Backtesting blog
Practical, no-hype guides to testing trading strategies honestly. Every post links to the check in the lab that puts the idea into practice.
How to read a backtest report without fooling yourself
Net return, drawdown, trade count, buy and hold, and robustness checks: what each number in a backtest report tells you, and what it can’t.
Read the guide · 6 min readOverfitting in backtesting: why great results often fail live
How testing many variations makes noise look like an edge, the warning signs in a report, and simple habits that reduce overfitting.
Read the guide · 6 min readOut-of-sample testing: how to use a holdout period honestly
Why scoring the last part of your history on its own catches overfitting, how Backte.st’s unseen-period check works, and how to avoid using it up.
Read the guide · 5 min readTransaction costs in backtests: commission, slippage and spread
Why small per-trade costs decide whether short-term strategies survive, how to estimate them in basis points, and what the doubled-costs check shows.
Read the guide · 5 min readParameter robustness: does your strategy survive nearby settings?
Why a strategy that only works at one exact setting is suspicious, how to test nearby parameters, and how to read a sensitivity result.
Read the guide · 5 min readLook-ahead bias and execution timing in backtests
How using information you wouldn’t have had inflates backtests, why fills at the next open matter, and what the delayed-entry check reveals.
Read the guide · 5 min readMonte Carlo trade shuffling: how bad could the drawdown get?
Why the drawdown in a single backtest understates risk, how reshuffling trade order estimates a worse but plausible case, and its limits.
Read the guide · 5 min readSurvivorship bias: why the markets you choose matter
How testing on today’s winners inflates backtests, why delisted assets disappear from data, and practical ways to choose markets more fairly.
Read the guide · 5 min read