Tracking KPIs is not enough to ensure the success of your Lean Six Sigma projects. To drive continuous improvement and sustain the results, you should use the Plan-Do-Check-Act (PDCA) cycle to apply the KPIs in each phase of your project. During the Plan phase, you should define your project goals, scope, and KPIs. Conduct a gap analysis between the baseline and the target, identify and prioritize root causes of the problem, and develop and test possible solutions. The Do phase involves implementing the selected solutions, collecting and recording data for your KPIs, observing and documenting effects of changes. The Check phase requires analyzing data and comparing performance before and after changes, evaluating impact of solutions on KPIs, verifying if target is met or exceeded, and identifying any issues or risks. Finally, during the Act phase you should standardize successful solutions, document and communicate results and best practices, recognize and reward team members, and identify new opportunities for improvement.