The Federal Reserve Open Market Committee (FOMC) adopted the most recent („threshold“ or state contingent) incarnation of its forward guidance policy in September 2012 (with the Bank of England following suit in August 2013). See http://www.newyorkfed.org/research/staff_reports/sr652.pdf, http://www.bankofengland.co.uk/monetarypolicy/Pages/forwardguidanceexplained.aspx, http://www.bankofengland.co.uk/publications/Documents/inflationreport/2013/ir13augforwardguidance.pdf. BIS central bankers’ speeches  7  Forward guidance, therefore, has not transformed the fundamental requirements of effective communication. Recent experience has demonstrated this vividly.
Having established an expectation of tapering in September 2013, the Federal Open Market Committee then confounded expectations by not doing so. Interest rate volatility, particularly in longer-term bonds, was exaggerated, along with spillover in exchange rate movements for a number of countries.