Study: Coding Agents Added 30% More Code but No More Shipped Work

A Harvard study of 718 firms using Jellyfish data found coding agents raised lines of code by 30%, commits by 20% and PRs by 23%, yet resolved tickets stayed flat. PR review time rose 49%, the changes-requested rate nearly doubled and comments per PR grew 35%.

• Lines of code +30%, commits +20%, PRs +23% after agent adoption
• PR review time rose 49%, changes-requested rate nearly doubled
• Resolved tickets flat; output gain above 12% ruled out
• Headcount showed no decline, with effect near zero