Research
Measured, verifiable writing on point-in-time data and backtest honesty. Every number traces to the dataset or a public filing.
2026-07-05 · 9 min read
Your Backtest Saw the Future: Lookahead Bias in Fundamental Data
Fundamentals go public ~43 days after period end (measured: 313,562 EDGAR rows). How lookahead bias inflates backtests, and how to detect and fix it.
2026-07-05 · 7 min read
Point-in-Time Fundamentals Data: What It Is, Why It Matters, and How to Choose
What point-in-time fundamentals data is, why it kills lookahead bias in backtests, what to look for in a dataset, and an honest survey of your options.
2026-07-05 · 7 min read
How to Build a Point-in-Time Fundamentals Database from SEC EDGAR (and When Not To)
A build-vs-buy guide to point-in-time fundamentals from SEC EDGAR companyfacts: the real steps, where DIY breaks, and when a $49/mo API is the shortcut.
2026-07-06 · 7 min read
Survivorship Bias vs Lookahead Bias: The Two Silent Backtest Killers
Two backtest killers, compared: what each is, why lookahead hides in a merge, how fundamentals data causes both, and how PIT data + a stable universe fix them.