This case study will teach attendees to apply lessons learned from previous projects to their current process improvement efforts. After action reviews (AARs) are a rigorous method to capture lessons learned during a project. The key to AARs are the following questions: What was supposed to happen? What actually happened? Why were there differences? The presenter will explain how he used AARs to gather lessons learned from each phase of a major process improvement project and how he and his team assured the lessons gathered were applied to improve results in later phases of the project.