This paper analyzes a regime-switching New Keynesian model to understand what happens to the aggregate economy when the nominal interest rate hits the zero lower bound (ZLB). Contrary to the literature, our model predicts that the aggregate demand curve is not always upward sloping when the ZLB binds. Instead, it depends on expectations. If the expected duration of the ZLB is short but consistent with expectations surveys, the AD curve can be downward sloping. In that case, the fiscal multiplier is moderate and supply-side reforms are expansionary. These results complement existing findings in the literature.

中文翻译：

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关于零下限总需求曲线斜率的注释

本文分析了一种制度转换的新凯恩斯模型，以了解当名义利率达到零下限 (ZLB) 时总体经济会发生什么。与文献相反，我们的模型预测，当 ZLB 绑定时，总需求曲线并不总是向上倾斜。相反，它取决于期望。如果 ZLB 的预期持续时间较短但与预期调查一致，则 AD 曲线可能向下倾斜。在这种情况下，财政乘数是适度的，供给侧改革是扩张性的。这些结果补充了文献中的现有发现。