"Just because we want there to be a policy response to a problem does not mean that the problem can be solved with the tools at hand. Again, if I have a hammer, it can be useful for all sorts of household tasks, but useless for repairing a leaky shower head – in fact, if I take the hammer to the shower head, I will probably make matters worse. I need a wrench to fix a pipe leak, and no amount of wishing will make a hammer a wrench. This is the essential reason why central bankers are now looking around for what has been called a ‘macroprudential instrument’, that is a tool suited to the job – and a tool additional to the one that we already have in our toolkit."
I am very sympathetic to this argument, interest rate is probably not the right tool to deal with asset price bubbles and using regulation or a 'macroprudential instrument' is the right thing to do.
However, we still need to ask the question: What if those instruments are not available or are simply failing to do their job? Is there a role for monetary policy? He cites the example of Spain as a country where the central bank was stressing the importance of dynamic provisioning for banks and still went through a real estate bubble. It might be that the Bank of Spain was not aggressive enough, but how do we know that the systems that we are setting in place now will take care of the next bubble or financial imbalance?
One can argue that interest rates should not be used to deal with an imbalance in financial markets, because this is not part of their mandate, but I think this is a very narrow view of the role of central banks. There is no doubt that imbalances in financial markets spread to the real economy. In fact, there were many signs of a macroeconomic imbalance prior to the crisis such as excessive consumption, current account imbalances. Aren't interest rates the tool to deal with macroeconomic imbalances?
If we apply Adam Posen's logic to some of the previous recessions, we could come up with the conclusion that central banks should never use the interest rate as a stabilizing tool. We could always claim that previous recessions originated in a specific sector of the economy and it would be better to deal with these developments using 'sector-specific' tools. Adam Posen uses as an example a procyclical tax on real estate that might avoid real estate bubbles like the one we just went through. We could apply the same logic to the internet bubble of the 90s and argue that a tax on internet-related companies would have avoided that bubble. This might be true but how do we know where the next bubble will come from so that we set up the right 'procyclical tax' to avoid it? In my view, if the next bubble generates a macroeconomic imbalance, then it is the role of monetary and fiscal policy to deal with it. The next business cycle, the next bubble is likely to be different from the current one and we will learn from it and set up additional policies to make sure that it does not happen again, but until we figure out policies to avoid any potential bubble or imbalance that can cause a recession, monetary policy still has a role to play. And yes, using a hammer to fix a pipe leak will be a challenge...