How to best represent forecast uncertainty is still the subject of intensive discussions in the Eurosystem, and a final decision has yet to be taken. Furthermore, it should be taken into account that forecast uncertainty may vary markedly over time, so that neither past forecast uncertainty nor the forecast uncertainty derived from models is always a good basis for assessing current forecast uncertainty.
This is one of the reasons why the forecast uncertainty conveyed by the ranges of the Eurosystem staff projections may be supplemented with a qualitative assessment by the ECB Governing Council. (For example, in December 2008, when year-end uncertainty was rising, the Governing Council concluded that in its “view …, the economic outlook remains surrounded by an exceptionally high degree of uncertainty.”).