19/04/2026
Dow Theory is a framework for analyzing market trends, originating from Charles H. Dow's editorials in the Wall Street Journal between 1900–1902, later codified by William Hamilton and refined by Robert Rhea. Edwards and Magee treated it as the bedrock of technical analysis. The theory defines three concurrent trends: the primary trend (lasting months to years, the major bull or bear market), the secondary reaction (lasting weeks to months, counter to the primary trend), and the minor trend (days to weeks, daily noise). Its most famous rule is that the Industrial Average and Transportation Average must confirm each other—a new high in industrials without a similar high in transports is a false signal.
The theory's practical essence is trend identification by peaks and troughs: an uptrend exists as long as each successive peak is higher than the prior peak, and each trough higher than the prior trough. The trend continues until a clear reversal occurs a peak followed by a trough that breaks the prior trough. Volume should expand in the direction of the primary trend. Edwards and Magee emphasized that Dow Theory does not predict when a trend will reverse; it only confirms that a reversal has occurred. For them, this discipline waiting for confirmation before acting was more valuable than any individual pattern.