The market in general moves as a whole, down to the minute level. What this means is that any technical analysis that applies only to an individual stock has no value. If you overlay the intraday charts of any two S&P500 stocks, you will see that they are highly positively correlated. Any negative correlations are short lived, unless a major event happens that affects only one of the stocks. This is unlikely, as a major shift in the price of IBM, for example, will definitely affect the whole market. Thus, we can conclude that any negative correlations on the chart are simply unpredictable, random noise. This positive correlation, to me, provides strong evidence that the bulk of TA is fruitless. We can go through individual technical indicators to show how they have no real-world foundation. Closing of the gap: Because the market moves as a whole, an individual stock has absolutely no reason or ability to close it's own gap. Gaps are only closed when the general market moves in that direction, for completely different reasons. Most trendlines: Any trendline that neatly connects the highs or lows of an individual stock is an illusion. One could draw generally the same line on 500 other stocks, but some of these lines will be curved, have a different slope, or be generally ugly. Volume: The volume formation on a particular stock will be roughly similar to every other stock at the same time. Any differences between the volume patterns of the two stocks are just noise. Head and Shoulders: The neckline on a head and shoulders pattern is far too precise to have meaning. The market likes to be "fuzzy" in a way; it rarely reverses at an exact point because the differences between S&P500 stock A and stock B are simply noise. Range & Channel breakouts: A nice, neat range breakout could appear on the chart for a particular stock, but it might be nonexistent for 500 other similar stocks. Support and Resistance: Individual stocks cannot have meaningful support and resistance, because the market moves as a whole. The only real S&R is that which exists for the market as a whole. Yesterday's H/L/C: These points are absolutely worthless in serving as support and resistance. They are arbitrary and have no meaning for the whole market. --- I am not saying that technical analysis does not work. My point is only that TA traders need to be able to distinguish noise from real substance in the market. The biggest trap one can fall into is to start seeing something that is not there. If you are trading an S&P500 stock, only pay attention to price moves that are also apparent in the average itself. Any negative correlation is the accumulation of random trades placed by random people at random time periods. TL,DR: Every stock in the SP500 is highly positively correlated. Negative correlations are almost always noise. A price/volume pattern that has meaning and is not noise should be apparent on almost all stocks collectively. Please correct me if i'm wrong.