Technical Analysis in Stock Trading: Charts, Patterns, and Indicators

Reading Price as Language

Charles Dow began publishing the Dow Jones Industrial Average in 1896 and wrote a series of Wall Street Journal editorials that became the first systematic articulation of what we now call Dow Theory. His core observation was that market prices move in trends, and those trends can be identified and traded. Technical analysis — the practice of forecasting price movements from historical price and volume data — descends directly from Dow's work, refined over more than a century into a rich vocabulary of patterns and indicators.

The Foundational Premise

Technical analysis rests on three core assumptions articulated by technical analysts since Dow's era.

• The market discounts everything — all known information, including fundamentals, investor psychology, and macroeconomic data, is already reflected in the price
• Prices move in trends — once established, a trend is more likely to continue than to reverse; this persistence is the engine of technical trading
• History repeats — price patterns observed in the past tend to recur because human psychology (greed and fear) drives market behavior in predictable ways

Critics, particularly adherents of the Efficient Market Hypothesis, argue that technical patterns are self-fulfilling at best (they work only because enough traders believe they do) and random noise at worst. Academic research on the predictive power of technical signals is mixed, with most rigorous studies finding weak or inconsistent evidence after transaction costs.

Chart Types

Traders use several chart formats to visualize price data. The most informative is the candlestick chart, developed in Japan by rice traders in the 18th century and popularized in the West by Steve Nison in his 1991 book Japanese Candlestick Charting Techniques.

Each candlestick represents one trading period (1 minute, 1 day, 1 week, etc.). A green (or white) body means the close was above the open. A red (or black) body means the close was below the open. The wicks (shadows) show the period's high and low.

Support, Resistance, and Trend Lines

Support is a price level where buying interest has historically been strong enough to halt a decline. Resistance is a level where selling pressure has historically capped advances. These levels become self-reinforcing because many traders watch the same price history and place orders near the same zones.

• A broken support level often becomes resistance, and vice versa — the role reversal principle
• The more times a level has been tested without breaking, the more significant it is considered
• Trend lines connect successive higher lows (uptrend) or lower highs (downtrend) and serve as dynamic support and resistance
• A break below a rising trend line, especially on high volume, is interpreted as a potential trend reversal signal

Moving Averages

A moving average smooths out price noise by calculating the average closing price over a specified number of periods. Two types dominate technical analysis.

The 50-day and 200-day SMAs are among the most-watched levels on Wall Street. When the 50-day SMA crosses above the 200-day SMA, it is called a Golden Cross — widely interpreted as a bullish signal. The opposite — the 50-day falling below the 200-day — is called a Death Cross, seen as bearish. Both signals attracted significant media attention during the S&P 500's 2020 COVID crash and recovery.

Momentum Indicators: RSI and MACD

Momentum indicators measure the speed and direction of price changes rather than price level. The two most widely used are the Relative Strength Index (RSI) and the Moving Average Convergence Divergence (MACD).

The RSI, developed by J. Welles Wilder Jr. and published in his 1978 book New Concepts in Technical Trading Systems, ranges from 0 to 100. Readings above 70 are considered overbought (potential sell signal), while readings below 30 are considered oversold (potential buy signal). Divergence — when RSI makes a new high or low that the price does not confirm — is treated as an early warning of trend reversal.

MACD measures the relationship between two exponential moving averages (typically 12-period and 26-period EMA). The MACD line equals the 12-EMA minus the 26-EMA. A 9-period EMA of the MACD line is called the signal line. When MACD crosses above the signal line, it generates a bullish signal; crossing below generates a bearish one.

Chart Patterns

Technical analysts catalog recurring price formations that historically precede specific price movements. These patterns fall into two categories.

• Continuation patterns — suggest the existing trend will resume after a consolidation period. Examples: flags, pennants, ascending/descending triangles, cups-with-handles
• Reversal patterns — suggest the trend is about to change direction. Examples: head-and-shoulders (bearish reversal), inverse head-and-shoulders (bullish reversal), double tops, double bottoms, rounding bottoms

The head-and-shoulders pattern — characterized by three peaks, with the middle peak (head) higher than the two outer peaks (shoulders) — is one of the most studied patterns in technical analysis. The pattern is confirmed when price breaks below the neckline (the level connecting the two troughs between the peaks). Research published in the Journal of Finance by Lo, Mamaysky, and Wang (2000) found that several technical patterns, including head-and-shoulders, added statistically significant information to stock return forecasts.

Volume Analysis

Volume — the number of shares or contracts traded in a period — confirms or contradicts price moves. A price breakout to new highs on heavy volume is considered more reliable than one on light volume. A trend that persists on declining volume may signal weakening momentum. Volume-based indicators like On-Balance Volume (OBV), developed by Joseph Granville in 1963, cumulate volume on up days and subtract it on down days, tracking whether volume supports or diverges from price direction.

Limits of Technical Analysis

Technical analysis does not explain why prices move — only patterns in how they have moved. It provides no insight into a company's earnings quality, competitive position, or industry dynamics. Most professional portfolio managers use both fundamental and technical analysis, treating technical signals as timing tools layered on top of fundamental stock selection rather than as a standalone system.

This article is for informational purposes only and does not constitute financial advice.