Disinflation and the NAIRU in a New-Keynesian New-Growth Model (Extended Version)

Unemployment in the big continental European economies like France and Germany has been substantially increasing since the mid 1970s. So far it has been difficult to empirically explain the increase in unemployment in these countries via changes in supposedly employment unfriendly institutions like the generosity and duration of unemployment benefits. At the same time, there is some evidence produced by Ball (1996, 1999) saying that tight monetary policy during the disinflations of the 1980s caused a subsequent increase in the NAIRU, and that there is a relationship between the increase in the NAIRU and the size of the disinflation during that period across advanced OECD economies. There is also mounting evidence suggesting a role of the slowdown in productivity growth, e.g. Nickell et al. (2005), IMF (2003), Blanchard and Wolfers (2000). This paper introduces endogenous growth via a capital stock externality into an otherwise standard New Keynesian model with capital accumulation and unemployment. We subject the model to a cost push shock lasting for 1 quarter, in order to mimic a scenario akin to the one faced by central banks at the end of the 1970s. Monetary policy implements a disinflation by following a standard interest feedback rule calibrated to an estimate of a Bundesbank reaction function. About 40 quarters after the shock has vanished, unemployment is still about 1.7 percentage points above its steady state, while annual productivity growth has decreased. Over the same horizon, a higher weight on the output gap increases employment (i.e. reduces the fall in employment below its steady state). Thus the model generates an increase in unemployment following a disinflation without relying on a change to labour market structure. We are also able to coarsely reproduce cross country differences in unemployment. A higher disinflation generated by a larger cost push shock causes a stronger persistent increase in unemployment, the correlation noted by Ball. For a given cost push shock, a policy rule estimated by Clarida, Gali and Gertler (1998) for the Bundesbank and the Federal Reserve Bank produces a stronger persistent increase in the case of the Bundesbank than of the Federal Reserve. Testable differences in real wage rigidity between continental Europe and the United States, namely, as pointed out by Blanchard and Katz (1999), the presence of the labour share in the wage setting function for Europe with a negative coefficient but it's absence in the U.S. also imply different unemployment outcomes following a cost push shock. If real wage growth does not depend on the labour share, the persistent increase in unemployment is about one percentage point smaller than when it does. To the extent that the wage setting structure is determined by labour market rigidities, "Shocks and Institutions" jointly determine the unemployment outcome, as suggested by Blanchard and Wolfers (2000). The calibration of unobservable model parameters is guided by a comparison of second moments of key variables of the model with Western German data. The endogenous growth model matches the moments better than a model without endogenous growth but otherwise identical features. This is particularly true for the persistence in employment as measured by first and higher order autocorrelation coefficients