Technical Indicators

⏱️ 26 min read Intermediate Level 2: Deep Dives

Technical indicators are mathematical calculations based on price, volume, or open interest. While popular among traders, their effectiveness is mixed—some provide useful signals, many are redundant, and none are magic bullets. Here's what actually works (and what doesn't).

⚠️ Critical Reality Check

No indicator predicts the future. They all use past data to describe what already happened. Indicators can help identify trends, overbought/oversold conditions, and momentum shifts—but they lag price action and generate false signals frequently. Professional traders use them as confirmation tools, not trading triggers.

Trend Following Indicators

Moving Averages (MA)

What it is: The average price over X periods. Most common: 50-day, 200-day.

Types:

  • Simple Moving Average (SMA): All periods weighted equally
  • Exponential Moving Average (EMA): Recent prices weighted more heavily

How traders use it:

  • Price above MA = uptrend; below = downtrend
  • Golden Cross: 50-day crosses above 200-day (bullish signal)
  • Death Cross: 50-day crosses below 200-day (bearish signal)
  • MA as dynamic support/resistance levels

Reality check: MAs are lagging indicators—they tell you a trend has already started. The crossover signals often come late, causing you to buy near tops or sell near bottoms. However, they're useful for defining trend direction and filtering trades (e.g., only buy when price is above 200-day MA).

📊 Research Finding

Studies show 200-day moving average strategies produce modest positive returns but underperform buy-and-hold after transaction costs and taxes. They work better in strongly trending markets than choppy sideways markets.

MACD (Moving Average Convergence Divergence)

What it is: Difference between two EMAs (typically 12-day and 26-day), plus a 9-day signal line.

Signals:

  • MACD crosses above signal line = bullish
  • MACD crosses below signal line = bearish
  • Divergence: Price makes new high but MACD doesn't (bearish divergence)

Strengths: Shows both trend direction and momentum. Widely watched, so becomes self-fulfilling at times.

Weaknesses: Lags significantly. Many false signals in choppy markets. Optimized parameters (12, 26, 9) were chosen arbitrarily decades ago.

Momentum Oscillators

RSI (Relative Strength Index)

What it is: Measures speed and magnitude of price changes on 0-100 scale. Standard period: 14 days.

Traditional interpretation:

  • Above 70 = overbought (potential reversal down)
  • Below 30 = oversold (potential reversal up)
  • Divergence between price and RSI signals reversals

Reality: In strong trends, RSI can stay "overbought" for months or "oversold" for weeks. Blindly selling at 70 or buying at 30 loses money in trending markets. RSI is more useful for:

  • Confirming weakness in uptrends (lower RSI highs)
  • Identifying divergences (price up, RSI down = warning)
  • Filtering trades in range-bound markets

⚠️ Common Mistake

Traders see RSI at 80 and think "time to sell!" In reality, RSI above 70 often indicates a strong uptrend that continues. The mantra: "The trend is your friend until it bends." Don't fight strong momentum just because RSI is elevated.

Stochastic Oscillator

What it is: Compares closing price to price range over 14 periods. Also uses 0-100 scale.

Similar to RSI: Values above 80 = overbought, below 20 = oversold.

Verdict: Highly redundant with RSI. Slightly more sensitive (more signals, but also more false signals). Most traders pick one oscillator, not both.

Volatility Indicators

Bollinger Bands

What it is: 20-day moving average with bands 2 standard deviations above and below.

How traders use it:

  • Price touching upper band = overbought
  • Price touching lower band = oversold
  • Bands squeeze together = low volatility (breakout coming)
  • Bands widen = high volatility

What actually works: Bollinger Bands are better for measuring volatility than predicting direction. The "squeeze" (narrowing bands) does often precede big moves, but it doesn't tell you which direction. Touching the upper band in a strong uptrend is normal, not a sell signal.

Better use case: Options traders use band width to gauge volatility for pricing strategies.

ATR (Average True Range)

What it is: Measures average volatility over 14 periods.

Best use: Setting stop-loss distances (e.g., 2x ATR below entry) rather than arbitrary percentages. Doesn't predict direction—purely a volatility measure.

