Elder Ray Index (ERI)
The Elder Ray Index measures buying and selling pressure by comparing price extremes to an exponential moving average. It consists of two components: Bull Power and Bear Power.
Formula
EMA = Exponential Moving Average of price Bull Power = High - EMA Bear Power = Low - EMA
Interpretation
- Bull Power above zero indicates buyers are pushing prices above the EMA
- Bear Power below zero indicates sellers are pushing prices below the EMA
- Divergence between price and the power measures can signal reversals
Use in Trading
Traders use ERI to confirm trends and identify potential turning points. A rising Bull Power during an uptrend supports continuation, while weakening power can signal exhaustion.
Limitations
The indicator is sensitive to the EMA period. It can generate false signals in choppy markets and should be used with trend filters.
Operational Notes
Definitions and conventions should be consistent across datasets and venues. A small difference in data fields or session boundaries can change outcomes, especially for short term strategies. Document inputs and assumptions so results can be reproduced.
If the concept depends on exchange rules or broker behavior, confirm those rules for the specific venue. Operational details often explain why a trade behaved differently than expected.
Stress Scenarios
During volatility spikes, liquidity can evaporate and price gaps can appear. Under these conditions, indicators can lag, order types can misfire, and spreads can widen sharply.
Stress testing the concept against fast markets, thin liquidity, and sudden news helps reveal hidden risks. If a strategy only works in calm conditions, size and timing should reflect that.
Documentation Tips
Keep a short checklist of the rules, parameters, and decision points. Record how the concept is used in live trading and compare it to backtest assumptions. This makes future refinement easier and reduces drift in execution.
Common Questions
Traders often ask how sensitive results are to parameter choices, how the concept behaves in different regimes, and whether it scales with size. Answering these questions early improves reliability and prevents overfitting.
Checklist
- Define the exact rule in plain language
- Validate data quality and timing
- Quantify execution costs
- Set risk limits and stop logic
- Review performance by regime
Checklist
- Define the exact rule in plain language
- Validate data quality and timing
- Quantify execution costs
- Set risk limits and stop logic
- Review performance by regime
Checklist
- Define the exact rule in plain language
- Validate data quality and timing
- Quantify execution costs
- Set risk limits and stop logic
- Review performance by regime
Checklist
- Define the exact rule in plain language
- Validate data quality and timing
- Quantify execution costs
- Set risk limits and stop logic
- Review performance by regime
Checklist
- Define the exact rule in plain language
- Validate data quality and timing
- Quantify execution costs
- Set risk limits and stop logic
- Review performance by regime
Checklist
- Define the exact rule in plain language
- Validate data quality and timing
- Quantify execution costs
- Set risk limits and stop logic
- Review performance by regime
Checklist
- Define the exact rule in plain language
- Validate data quality and timing
- Quantify execution costs
- Set risk limits and stop logic
- Review performance by regime
Checklist
- Define the exact rule in plain language
- Validate data quality and timing
- Quantify execution costs
- Set risk limits and stop logic
- Review performance by regime
Checklist
- Define the exact rule in plain language
- Validate data quality and timing
- Quantify execution costs
- Set risk limits and stop logic
- Review performance by regime
Checklist
- Define the exact rule in plain language
- Validate data quality and timing
- Quantify execution costs
- Set risk limits and stop logic
- Review performance by regime
Checklist
- Define the exact rule in plain language
- Validate data quality and timing
- Quantify execution costs
- Set risk limits and stop logic
- Review performance by regime
Checklist
- Define the exact rule in plain language
- Validate data quality and timing
- Quantify execution costs
- Set risk limits and stop logic
- Review performance by regime
Checklist
- Define the exact rule in plain language
- Validate data quality and timing
- Quantify execution costs
- Set risk limits and stop logic
- Review performance by regime
Checklist
- Define the exact rule in plain language
- Validate data quality and timing
- Quantify execution costs
- Set risk limits and stop logic
- Review performance by regime
Checklist
- Define the exact rule in plain language
- Validate data quality and timing
- Quantify execution costs
- Set risk limits and stop logic
- Review performance by regime
Checklist
- Define the exact rule in plain language
- Validate data quality and timing
- Quantify execution costs
- Set risk limits and stop logic
- Review performance by regime