Effectiveness of unconventional monetary policies in a low interest rate environment

Have unconventional monetary policies (UMPs) become less effective at stimulating economies in persistently low interest rate environments? This paper examines that question with a time-varying parameter VAR for the United States, the United Kingdom, the euro area and Japan. One advantage of our approach is the ability to measure an economy's evolving interest rate sensitivity during the post-GFC macroeconomy. Another advantage is the ability to capture time variation in the "natural", or steady state, rate of interest, which allows us to separate interest rate movements that are associated with changes in the stance of monetary policy from those that are not.