AI Now Writes Nearly One-Third of New Code on GitHub, Landmark Study Finds

A study published in Science finds that AI now generates nearly 30% of new Python code on GitHub in the United States, up from just 5% in 2022. The gains are real - but they flow almost entirely to experienced developers, not junior ones.

GPT-5.3 Codex vs. Claude Opus 4.6: Two Philosophies, One Problem