Add explainers/precision-recall-curve.md.
Companion to the new ROC Curve and AUC explainer. Explain what a PR curve shows, how average precision differs from AUC, and why PR curves are the more honest picture under heavy class imbalance — exactly the regime most fairness audits live in (rare positives, skewed base rates). Tie the fairness angle to why a high ROC-AUC can look reassuring while precision collapses for a minority subgroup.
Suggested structure (match roc-curve-auc.md / false-positives-vs-false-negatives.md): one-sentence definition → why it matters for fairness → core concept → concrete example tied to a repo audit → runnable detection code → limitations → related concepts/projects/further reading.
Related: roc-curve-auc, false-positives-vs-false-negatives, predictive-parity.
See CONTRIBUTING.md: add explainers/<slug>.md plus a one-line entry in assets/explainers-data.json; the build script generates the page.
Freeze-safe: explainers are fully open for contribution during the paper freeze. If you quote any Fair Code benchmark result, use the frozen numbers in paper/results-frozen/ (never re-run your own) — see CLAUDE.md.
Add
explainers/precision-recall-curve.md.Companion to the new ROC Curve and AUC explainer. Explain what a PR curve shows, how average precision differs from AUC, and why PR curves are the more honest picture under heavy class imbalance — exactly the regime most fairness audits live in (rare positives, skewed base rates). Tie the fairness angle to why a high ROC-AUC can look reassuring while precision collapses for a minority subgroup.
Suggested structure (match roc-curve-auc.md / false-positives-vs-false-negatives.md): one-sentence definition → why it matters for fairness → core concept → concrete example tied to a repo audit → runnable detection code → limitations → related concepts/projects/further reading.
Related: roc-curve-auc, false-positives-vs-false-negatives, predictive-parity.
See CONTRIBUTING.md: add
explainers/<slug>.mdplus a one-line entry inassets/explainers-data.json; the build script generates the page.