The conclusion to "Leveraged bubbles," by Òscar Jordà, Moritz Schularick, and Alan Taylor:
... In this column, we turned to economic history for the first comprehensive assessment of the economic risks of asset price bubbles. We provide evidence about which types of bubbles matter and how their economic costs differ. Our historical analysis shows that not all bubbles are created equal. When credit growth fuels asset price bubbles, the dangers for the financial sector and the real economy are much more substantial. The damage done to the economy by the bursting of credit boom bubbles is significant and long lasting.
In the past decades, central banks typically have taken a hands-off approach to asset price bubbles and credit booms. This way of thinking has been criticised by some institutions, such as the BIS, that took a less rosy view of the self-equilibrating tendencies of financial markets and warned of the potentially grave consequences of leveraged asset price bubbles. The findings presented here can inform ongoing efforts to devise better macro-financial theory and real-world applications at a time when policymakers are still searching for new approaches in the aftermath of the Great Recession.