In June 2014 it looked as though Federal Reserve chairman, Janet Yellen, would again seek to calm speculation that a rates rise was imminent. But some observers were anxious to look not at what Ms Yellen was saying, but at what she had actually done.
BlackRock, the world's largest fund manager, was a case in point. It had developed a tool for use internally which it had nicknamed the "Yellen Index". It blends together economic indicators which the Fed chair has referenced as important considerations for policy makers, together with unemployment and inflation targets already set out by the Fed.
By its own measures US monetary tightening was already overdue.