AI Productivity Paradox Quantified: Developers Report Feeling 24% Faster But Measure 19% Slower — AI PRs Have 32.7% Acceptance Rate vs 84.4% for Human Code

Faros AI·medium signal

Multiple 2026 studies converge on a 43-percentage-point gap between perceived and measured AI coding productivity. Key metrics: AI-generated PRs have a 32.7% acceptance rate vs 84.4% human, AI code has 1.7x more bugs and 15-18% more security vulnerabilities, review times increase 91% at team level, and developers spend 45% of their time debugging AI output. The sweet spot appears to be 25-40% AI-generated code, where teams see 10-15% real productivity gains while review overhead stays manageable. 41% of all code is now AI-generated, but 21% of AI licenses remain underutilized.