Understanding Persistent ZLB: Theory and Assessment

Concerns of prolonged stagnation periods with near-zero interest rates and deflation have become widespread in many advanced economies. We build a theoretical framework that rationalizes two theories of low interest rates: expectations-trap and secular stagnation in a unified setting. We analytically derive contrasting policy implications under each hypothesis and identify robust policies that eliminate expectations-trap and reduce the severity of secular stagnation episodes. We provide a quantitative assessment of the Japanese experience from 1998:Q1-2020:Q4. We find evidence favoring the expectations-trap hypothesis and show that equilibrium indeterminacy is essential to distinguish between theories of low interest rates in the data.