Bias Complete Guide
BIAS Indicator
What is Bias?
The BIAS indicator, also known as the Rate of Deviation, is a momentum-based technical indicator that measures the percentage deviation of the current price from its Moving Average (MA). Popularized by technical analysis pioneers like Joseph Granville, it is rooted in the principle of mean reversion: the idea that prices tend to return to their average over time. When the price moves too far away from the moving average, the BIAS reaches extreme levels, suggesting a potential correction or reversal toward the mean. The indicator oscillates around a zero line. A positive BIAS value indicates the price is trading above the moving average, reflecting bullish momentum, while a negative value indicates the price is below the moving average, reflecting bearish momentum. Common parameter settings include 6, 12, and 24 periods, with 12 being a standard default for short-to-medium term analysis. To use it effectively, traders should identify historical extreme levels specific to the asset being traded, as volatility varies across markets. It is best used in conjunction with trend-following indicators to avoid 'catching a falling knife' during strong trending phases.
Signal Types
Overbought / Oversold
When BIAS reaches historical extreme positive levels, the asset is overbought; extreme negative levels indicate it is oversold.
Zero Line Crossover
A cross above zero indicates price has moved above the MA (bullish), while a cross below zero indicates price has dropped below the MA (bearish).
Divergence
When price makes a new high but BIAS fails to do so, it suggests weakening momentum and a potential trend reversal.
Related Indicators
FAQ
What are the standard 'extreme' levels for BIAS?
There are no universal levels, but for a 12-day BIAS, +/- 5% is often considered significant for stocks, while +/- 3% might be used for less volatile indices.
How does BIAS differ from the Moving Average itself?
The Moving Average shows the average price level, while BIAS quantifies the distance between the current price and that average as a percentage.
Can BIAS be used in a strong trending market?
In strong trends, BIAS can stay at extreme levels for a long time. It is safer to use it for mean reversion in ranging markets or as a secondary confirmation in trends.
Parts of this page (FAQ, introductions) are AI-assisted. Core data and statistics are algorithmically computed. All pattern definitions are human-reviewed.
Disclaimer: This page is based on publicly available market data and algorithmically generated technical analysis. It does not constitute investment advice. Historical pattern statistics do not guarantee future performance. Invest at your own risk.
Data source: EODHD · © 2026 KlineVision AI