When Ben Bernanke was a professor at Princeton University—he's still actually a professor—he wrote a series of important articles on what he referred to as the global savings glut. In other words, this means there is an excess of savings in the world and not enough investment projects. That is why we have seen a downward trend in long-term interest rates. A number of factors are involved, but population aging in a number of countries is one of the factors that stand out. This leads to a savings glut compared with demand in investment. When there are more savings and less investment, interest rates are lower.
The reason why that affects monetary policy is the implication that we will probably reach the effective lower bound of our key interest rate more often. That suggests that we will need, as is the case now, to use other tools, such as quantitative easing, to strengthen our forward guidance in relation to our key interest rate.
So I do think that is an important study.