These are either known knowns (type 1), or known unknowns (type 2). Statistics provide valuable information about known knowns, and they become the foundation for estimating known unknowns. However, statistics are grossly insufficient when it comes to detecting unknown unknowns (type 3).
Central-bank policy makers are frequently frustrated by deficiencies in the statistics available, which they find inadequate in helping them detect potential problems in the economy. Perceived deficiency is especially keen in financial information. It should be noted that financial stability is now seen as a prerequisite for economic stability.