https://therefutation.com/ Honest quant research: how to tell a real trading edge from a statistical mirage. Education and data-journalism only. en Mon, 14 Jul 2026 00:00:00 GMT https://therefutation.com/essays/statistical-mirages-in-trading/ https://therefutation.com/essays/statistical-mirages-in-trading/ Mon, 14 Jul 2026 00:00:00 GMT Search enough parameters across enough assets and something always looks profitable. How backtest overfitting manufactures fake edges — and the honest out-of-sample tests that expose them. https://therefutation.com/essays/survivorship-bias-in-backtesting/ https://therefutation.com/essays/survivorship-bias-in-backtesting/ Mon, 14 Jul 2026 00:00:00 GMT Survivorship bias makes backtests look more profitable and less risky than reality. How it sneaks in — and how to strip it out. https://therefutation.com/essays/signs-your-trading-strategy-is-overfit/ https://therefutation.com/essays/signs-your-trading-strategy-is-overfit/ Mon, 14 Jul 2026 00:00:00 GMT A smooth equity curve, a Sharpe above 3, a magic parameter value, profit that vanishes without its top trades. Ten concrete tells that a backtested strategy is overfit. https://therefutation.com/essays/out-of-sample-testing-harness/ https://therefutation.com/essays/out-of-sample-testing-harness/ Mon, 14 Jul 2026 00:00:00 GMT Two tiers, next-bar fills, netted fees, and Leave-One-Regime-Out validation. The harness that decides whether an idea gets a dollar or a headstone.