Measuring the Impact of Early-2025 AI on Experienced Open-Source Developer Productivity

An important and well-conducted study showing that modern AI-coding tools are detrimental to the developers who:

• are well-experienced;
• work on large code bases;
• know the code base like the back of their hand.

Interestingly, although on average they closed their tasks 19% slower, they still percieved that AI agents provided about 20% speedup!

The authors note that this effect can diminish with new generations of Agents, and, most importantly, there is a wide selection of tasks that already show performance improvement.

So if you’re not deeply familiar with the code base, have limited experience with technologies used, or are developing a greenfield project, an AI agent will likely help.