- A controlled trial found experienced developers felt 20% faster but were actually 19% slower when using AI tools in familiar codebases.
- AI speeds up typing, which isn't the bottleneck for experts, and adds overhead like prompting, waiting, and reviewing often subtly wrong outputs.
- Team-level data shows increased pull request volume and size but no net delivery gain, with more code churn and less refactoring, indicating verification has become the new bottleneck.
- Tool builders are shifting focus to agent-first IDEs, emphasizing verification over generation, aligning with the identified bottleneck in development workflows.
- The feeling of speed is misleading; successful teams must measure actual production outcomes and restaff review stages, rather than relying on perceived velocity.