Final answer:
The AAR process is based on four key elements: Observation, Orientation, Decision, Action, providing a structured means to learn and improve from past actions.
Step-by-step explanation:
The four key elements upon which the After Action Review (AAR) process is based are Observation, Orientation, Decision, Action. This approach to post-event analysis involves a structured process for reviewing what happened, understanding why it happened, making decisions on how to improve, and then taking action to implement those improvements. The process is rooted in a cycle of continuous improvement and enables teams and organizations to learn from their experiences.