Some people claim that there is no real relationship between the past movement of prices and the future movement of prices, making technical analysis invalid. However, it is easy to see that there are patterns in prices that can be used to predict market movements via technical analysis. There are several theories as to why this is true. One is that chart patterns display the action inherent in an auction market and thus provides predictive value. Another is that orders cluster around psychologically important levels. And some theorize that technical analysis is a form of self-fulfilment in that because many traders believe prices should reverse or continue at certain levels, they do.