Building evaluation automation end-to-end

This is the last lesson of Week 5. The journey through the entire decision loop is now complete: experiments were designed, results were analyzed with statistical rigor, and in L5.5 launch readiness criteria were defined, blocking metrics were checked, and a ship decision memo was written with confidence ranges and segment breakdowns. The ship decision was based on evidence. Real evidence. Not gut feeling. But three weeks later, how can anyone tell that decision was still right? The world does not stop changing when the ship button is pressed. Users change. Data changes. The system itself changes. That is what this lesson is about: continuously validating that the thing shipped with confidence actually works in production. Not a one-time check. An ongoing discipline. This lesson covers how to detect when things drift, what to do about it, and how to build a monitoring plan that catches problems before users do.