The Intermittent Phillips Curve: Finding a Stable (But Persistence- Dependent) Phillips Curve Model Specification

We make substantial progress on understanding the Phillips curve, yielding important monetarypolicy implications. Inflation responds differently to persistent versus moderately persistent (ortransient) fluctuations in the unemployment gap. This persistence-dependent relationship alignswith business-cycle stages, and is consistent with existing theory. Previous work fails to modelthis dependence, thereby finding the numerous “inflation puzzles” – e.g., missinginflation/disinflation – noted in the literature. Our specification eliminates these puzzles; e.g., thePhillips curve has not weakened; inflation’s post-2012 slow upward trudge was predictable. Themodel’s coefficients are stable, and it provides accurate out-of-sample conditional recursiveforecasts through the Great Recession and recovery.Keywords: overheating; recession gap; frequency dependence; NAIRU; Phillips curve.