A controlled trial found that experienced developers felt about 20% faster while actually working 19% slower when using AI tools. AI increases typing speed but introduces overhead, prompting, waiting, and reviewing output, which can hinder productivity for experts in familiar codebases.

Preliminary data from a longitudinal AI impact study indicates that AI productivity gains are approximately 10%, rather than the previously suggested 10x. High expectations for AI productivity, influenced by social media and vendor marketing, may not align with these findings.