Which nonlinearity in the Phillips curve? The absence of accelerating deflation in Japan

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Emmanuel De Veirman
Published as
De Veirman, Emmanuel (2009). ‘What makes the output-inflation trade-off change? The absence of accelerating deflation in Japan’, Journal of Money, Credit and Banking, Wiley, Volume 41(6), Pages 1117-1140, DOI: https://doi.org/10.1111/j.1538-4616.2009.00249.x.
It is standard to model the output-inflation trade-off as a linear relationship with a time-invariant slope. We assess empirical evidence for three types of nonlinearity in the short-run Phillips curve. At an empirical level, we aim to discover why large negative output gaps in Japan during the period 1998-2002 did not lead to accelerating deflation, but instead coincided with stable, albeit moderately negative, inflation. We document that this episode is most convincingly interpreted as reflecting a gradual flattening of the Phillips curve. Our analysis sheds light on the determinants of the time- variation in the Phillips curve slope. Our results suggest that, in any economy where trend inflation is substantially lower (or substantially higher) today than in past decades, time-variation in the slope of the short-run Phillips curve has become too important to ignore.