Your CEO read an article about Copilot saving developers 55% of their time. Now they want to know why your team's velocity hasn't doubled since you deployed it 6 months ago.
The answer: that 55% metric measures something nobody cares about.
The Metrics Trap
GitHub's own study measured how much faster developers completed a simple task (writing an HTTP server) with Copilot vs. without. Developers with Copilot finished 55% faster.
But writing an HTTP server from scratch isn't what your developers do. They modify existing, complex, interconnected systems where the hard part isn't writing code — it's understanding what to write.
What Actually Happens
When teams adopt AI coding tools, the results follow a predictable pattern: