4.4 High Noise Markets Are Mean-Reversion Markets
High noise is mean-reversion fuel: motion that cancels out keeps returning to center. The danger is a flip to trend, so gate fades on the efficiency ratio and stop at the MAE edge.
Independent research on systematic & quantitative trading
Aligrithm is an independent research publication on systematic trading, quantitative research, market microstructure, and adaptive systems. Long-form essays, code notebooks, and architecture breakdowns across eight pillars, built for traders who care more about how markets behave than about hype.
More about the publication →The ten pillars
Read in order. Each pillar walks you out of one trap with one new ability. The newest article is the worst place to begin.
- 1 The Scientific Trader Rebuild what you accept as evidence. Every rule becomes a hypothesis, every backtest an experiment you can falsify. 28
- 2 Indicator Engineering The input decides the ceiling. Build features with measurable properties that survive the tests. 82
- 3 Robust Systems Lab A strategy is not robust for surviving one friendly backtest. Here it survives hostile testing. 44
- 4 Market Structure Notes The same rule is edge on one instrument and noise on another. Read a market's personality before you deploy. 77
- 5 Microstructure Alpha The order-book layer. The same signal is worthless as taker flow and valuable as a maker improvement. 53
- 6 Portfolio Construction & System Death A real signal still loses if the size and correlations are wrong. Sizing is part of the signal. 59
- 7 Python Research Notebooks Stop taking results on faith. Re-run every claim on your own data and see whether it holds. 5
- 8 Physics, Geometry & Event-Driven Markets The frontier. Markets as event-driven nonlinear systems, not fixed-time price series. Read it last. 12
- 9 Prediction Market Arbitrage The cleanest money on Polymarket and Kalshi comes from prices that contradict each other, not prices that turn out wrong. 42
- 10 Cross-Sectional & Factor Investing Stop timing one asset. Rank the whole cross-section and let relative value, not direction, carry the return. 22
Latest articles
4.3 How to Rank Markets by Trend Quality
Stop keeping the best backtest Sharpes from a big universe; they are partly luck. Rank markets by trend quality first, allocate trend systems to the top and mean-reversion to the bottom.
4.2 Efficiency Ratio Explained for Traders
The efficiency ratio is net change over total path, between 0 and 1. It measures how much of a market's motion became direction. Read it at your trading horizon, then pick your strategy family.
4.1 Noise Is Not Volatility
Two markets can show identical volatility and opposite tradeability. Volatility measures how far price moves; noise measures how much cancels out. Trade the noise axis, not the variance.
3.32 The Backtest Integrity Checklist
The deployment-readiness artifact: 32 items in 7 categories. Each box backed by analysis, reviewed by a second pair of eyes. Failures block or constrain.
3.31 Why Transaction Costs Should Be Added Before You Fall in Love
Apply realistic costs from Stage 2, not at the end. HFT strategies are cost-dominated; low-frequency edge-dominated. Teams that fall in love with pre-cost numbers resist the post-cost reality.
3.30 How to Evaluate a Strategy Beyond Net Profit
A strategy is more than net profit. The evaluation panel has 25 metrics across 7 categories. The panel reveals the failure axis. Headline numbers project away the operational info. Report all 25.
3.29 Why Profit Factor Can Lie
Profit factor is dominated by extreme trades. Two strategies at PF 2.0 can have very different OOS prospects. Report trimmed PF and Gini of trade P&L alongside the headline. Don't optimize on PF.
3.28 MAE/MFE Analysis: Seeing What Net Profit Hides
MAE is the largest unrealized loss; MFE the largest unrealized gain. Plots reveal what aggregates hide: bounceback rates, profit capture, exit timing. Compute before adding stops or profit targets.
3.27 When a Stop Loss Improves Risk but Destroys Edge
A stop loss truncates losses (lowers drawdown) and cuts winners that briefly moved against entry (lowers expectancy). Mean reversion: second effect dominates. Trend following: first does. Test it.
3.26 The Hill, the Spike, and the Cliff: Reading Optimization Surfaces
Optimization surfaces are hills, spikes, or cliffs. Hill: pick the center, deploy. Spike: reject. Cliff: pick away from the boundary. Same IS Sharpe; very different OOS. Read the shape.
3.25 Parameter Stability Beats Best Parameter
The IS-optimum is the peak. The plateau is a wide region of similar Sharpes. Pick the plateau center. Peak inherits search-width bias; plateau does not. Lower IS, higher OOS. Pick the plateau.