Customer service workers at a Fortune 500 software firm who were given access to generative artificial intelligence tools became 14% more productive on average than those who were not, with the least-skilled workers reaping the most benefit.

That’s according to a new study by researchers at Stanford University and the Massachusetts Institute of Technology who tested the impact of generative AI tools on productivity at the company over the course of a year.

The research marks the first time the impact of generative AI tools on work has been measured outside the lab. Prior studies have benchmarked the capabilities of large language models against tasks in fields like law and medicine — showing that, for example, GPT-4 aces the bar exam in the 90th percentile. Other research has tested the tech’s impact on workers’ performance of isolated writing tasks in small-scale laboratory settings.