In the eyes of some Federal Reserve watchers, Fed chief Janet Yellen has become a master of making every public appearance a bit of a Rorschach test, giving fans and critics alike just enough of what they want to hear to reinforce their pre-existing viewpoints. Her semi-annual Humphrey-Hawkins testimony on Fed monetary policy before Congress this week was another prime example of this, with Wall Street types hopeful of a rise in interest rates sometime later this year, and contrarians increasingly unconvinced and dismissive. For instance, labor markets are showing...