In DMAIC, which phase monitors the system after changes to ensure gains are sustained?

• A. Control
• B. Analyze
• C. Measure
• D. Define

Answer: (A)

Sustaining gains through ongoing monitoring is the purpose of the Control phase. In this phase you lock in improvements with a formal control plan that specifies what to monitor, acceptable variation, who is responsible, and how to respond if performance drifts. Tools like control charts, standardized work, and dashboards are used to detect deviations quickly and keep the process at its new, improved level. Training and documentation are updated so operations can maintain the change over time. The earlier stages—Define, Measure, Analyze, and Improve—focus on identifying the problem, understanding current performance, root causes, and implementing solutions, not on sustaining the gains after changes.