Themes for 2015: As QE spreads, could emergency medicine become the norm?

The US has ended QE without serious damage, even in emerging markets. But Japan is going for it with abandon, and the eurozone is very likely to start buying government bonds. This unconventional policy is becoming common – but its effects and even how it works are still hardly understood. Markets will be fixated on central bank policy again in 2015, but whether the doctors in Frankfurt and Tokyo can actually revitalise limping economies is far from sure. Jon Hay reports.