It is my firm belief that the smart money trades at periods of low volatility and positions itself for moves as opposed to reacting to moves. This is the reasoning for me anyway as to why I prefer to trade on the shorter histograms--it is kind of the same theory as Bollinger Band tightening prior to a larger move. Granted, a large tall histogram can reverse itself into a big move, but I believe it is more rare. It usually takes the taller histogram time to settle down and get to a point where the direction becomes clearer and higher probability. Some of this flies in the face of Romik's WRB observation, but WRB has some good potential as well. I prefer a NRB to the WRB as long as the open is near one end and the close is near the other .