After short-term interest rates in many advanced economies fell below 1 percent, central banks turned to quantitative easing (QE) to support economic growth.
They purchased massive and unprecedented amounts of long-term bonds in an effort to reduce long-term borrowing costs. Nevertheless, recovery from the Great Recession proved disappointingly slow. Recently, some central banks have pushed short-term interest rates slightly below zero to provide an additional boost to growth. The slow recovery and the turn to negative rates have raised questions about the benefits of QE bond purchases and whether their effectiveness has reached a limit. Gagnon reviews the outpouring of research on QE and its effects and finds overwhelming evidence that QE does ease financial conditions and supports economic growth. The channels are similar to those of conventional monetary policy. QE can be especially powerful during times of financial stress, but it has a significant effect in normal times with no observed diminishing returns. Rarely, if ever, have economists studying a specific question reached such a widely held consensus so quickly. But this consensus has yet to spread more broadly within the economics profession or the wider world.