Using the Fractal Dimension Index to Detect Market Regimes

Summary

The document presents the Fractal Dimension Index (FDI) as a way to distinguish directional price behavior from choppy conditions. It describes measuring the geometric roughness of a price curve over a rolling window: values nearer 1 indicate a smoother, more directional path, while values nearer 2 indicate a more erratic path. The proposed decision point is 1.5. Below that level, the method suggests considering momentum or breakout systems; above it, it suggests mean-reversion logic or pausing trading.

The FDI is framed as a regime filter that can override the strategy selection of other trading systems. The document offers a conceptual explanation, but no formula, sample data, backtest, or performance evidence. Its claims that the threshold confirms trend conditions and that trend strategies will be chopped up in noise are not substantiated here. The reading also does not discuss window selection, instrument differences, threshold sensitivity, or how to handle borderline and rapidly changing readings. Treat the suggested threshold and strategy mapping as proposals to test, not established guarantees.

Key ideas

• The FDI estimates price-path roughness over a rolling window.
• Values nearer 1 are associated with smoother directional movement, while values nearer 2 indicate greater irregularity.
• The document proposes 1.5 as a boundary between trending and choppy regimes.
• It recommends momentum or breakout systems below the boundary and mean-reversion or inactivity above it.
• The document provides no empirical validation for its threshold or trading recommendations.

Tags

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.