bank that is steered by political objectives. In the remainder of this study we will, however, not deal with such cases.

  9. 9.

    Note that in our analysis, we will assume that exchange rate expectations are always set in an entirely forward-looking manner.

  10. 10.

    See e.g. Dvorsky (2000) on CB independence in the countries in Central and Eastern Europe.

  11. 11.

    While the absence of any own empirical estimations may seem a bit unsatisfying this type of analysis based on calibrated parameters and/or parameters that appears plausible from empirical studies, is quite common in NK papers. See e.g. Jensen (2002) that follows this line of thought and analysis and refers to “compromise values” when choosing parameter values that would seem plausible for the US case in his analysis.

  12. 12.

    Another aspect that needs to mentioned is that even inside the group of accession countries there are likely to be asymmetries in terms of economic structures and macroeconomic shocks so that our approach here of modeling only one representative accession country (or the alternative interpretation that all the accession countries are lumped together here into one small accession country) implies severe implications when the results are applied to reality where the accession process is even more complex. Probably such heterogeneity in reality would further strengthen the case for a very cautious accession process.

  13. 13.

    Note that we ignore the benefits from accession in the form of lower transaction costs and other microeconomic efficiency gains, if these would amount to some amount Δ% we could subtract that amount from the OCA index to get the overall amount of net losses. Since we have no concrete estimate of Δ it is ignored in the analysis. Empirical studies suggest that these efficiency gains are typically in the range of 1–5% of GDP.

  14. 14.

    Note that these indices are dimensionless, they do not provide information concerning e.g. the costs/benefits of accession in terms of foregone/increased GDP as is sometimes tried in empirical studies.


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Correspondence to Bas van Aarle.

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van Aarle, B., Garretsen, H. & Moons, C. Accession to the euro-area: a stylized analysis using a NK model. Int Econ Econ Policy 5, 5–24 (2008).

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  • Euro-area
  • Fiscal policy
  • Monetary policy

JEL Classification

  • F31
  • F41
  • G15