This paper proposes a tractable New Keynesian (NK) economy with endogenous adjustment in product quality that nests the canonical framework. Endogenous quality choice reduces the slope of the traditional NK Phillips curve and ampliffes the economy's response to productivity shocks. This leads to...

The interaction of macroeconomic variables may change as the nominal shortterm interest rates approaches zero. In this paper, we propose an empirical model capturing these changing dynamics with a time-varying parameter vector autoregressive process. State-dependent parameters are determined by...