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Bibliographic Details
Main Authors: Becker, Joel, Rush, Nate, Barnes, Elizabeth, Rein, David
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2507.09089
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author Becker, Joel
Rush, Nate
Barnes, Elizabeth
Rein, David
author_facet Becker, Joel
Rush, Nate
Barnes, Elizabeth
Rein, David
contents Despite widespread adoption, the impact of AI tools on software development in the wild remains understudied. We conduct a randomized controlled trial (RCT) to understand how AI tools at the February-June 2025 frontier affect the productivity of experienced open-source developers. 16 developers with moderate AI experience complete 246 tasks in mature projects on which they have an average of 5 years of prior experience. Each task is randomly assigned to allow or disallow usage of early 2025 AI tools. When AI tools are allowed, developers primarily use Cursor Pro, a popular code editor, and Claude 3.5/3.7 Sonnet. Before starting tasks, developers forecast that allowing AI will reduce completion time by 24%. After completing the study, developers estimate that allowing AI reduced completion time by 20%. Surprisingly, we find that allowing AI actually increases completion time by 19%--AI tooling slowed developers down. This slowdown also contradicts predictions from experts in economics (39% shorter) and ML (38% shorter). To understand this result, we collect and evaluate evidence for 20 properties of our setting that a priori could contribute to the observed slowdown effect--for example, the size and quality standards of projects, or prior developer experience with AI tooling. Although the influence of experimental artifacts cannot be entirely ruled out, the robustness of the slowdown effect across our analyses suggests it is unlikely to primarily be a function of our experimental design.
format Preprint
id arxiv_https___arxiv_org_abs_2507_09089
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Measuring the Impact of Early-2025 AI on Experienced Open-Source Developer Productivity
Becker, Joel
Rush, Nate
Barnes, Elizabeth
Rein, David
Artificial Intelligence
Human-Computer Interaction
Software Engineering
I.2
Despite widespread adoption, the impact of AI tools on software development in the wild remains understudied. We conduct a randomized controlled trial (RCT) to understand how AI tools at the February-June 2025 frontier affect the productivity of experienced open-source developers. 16 developers with moderate AI experience complete 246 tasks in mature projects on which they have an average of 5 years of prior experience. Each task is randomly assigned to allow or disallow usage of early 2025 AI tools. When AI tools are allowed, developers primarily use Cursor Pro, a popular code editor, and Claude 3.5/3.7 Sonnet. Before starting tasks, developers forecast that allowing AI will reduce completion time by 24%. After completing the study, developers estimate that allowing AI reduced completion time by 20%. Surprisingly, we find that allowing AI actually increases completion time by 19%--AI tooling slowed developers down. This slowdown also contradicts predictions from experts in economics (39% shorter) and ML (38% shorter). To understand this result, we collect and evaluate evidence for 20 properties of our setting that a priori could contribute to the observed slowdown effect--for example, the size and quality standards of projects, or prior developer experience with AI tooling. Although the influence of experimental artifacts cannot be entirely ruled out, the robustness of the slowdown effect across our analyses suggests it is unlikely to primarily be a function of our experimental design.
title Measuring the Impact of Early-2025 AI on Experienced Open-Source Developer Productivity
topic Artificial Intelligence
Human-Computer Interaction
Software Engineering
I.2
url https://arxiv.org/abs/2507.09089