Thus, for accountability and effective communication, “numbers” or statistics become increasingly important. Moreover, data here means not only quantitative data; qualitative data are equally as important. Knowns and unknowns in Central Bank policy To understand the nature of the economic information central banks want to know, the following three-way classification may be helpful. The first type of information concerns “known knowns”.
Here “knowns” are whatever happened in the past. Thus, known knowns are information about what happened, and typical known knowns are contained in statistics. The second type is “known unknowns”. Here unknowns are those things that are happening at present or that will emerge in the future. They are known unknowns, since we already know that they are happening or will happen.