Definition
A chart pattern is a distinctive shape that price traces out over time on a chart — a head-and-shoulders, a triangle, a double top, a flag, and many others. Technical analysts catalogue these shapes because each one tends to be followed by a characteristic kind of move, whether a continuation of the existing trend or a reversal of it.
Patterns are built from the raw record of supply and demand. They emerge because crowds of traders react to price in repeatable, emotionally driven ways. A pattern is therefore a visual summary of market psychology — a record of how buyers and sellers negotiated, hesitated, and ultimately resolved a period of uncertainty.
Why it matters
How it works
To use a chart pattern, an analyst first identifies the shape as it forms, then waits for confirmation — typically a breakout beyond the pattern's boundary, ideally on rising volume. The pattern also supplies a measured price target, derived from its own dimensions, and a level at which the idea would be considered invalid.
Patterns are descriptive, not deterministic. Books such as the Encyclopedia of Chart Patterns assign each formation statistical performance figures — how often it reaches its target, how often it fails — precisely because outcomes vary. The value of a pattern lies in tilting probabilities, not in predicting the future.