# Technical Analysis from A to Z

by Steven B. Achelis

MASS INDEX

Overview

The Mass Index was designed to identify trend reversals by measuring the narrowing and widening of the range between the high and low prices. As this range widens, the Mass Index increases; as the range narrows the Mass Index decreases.

The Mass Index was developed by Donald Dorsey.

Interpretation

According to Mr. Dorsey, the most significant pattern to watch for is a "reversal bulge." A reversal bulge occurs when a 25-period Mass Index rises above 27.0 and subsequently falls below 26.5. A reversal in price is then likely. The overall price trend (i.e., trending or trading range) is unimportant.

A 9-period exponential moving average of prices is often used to determine whether the reversal bulge indicates a buy or sell signal. When the reversal bulge occurs, you should buy if the moving average is trending down (in anticipation of the reversal) and sell if it is trending up.

Example

The following chart shows Litton and its Mass Index.

A 9-day exponential moving average is plotted on top of Litton's prices. I drew arrows when a reversal bulge occurred (i.e., the Mass Index rose above 27 and then fell below 26.5). If the 9-day moving average was falling, I drew a "buy" arrow. If the 9-day moving average was rising, I drew a "sell" arrow.

You can see that the signals generated by the Mass Index during this time period occurred a few days before the trend reversed.

Calculation

- Calculate a 9-day exponential moving average ("EMA") of the difference between the high and low prices.

- Calculate a 9-day exponential moving average of the moving average calculated in Step 1.

- Divide the moving average calculated in Step 1 by the moving average calculated in Step 2.

- Total the values in Step 3 for the number of periods in the Mass Index (e.g., 25 days).

*Technical Analysis from A to Z*is reproduced here with permission from the author and publisher.

### Contents

- Preface
- Acknowledgments
- Terminology
- To Learn More
- Bibliography
- About the Author
- Technical Analysis
- Price Fields
- Charts
- Support & Resistance
- Trends
- Moving Averages
- Indicators
- Market Indicators
- Line Studies
- Periodicity
- The Time Element
- Conclusion
- Absolute Breadth Index
- Accumulation/Distribution
- Accumulation Swing Index
- Advance/Decline Line
- Advance/Decline Ratio
- Advancing-Declining Issues
- Advancing, Declining, Unchanged Volume
- Andrews' Pitchfork
- Arms Index
- Average True Range
- Bollinger Bands
- Breadth Thrust
- Bull/Bear Ratio
- Candlesticks - Japanese
- CANSLIM
- Chaikin Oscillator
- Commodity Channel Index
- Commodity Selection Index
- Correlation Analysis
- Cumulative Volume Index
- Cycles
- Demand Index
- Detrended Price Oscillator
- Directional Movement
- Dow Theory
- Ease of Movement
- Efficient Market Theory
- Elliott Wave Theory
- Envelopes (Trading Bands)
- Equivolume/Candlevolume
- Fibonacci Studies
- Four Percent Model
- Fourier Transform
- Fundamental Analysis
- Gann Angles
- Herrick Payoff Index
- Interest Rates
- Kagi
- Large Block Ratio
- Linear Regression Lines
- MACD
- Mass Index
- McClellan Oscillator
- McClellan Summation Index
- Median Price
- Member Short Ratio
- Momentum
- Money Flow Index
- Moving Averages
- Negative Volume Index
- New Highs-Lows Cumulative
- New Highs-New Lows
- New Highs/Lows Ratio
- Odd Lot Balance Index
- Odd Lot Purchases/Sales
- Odd Lot Short Ratio
- On Balance Volume
- Open Interest
- Open-10 TRIN
- Option Analysis
- Overbought/Oversold
- Parabolic SAR
- Patterns
- Percent Retracement
- Performance
- Point & Figure
- Positive Volume Index
- Price and Volume Trend
- Price Oscillator
- Price Rate-of-Change
- Public Short Ratio
- Puts/Calls Ratio
- Quadrant Lines
- Relative Strength, Comparative
- Relative Strength Index
- Renko
- Speed Resistance Lines
- Spreads
- Standard Deviation
- STIX
- Stochastic Oscillator
- Swing Index
- Three Line Break
- Time Series Forcast
- Tirone Levels
- Total Short Ratio
- Trade Volume Index
- Trendlines
- TRIX
- Typical Price
- Ultimate Oscillator
- Upside/Downside Ratio
- Upside/Downside Volume
- Vertical Horizonal Filter
- Volatility, Chaikin's
- Volume
- Volume Oscillator
- Volume Rate-of-Change
- Weighted Close
- Williams' Accumulation/Distribution
- Williams' %R
- Zig Zag