Due to immense and unrelenting political pressure, central banks the world over have mispriced capital at gargantuan scales. This has led to immense distortions in capital markets.
The level of central bank intervention has only grown in the past 30 years. So the resulting economic growth or slowdown is measurably different than before.
Anecdotally, look at the following to see one example of capital distortion in action:
The Swiss National Bank digitally printed an enormous amount of Swiss Francs and bought Euros in order to peg their currency lower (didn't work). They used this excess of digitally printed capital to buy real capital assets such as global equities.
A question to ponder: what is the fair market price of global equities when some buyers can print money? Does it matter?
http://www.bloomberg.com/news/articles/2015-05-06/snb-boosts... "The SNB stands out among major central banks for its equity investments. It had 522 billion francs ($572 billion) of foreign exchange reserves at the end of March, acquired due to interventions to defend the currency cap of 1.20 per euro it had in place from 2011 to early 2015."
Swiss National Bank's Portfolio 6/30/2015: http://www.nasdaq.com/quotes/institutional-portfolio/swiss-n...