Direct Answer
Elder Ray Index is a momentum measure used to measure the speed, persistence, or relative intensity of recent price movement. The production page must define the exact calculation convention before interpreting higher or lower readings, because platform and provider implementations can differ.
Elder Ray Index: Formula, Meaning, Signals, Examples and How to Use It
How Is Elder Ray Index Calculated?
Alexander Elder's Elder-Ray splits buying and selling pressure relative to a trend proxy, a 13-period exponential moving average of close. Bull Power measures how far highs reach above it and Bear Power how far lows fall below it.
Formula: Bull Power = High - EMA(Close, 13); Bear Power = Low - EMA(Close, 13)
Inputs:
- High, low and close of each bar
- 13-period exponential moving average of close
Worked example. A bar with a high of 105 against a 13-period EMA of 102 has Bull Power of 3.00. The inputs are illustrative numbers, not market data.
Reading it. Positive Bull Power means buyers pushed price above the average; negative Bear Power means sellers pushed it below. Elder pairs the readings with the slope of the EMA, so power readings are interpreted in the direction of the trend.
Limits. Both measures are in price units, so they are not comparable across instruments. The EMA lags, and the power values carry no fixed overbought or oversold levels.
Indicator overview
| Attribute | Value |
|---|---|
| Category | Momentum |
| Asset classes | Stocks, ETFs, Indexes, Futures, Forex, Crypto, Commodities |
| Output type | Ratio/index/scalar |
| Parameters | Varies by implementation; document exact settings on use |
What is Elder Ray Index?
Elder Ray Index is a momentum measure used to measure the speed, persistence, or relative intensity of recent price movement. The production page must define the exact calculation convention before interpreting higher or lower readings, because platform and provider implementations can differ.
For Swoopr, the canonical profile separates definition, calculation, interpretation and decision use. That keeps readers from collapsing a descriptive metric into a trading strategy. An indicator can describe trend, momentum, volatility, participation, positioning or risk without providing a complete entry, exit, sizing or portfolio decision.
What does it measure?
Elder Ray Index measures specific market properties in the Momentum domain. The practical value is repeatability: the same inputs and formula can be applied across a defined dataset, allowing users to compare readings through time or across instruments when the calculation convention is held constant.
How to read Elder Ray Index
Interpretation depends on the market property being measured. A descriptive reading is not automatically predictive. The same numerical state can lead to different outcomes in a strong trend, quiet range, event-driven gap or illiquid market. Always combine with context from price structure, volume, and broader market regime before drawing conclusions.
Strengths
- Measuring highs and lows against the same 13-period EMA shows buying reach and selling reach as two distinct series rather than one net number.
- Each power value is read against a single trend reference, so the two lines show how far each extreme of the bar strays from it.
- Reproducible when the formula and data convention are fixed.
Weaknesses and limitations
- Bull Power uses only the high and Bear Power only the low, so a wide-ranging bar with a middling close can push both lines at once.
- The 13-period EMA is the only anchor, and a different span moves the zero line and so changes both readings together.
- Correlated indicators can create false confidence by repeating the same underlying information.
Editorial and risk note
This page is educational content, not individualized investment advice. It should not imply guaranteed prediction, accuracy or outperformance. Where multiple valid definitions exist, Swoopr states the alternatives and the reason for selecting its primary convention.
Frequently Asked Questions
Is Elder Ray Index a buy or sell signal?
No. Positive Bull Power means buyers pushed price above the average; negative Bear Power means sellers pushed it below. Both measures are in price units, so they are not comparable across instruments. A trade built on it still needs a trigger, an invalidation rule, a position size and realistic execution assumptions.
What is the best setting for Elder Ray Index?
Elder Ray Index takes these inputs: high, low and close of each bar; 13-period exponential moving average of close. There is no universal best setting for the tunable ones, so test them across instruments, regimes and out-of-sample periods and favor stable parameter regions over one historical winner.
Can Elder Ray Index be used by itself?
Both measures are in price units, so they are not comparable across instruments. The EMA lags, and the power values carry no fixed overbought or oversold levels. For that reason it is read next to measures of direction, participation, valuation, liquidity and risk, not alone.
Does Elder Ray Index work on every timeframe?
The calculation (Bull Power = High - EMA(Close, 13); Bear Power = Low - EMA(Close, 13)) can be run on any bar size, but behavior is not portable: a reading on a five-minute chart describes a very different market window from the same reading on a daily chart. Validate the exact timeframe before relying on it.
Why does Elder Ray Index give false signals?
Bull Power uses only the high and Bear Power only the low, so a wide-ranging bar with a middling close can push both lines at once. The 13-period EMA is the only anchor, and a different span moves the zero line and so changes both readings together. Lag, noise and regime changes add to this, because market participants react to new information after the reading is calculated.
How should Elder Ray Index be backtested?
Rebuild Elder Ray Index from high, low and close of each bar using point-in-time data, write the rules before testing, include delisted securities where relevant, model realistic fills and costs, reserve a validation sample and compare with a simpler baseline.