The buzz about AI coding tools is unrelenting. To listen to the reports, startups are launching with tiny engineering teams, non-programmers are “vibe-coding” entire apps, and the job market for entry-level programmers is crashing. But according to a METR experiment conducted in the spring of 2025, there’s at least one cohort that AI tools still aren’t serving.METR performed a rigorous study (blog post, full paper) to measure the productivity gain provided by AI tools for experienced developers ...