Bid-Ask

Interpreting the bid/ask spread requires different skill sets than reading changing prices on the ticker tape. This poorly understood supply/demand engine compresses and expands constantly, responding to shifting market conditions. But most spread movement reveals nothing more than pure noise and has little directional value. While scalpers can use these frequent choppy periods to grab quick profits, technical traders should stand aside and wait. Directional signals will erupt from the spread regularly and allow them more rewarding entries.

Bid-Ask Article