Price Z-Score

What it measures:

Measures how far the current closing price deviates from its rolling historical mean, expressed in standard deviations. Uses rolling Price Z-Scores to assess relative price extension and identify prices that are unusually high or low compared with their recent distribution.

How to interpret it:

• Z-Score > +2.0: Price is unusually high relative to its rolling mean and may be extended.
• Z-Score < -2.0: Price is unusually low relative to its rolling mean and may be depressed.
• Z-Score Between -1 and +1: Price is within one standard deviation of its rolling mean.
• Z-Score Near Zero: Price is close to its recent rolling mean.
• Rising Z-Score: Price is moving higher relative to its rolling mean and standard deviation.
• Falling Z-Score: Price is moving lower relative to its rolling mean and standard deviation.
• Comparison Across Windows: Shorter windows respond more quickly to price changes, while longer windows provide broader context for price extension.

Used for:

• Identifying unusually high or low prices relative to recent history.
• Detecting potential mean-reversion setups when combined with reversal confirmation.
• Assessing price extension within an established trend.
• Combining with Linear Regression Slope, moving averages, ADX, and momentum indicators to distinguish trend continuation from potential exhaustion.
• Generating normalized features for quantitative trading models and cross-asset analysis.

Limitations:

• A Z-Score beyond ±2.0 does not automatically imply a reversal or a BUY/SELL signal; prices can remain extended during strong trends.
• Price Z-Score measures deviation from a rolling price mean, not the statistical significance of returns or the probability of a future reversal.
• Results depend on the rolling window, standard deviation calculation, and market regime.
• Trending and non-stationary price series may produce persistent high or low Z-Scores.
• Volatility-regime shifts and extreme observations can distort the rolling mean and standard deviation.
• A near-zero Z-Score does not necessarily indicate a sideways market; price may be following a strong trend near its rolling mean.