Factors that increase uncertainty—such as 5/7  BIS central bankers' speeches  geopolitical risks—can widen this zone temporarily. Conversely, resolution of uncertainties can narrow it. This is the essence of the Bank’s risk-management approach to monetary policy. Interpreting, weighing and managing those risks approaches art, but the art is built on the science of our models. Allow me to make three related points.
It is, at least in part, to counter that risk that central banks in a number of countries have kept interest rates very low and used unconventional monetary policies, such as quantitative easing, to provide additional stimulus to their economies. History has taught us that deflation usually comes in the wake of a financial crisis.