Sometimes more than one low point can be used to form the neckline. As the head and shoulders pattern unfolds, volume plays an important role in confirmation. Ideally, but not always, volume during the advance of the left shoulder should be higher than during the advance of the head. This decrease in volume along with new highs that form the head serve as a warning sign. The next warning sign comes when volume increases on the decline from the peak of the head.
Final confirmation comes when volume further increases during the decline of the right shoulder.
The head and shoulders pattern is not complete and uptrend is not reversed until neckline support is broken. Ideally, this should also occur in a convincing manner with an expansion in volume. Sometimes, but certainly not always, the price will return to the support break and offer a second chance to sell. This distance is then subtracted from the neckline to reach a price target. Any price target should serve as a rough guide and other factors should be considered as well.