Low-Lag Trend Timing with a Second-Order Low-Pass Filter

Summary

The note explains the low-lag trend line (LLT) as a timing indicator derived from signal processing. It frames moving averages as low-pass filters: they smooth short-term price fluctuations while retaining slower trend movement. LLT applies a second-order low-pass filter to seek a compromise between the smoothness of long moving averages and the responsiveness of short ones.

The cited research and the author’s chart comparison report that LLT follows prices more closely and reduces delay relative to conventional moving averages. A backtest using an LLT parameter of 0.05 did not outperform the index, so the note presents the indicator mainly as a useful way to rethink trend signals rather than as proof of a profitable strategy. LLT still lags prices, and its behavior depends on filter settings, leaving scope for further evaluation and parameter testing.

Key ideas

• Moving averages can be understood as low-pass filters that suppress high-frequency price changes.
• LLT uses a second-order filter to reduce lag while retaining trend smoothing.
• The note reports closer price tracking than conventional moving averages in its comparisons.
• Its cited backtest did not beat the index, and LLT still has some lag.

Tags

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