← March 30, 2026 briefingTech
AI tools make developers 19% slower, study finds
A rigorous study — the METR study — measured experienced open-source developers working on their own codebases and found AI coding tools made them 19% slower, even as the same developers believed they were 24% faster. The 43-point gap between perception and reality helps explain why AI tool adoption keeps climbing even as trust erodes. It is the most concrete evidence yet that AI-assisted coding confidence is systematically miscalibrated.
