Central banking is easy during the good times. Play with interest rates every now and again while basking in the glory of it all. Policy has also been straightforward during the downturn. Drop rates to nothing and keep them there – perhaps dabbling in quantitative easing to look busy. Where it starts to get difficult is in the middle ground.

A slew of stronger-than-expected global manufacturing data, therefore, must be slightly disquieting for central bankers. Activity in January for the US, Europe and China is now well above 50 as measured by purchasing manager surveys, historically indicating expansion. Strength in the UK was particularly surprising given soggy fourth-quarter output numbers. Less of a shock is that Spain, Ireland and Greece lag behind an otherwise resurgent Europe, where manufacturing has been expanding for six months.

Robust economic data up the ante on policymakers. Those arguing for higher rates also point to inflation pressures. In the eurozone, for example, January purchase prices rose at their fastest rate in more than a year. Chinese input prices jumped to an 18-month high. Prices are also ticking up in the UK. This week, the Bank of England will probably leave rates at 0.5 per cent but may be buoyed enough to halt quantitative easing – for now.

But it might take more to convince central banks to start tightening. Surveys can be disconnected from reality. In the US, for example, the Institute of Supply Management's survey excludes small companies and therefore half the workforce. Finally, absolute levels of industrial activity are still depressed, even if rates of change are rebounding. Manufacturing employment in Europe fell for the 20th successive month in January. The really tough decisions are a while away yet.