Look-Ahead-Bias on wid's bloghttps://wid-blog.github.io/en/tags/look-ahead-bias/Recent content in Look-Ahead-Bias on wid's blogHugoenTue, 12 May 2026 00:00:00 +0000Backtest Pitfalls Case Studyhttps://wid-blog.github.io/en/posts/daily/investment/backtest-pitfalls-case-study/Tue, 12 May 2026 00:00:00 +0000https://wid-blog.github.io/en/posts/daily/investment/backtest-pitfalls-case-study/Concrete cases of look-ahead bias and survivorship bias — full-period momentum normalization, financial disclosure lag, close-on-close fills, S&P 500 reconstitution, the limits of free APIs — followed by an avoidance checklist.