A Bloomberg survey of 63 economists covering central banks in the euro area, Switzerland, Denmark, Sweden and now Japan has found that rates below zero are thought to work better in smaller, open economies dealing with foreign exchange challenges, rather than in larger ones hoping to boost growth or stem falling prices.

Ninety percent of economists gave the Danish Nationalbank a thumbs up, while 70 percent were bullish regarding the Swiss National Bank's experience. The similarities between the two are clear; both are based in relatively open economies, and implemented negative rates to help manage their currencies.

The European Central Bank lowered its deposit rate below zero in 2014 as part of President Mario Draghi's multipronged attempt to avoid deflation and boost lending. Inflation dipped below zero four times last year and policymakers say it will probably do so again in coming months. It is therefore understandable why three-fifths of economists rated the ECB's policy as ineffective.