This document summarizes the Plan-Do-Check-Act (PDCA) cycle, also known as the Deming Wheel, which is a systematic process improvement method. It describes the four steps of the cycle as Plan, Do, Check, Act. The Plan step involves planning a change. Do is implementing the change. Check is monitoring and evaluating results. Act is taking action based on lessons learned. Using PDCA facilitates continuous improvement through iterative cycles. It also introduces FOCUS PDCA, which adds five preliminary steps to focus the PDCA process.