I remember a professor of economics taking de-identified historic charts - no price or commodity/stock shown - blinded and asking 'chartist' staff to have a go at forecasting.
When the 'future' price action was overlaid it was obvious that the chartists were no better than 50:50 at guessing the real price action that followed.
These days because some traders and computer programs are looking for these patterns and trading based on them I think one can see some correlation to price action because of the herd effect of chartists/programs all creating short lived self fulfilling chart trading based action.
