How to Spot Lookahead Bias and Curve-Fitting in Quantitative Backtests [2026]
Date Published
1. The Anatomy of Lookahead Leaks
Why Novice Quants Build Fake Million-Dollar Backtests
In Python, calling `.shift(-1)` or using functions that peek ahead into the dataframe creates instant 5.0+ Sharpe ratios that fail instantly when hooked up to a live broker API. Systematic engines must enforce causal, forward-only data pipelines.
Was this article helpful?
Your feedback directly guides the research and strategies we publish next.
Click stars to vote