AI coding agents write 30% more code at firms, but software output stays flat as code review slows
- Adopting AI coding agents raised total lines of code by 30 percent, commits by 20 percent, and pull requests by 23 percent at the firms in a Harvard study covering over 700 software companies.
- Resolution rates for Jira Issues and Epics did not change in a statistically significant way after AI tools arrived, so the extra code did not become more finished software.
- Average review time from pull request submission to merge rose 49 percent, and the share of pull requests needing changes nearly doubled.
- Comments per pull request rose 35 percent, and the share of workers doing code reviews grew 14 percent, while researchers could not attribute significant employment changes to AI.
- By March 2026, 80 percent of firms used some AI code review, but AI agents accounted for only 10.8 percent of pull requests and 23.3 percent of review comments.
Hacker News 의견들
Still, AI keeps catching bugs I'd have missed. Most of the 12 items on the list would never fire in practice, but you still have to figure out each one: fix, document, file, or ignore.
Some orgs skip human review entirely and lean on QA and unit tests. My old place dropped end-to-end QA after the head of engineering decided to shift left on automation.
My guess is the big change in review culture will come from startups that start with a no-human-review policy and keep it as they grow. Established teams won't get there first. If those startups ship much faster, everyone else will copy them.
I'm pretty senior and I hate code review. It's the most tedious part of my job. I don't get why people cling to line-by-line review.
I think non-senior engineers don't see how much of a mess barely reviewed AI code makes. I've seen projects where the code itself was fine, but the product was a disaster because AI did the reviews and bad decisions went straight to prod.
We shouldn't give up line-by-line review for serious apps. My company says developer velocity will double in 2-3 years, but our team spends about 10% of its time writing code and 90% on design and analysis. Doubling coding speed only makes us about 5% faster overall.
I actually dislike traditional code review too, mostly because GitHub and GitLab review UIs are clumsy and humans miss correctness and security problems. My best results have come from agent-assisted review inside a real IDE, with agents doing a first pass for correctness.