What Makes the Output–Inflation Trade‐Off Change? The Absence of Accelerating Deflation in Japan
检验日本1990年代末大负产出缺口未引发加速通缩的现象，发现菲利普斯曲线逐渐平坦化，并认为内生价格持续期模型最能解释这一变化，提示趋势通胀变化时曲线斜率时变不可忽视。
It is standard to model the output–inflation trade‐off as a linear relationship with a time‐invariant slope. We assess empirical evidence for two sets of theories that allow for endogenous variation in the slope of the short‐run Phillips curve. At an empirical level, we examine why large negative output gaps in Japan in the late 1990s did not lead to accelerating deflation but instead coincided with stable, albeit moderately negative inflation. Our results suggest that this episode is most convincingly interpreted as reflecting a gradual flattening of the Phillips curve. We find that this flattening is best explained by models with endogenous price durations. These models imply 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 Phillips curve has become too important to ignore.