Volume Indicators

Volume

Not a complex indicator, but the most important. Key principles:

  • Breakouts with high volume: More reliable
  • Breakouts with low volume: Often fail (false breakouts)
  • Price up + volume down: Weak rally (bearish divergence)
  • Price down + volume up: Strong selling pressure

Reality: Volume is one of the few indicators with real predictive value. It shows conviction. Always check volume before acting on price patterns or indicator signals.

On-Balance Volume (OBV)

What it is: Running total of volume (add on up days, subtract on down days).

Theory: OBV trends before price. If price makes new high but OBV doesn't, bearish divergence.

Verdict: Moderately useful but not dramatically better than just watching regular volume. More complexity than value added.

Lagging vs Leading Indicators

Type Indicators Best Use
Lagging Moving averages, MACD Trend confirmation, filtering trades
Leading RSI, Stochastic Divergence spotting (with caution)
Neither Volume, Bollinger Bands, ATR Volatility measurement, confirmation

The Indicator Trap

More indicators ≠ better results. Common mistakes:

  1. Indicator overload: Using 10 indicators that all say the same thing (redundant). RSI, Stochastic, and CCI are all momentum oscillators—pick one.
  2. Optimization bias: Back-testing until you find "perfect" settings that worked in the past. These settings fail going forward (curve-fitting).
  3. Ignoring context: Overbought/oversold signals work in ranges, fail in trends. Know the market regime.
  4. Treating indicators as holy grails: No indicator works all the time. They're tools, not crystal balls.

✅ What Professional Traders Actually Do

Most successful traders use 2-3 indicators maximum:

  • One trend indicator: 200-day MA or MACD
  • One momentum indicator: RSI
  • Volume: Always

Then they overlay fundamental context, market regime, and risk management. The edge isn't in the indicators—it's in discipline and risk control.

What the Research Shows

Academic studies on technical indicators:

  • Moving average crossovers: Small positive returns pre-1990s, near-zero post-2000 (arbitraged away)
  • RSI strategies: Work in some markets/periods, fail in others. No consistent edge after costs
  • MACD: Similar—occasional outperformance, but not reliable across markets/timeframes
  • Combined strategies: Using multiple indicators together improves accuracy slightly but increases false positives

Bottom line from research: Most indicator-based strategies struggle to beat buy-and-hold after transaction costs, taxes, and the emotional toll of frequent trading. Indicators work best as confirmation tools within a broader strategy—not as standalone trading systems.

Practical Guidelines

If you're going to use indicators:

  1. Keep it simple: 2-3 indicators maximum
  2. Avoid redundancy: Don't use 5 momentum oscillators
  3. Match indicator to market: Trend indicators for trending markets, oscillators for range-bound
  4. Volume first: Always confirm with volume
  5. Context matters: Overbought can stay overbought. Know the trend.
  6. Beware curve-fitting: Parameters that worked 2010-2020 may fail 2020-2030
  7. Risk management trumps all: Best indicator setup loses without proper stops

The Honest Truth

Most retail traders fail not because they use the "wrong" indicators, but because:

  • They overtrade (transaction costs destroy returns)
  • They lack discipline (override their system)
  • They have no edge (indicators alone aren't an edge)
  • They ignore risk management
  • They trade too large (blown out on inevitable losing streaks)

Indicators can't fix these problems. They're tools for describing what happened, not predicting what will happen. The pros who use them successfully do so within a comprehensive trading plan with strict risk controls.

💡 Alternative Perspective

Many successful investors ignore technical indicators entirely. Warren Buffett, Jack Bogle, and most institutional investors focus on fundamentals and long-term value. Technical analysis is one approach—not the only approach, and arguably not the best approach for most people.

Key Takeaways

  • Indicators describe past price action—they don't predict the future
  • Moving averages help define trends but lag price significantly
  • Oscillators (RSI, Stochastic) identify overbought/oversold but fail in strong trends
  • Volume is the most important confirmation tool
  • More indicators doesn't equal better results—keep it simple
  • No indicator works all the time; know when to use which tool
  • Academic evidence shows most indicator strategies underperform buy-and-hold after costs
  • Professional traders use indicators for confirmation, not as standalone signals
  • Risk management and discipline matter far more than indicator choice
  • Consider whether technical trading aligns with your goals vs passive investing