What did investors learn from Yellen's Boston speech?

Fed chair Janet Yellen's recent speech in Boston was an occasion to put into perspective a few important questions regarding the still high economic output gap, the formation of inflation expectations, the sensitivity of wages to labour conditions or the interaction between major central banks' monetary policies.

Unfortunately, most of them did not come with precise answers, leaving investors in the dark on these topics. Yellen mentioned for the first time the possibility to let the economy temporarily overheat in order to encourage business spending, better job distribution and ultimately boost productivity but again there was nothing conclusive here. It seems that the coming decisions will continue to be data dependent and a showdown between two increasingly polarised camps at the FOMC. In that sense, the Boston speech provided arguments for both sides. What was in my view more critical l...