The head and shoulders formation is a widely used indicator and as such is vulnerable to the market's need to frustrate the most people possible. So I need some hard-rule confirmations so I won't get whipsawed in this market.
This is why according to Smita Sedana (an amazingly smart person posting on Minyanville - my favorite site/blog/etc...), "volume is very important in this pattern. The pattern is consumated on a close below the neckline by about 3%. Pattern confirmation would only happen after a decisive break of the bottom Bolinger Band, 50-dma, and 200-dma."
Her chart is included which is also a glance at the SP-500 right now.