backtesting
Paper Trading vs Backtesting: What Each One Can and Cannot Prove
Both look like validation. Neither is sufficient alone. Here's exactly what each test can and cannot prove — and why confusing them costs traders real money.
quant trading
Walk-Forward Analysis
Walk-Forward Analysis: The Right Way to Validate a Trading Strategy
A single in-sample/out-of-sample split feels rigorous — it isn't. Walk-forward analysis is the only test that mimics how a strategy actually ages in the market.
survivorship bias
Your Backtest Only Sees the Survivors
Test a strategy on today's top coins or stocks and you've already rigged the result. Survivorship bias quietly inflates every backtest that ignores the assets that died.
Win Rate
A 90% Win Rate That Loses Money: The Win-Rate Trap
Win rate is the most cited and most misleading number in trading. Here's how a strategy that wins 90% of the time can still bleed you dry — and what to track instead.
Lookahead Bias
Your Backtest Peeked at the Future. That's Why It Looks Perfect.
Lookahead bias is the quietest backtest killer: a single accidental glance at future data turns random noise into a flawless equity curve. Here's how it sneaks in — and how to catch it.
backtesting
I Generated 1,500 Trading Strategies. 114 "Passed" on Bitcoin. None Were Real.
A hands-on demonstration of why in-sample / out-of-sample / holdout testing isn't enough to catch overfitting — and the statistics that actually are.